US20070020868A1 - Semiconductor processing method and field effect transistor - Google Patents
Semiconductor processing method and field effect transistor Download PDFInfo
- Publication number
- US20070020868A1 US20070020868A1 US11/519,243 US51924306A US2007020868A1 US 20070020868 A1 US20070020868 A1 US 20070020868A1 US 51924306 A US51924306 A US 51924306A US 2007020868 A1 US2007020868 A1 US 2007020868A1
- Authority
- US
- United States
- Prior art keywords
- gate
- oxide layer
- edges
- chlorine
- gate oxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000004065 semiconductor Substances 0.000 title description 6
- 230000005669 field effect Effects 0.000 title 1
- 238000003672 processing method Methods 0.000 title 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 70
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 70
- 239000000460 chlorine Substances 0.000 claims abstract description 70
- 229910052731 fluorine Inorganic materials 0.000 claims abstract description 55
- 239000011737 fluorine Substances 0.000 claims abstract description 55
- 125000006850 spacer group Chemical group 0.000 claims abstract description 52
- 238000000034 method Methods 0.000 claims abstract description 44
- 239000000463 material Substances 0.000 claims abstract description 19
- 239000000758 substrate Substances 0.000 claims abstract description 12
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 49
- 239000002019 doping agent Substances 0.000 claims description 11
- 238000000137 annealing Methods 0.000 claims description 10
- 238000009792 diffusion process Methods 0.000 claims description 10
- 239000011800 void material Substances 0.000 claims description 7
- 239000011810 insulating material Substances 0.000 claims description 3
- 238000000151 deposition Methods 0.000 claims 3
- 238000005530 etching Methods 0.000 claims 2
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 abstract 6
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 18
- 239000012634 fragment Substances 0.000 description 12
- 238000010276 construction Methods 0.000 description 11
- 230000000694 effects Effects 0.000 description 9
- 239000000377 silicon dioxide Substances 0.000 description 9
- 230000015572 biosynthetic process Effects 0.000 description 8
- 229910052681 coesite Inorganic materials 0.000 description 7
- 229910052906 cristobalite Inorganic materials 0.000 description 7
- 229910052682 stishovite Inorganic materials 0.000 description 7
- 229910052905 tridymite Inorganic materials 0.000 description 7
- 230000005684 electric field Effects 0.000 description 5
- 239000002784 hot electron Substances 0.000 description 4
- 239000007943 implant Substances 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 230000002411 adverse Effects 0.000 description 3
- 238000005468 ion implantation Methods 0.000 description 3
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- 230000000712 assembly Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000036039 immunity Effects 0.000 description 2
- 238000011065 in-situ storage Methods 0.000 description 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 2
- 229920005591 polysilicon Polymers 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000008439 repair process Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 108091006149 Electron carriers Proteins 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000010893 electron trap Methods 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 230000005527 interface trap Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005381 potential energy Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910021332 silicide Inorganic materials 0.000 description 1
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- ATVLVRVBCRICNU-UHFFFAOYSA-N trifluorosilicon Chemical compound F[Si](F)F ATVLVRVBCRICNU-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/26—Bombardment with radiation
- H01L21/263—Bombardment with radiation with high-energy radiation
- H01L21/265—Bombardment with radiation with high-energy radiation producing ion implantation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
- H01L21/28008—Making conductor-insulator-semiconductor electrodes
- H01L21/28017—Making conductor-insulator-semiconductor electrodes the insulator being formed after the semiconductor body, the semiconductor being silicon
- H01L21/28158—Making the insulator
- H01L21/28167—Making the insulator on single crystalline silicon, e.g. using a liquid, i.e. chemical oxidation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/40—Electrodes ; Multistep manufacturing processes therefor
- H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/49—Metal-insulator-semiconductor electrodes, e.g. gates of MOSFET
- H01L29/51—Insulating materials associated therewith
- H01L29/511—Insulating materials associated therewith with a compositional variation, e.g. multilayer structures
- H01L29/512—Insulating materials associated therewith with a compositional variation, e.g. multilayer structures the variation being parallel to the channel plane
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/6656—Unipolar field-effect transistors with an insulated gate, i.e. MISFET using multiple spacer layers, e.g. multiple sidewall spacers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
- H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
- H01L29/66409—Unipolar field-effect transistors
- H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
- H01L29/66568—Lateral single gate silicon transistors
- H01L29/66575—Lateral single gate silicon transistors where the source and drain or source and drain extensions are self-aligned to the sides of the gate
- H01L29/6659—Lateral single gate silicon transistors where the source and drain or source and drain extensions are self-aligned to the sides of the gate with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/76—Unipolar devices, e.g. field effect transistors
- H01L29/772—Field effect transistors
- H01L29/78—Field effect transistors with field effect produced by an insulated gate
- H01L29/7833—Field effect transistors with field effect produced by an insulated gate with lightly doped drain or source extension, e.g. LDD MOSFET's; DDD MOSFET's
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
- H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
- H01L21/3105—After-treatment
- H01L21/3115—Doping the insulating layers
Definitions
- This invention relates to methods of forming transistor gates and to transistor constructions.
- MOS devices As transistor gate dimensions are reduced and the supply voltage remains constant, the lateral field generated in MOS devices increases. As the electric field becomes strong enough, it gives rise to so-called “hot-carrier” effects in MOS devices. This has become a significant problem in NMOS devices with channel lengths smaller than 1.5 micron, and in PMOS devices with sub-micron channel lengths.
- High electric fields cause the electrons in the channel to gain kinetic energy, with their energy distribution being shifted to a much higher value than that of electrons which are in thermal equilibrium within the lattice.
- the maximum electric field in a MOSFET device occurs near the drain during saturated operation, with the hot electrons thereby becoming hot near the drain edge of the channel. Such hot electrons can cause adverse effects in the device.
- Device performance degradation from hot electron effects have been in the past reduced by a number of techniques.
- One technique is to reduce the voltage applied to the device, and thus decrease in the electric field. Further, the time the device is under the voltage stress can be shortened, for example, by using a lower duty cycle and clocked logic. Further, the density of trapping sites in the gate oxide can be reduced through the use of special processing techniques. Also, the use of lightly doped drains and other drain engineering design techniques can be utilized.
- fluorine-based oxides can improve hot-carrier immunity by lifetime orders of magnitude. This improvement is understood to mainly be due to the presence of fluorine at the Si/SiO 2 interface reducing the number of strained Si/O bonds, as fewer sites are available for defect formation. Improvements at the Si/SiO 2 interface reduces junction leakage, charge trapping and interface trap generation. However, optimizing the process can be complicated. In addition, electron-trapping and poor leakage characteristics can make such fluorine-doped oxides undesirable and provide a degree of unpredictability in device operation. Use of fluorine across the entire channel length has been reported in, a) K. Ohyu et al., “Improvement of SiO 2 /Si Interface Properties by Fluorine Implantation”; and b) P. J. Wright, et al., “The Effect of Fluorine On Gate Dielectric Properties”.
- a method of forming a transistor includes forming a gate oxide layer over a semiconductive substrate. Chlorine is provided within the gate oxide layer. A gate is formed proximate the gate oxide layer. In another aspect, a gate and a gate oxide layer are formed in overlapping relation, with the gate having opposing edges and a center therebetween. At least one of chlorine or fluorine is concentrated in the gate oxide layer within the overlap more proximate at least one of the gate edges than the center. The center is preferably substantially void of either fluorine of chlorine. In one implementation, at least one of chlorine or flouring is angle ion implanted to beneath the edges of the gate.
- sidewall spacers are formed proximate the opposing lateral edges, with the sidewall spacers comprising at least one of chlorine or fluorine.
- the spacers are annealed at a temperature and for a time period effective to diffuse the fluorine or chlorine from the spacers into the gate oxide layer to beneath the gate.
- Transistors fabricated by such methods, and other methods, are also contemplated.
- FIG. 1 is a sectional view of a semiconductor wafer fragment in accordance with the invention.
- FIG. 2 is a sectional view of an alternate semiconductor wafer fragment at one step of a method in accordance with the invention.
- FIG. 3 is a view of the FIG. 2 wafer at a processing step subsequent to that shown by FIG. 2 .
- FIG. 4 is a sectional view of another semiconductor wafer fragment at an alternate processing step in accordance with the invention.
- FIG. 5 is a view of the FIG. 4 wafer fragment at a processing step subsequent to that depicted by FIG. 4 .
- FIG. 6 is a view of the FIG. 4 wafer fragment at a processing step subsequent to that depicted by FIG. 5 .
- FIG. 7 is a view of the FIG. 4 wafer at an alternate processing step to that depicted by FIG. 6 .
- FIG. 8 is a sectional view of another semiconductor wafer fragment at another processing step in accordance with the invention.
- FIG. 9 is a view of the FIG. 8 wafer at a processing step subsequent to that depicted by FIG. 8 .
- FIG. 10 is a sectional view of still another embodiment wafer fragment at a processing step in accordance with another aspect of the invention.
- a semiconductor wafer fragment in process is indicated in FIG. 1 with reference numeral 10 .
- Such comprises a bulk semiconductive substrate 12 which supports field oxide regions 14 and a gate oxide layer 16 .
- the term “semiconductive substrate” is defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials).
- substrate refers to any supporting structure, including, but not limited to, the semiconductive substrates described above.
- a gate structure 18 is formed proximate gate oxide 16 , such as in an overlapping relationship.
- a top gated construction is shown, although bottom gated constructions could also be utilized.
- Gate construction 18 is comprised of a first conductive material portion 20 (i.e., conductively doped polysilicon), and a higher conductive layer 22 (i.e., a silicide such as WSi x ).
- An insulating cap 24 is provided over layer 22 , with SiO 2 and Si 3 N 4 being example materials.
- gate construction 18 defines opposing gate edges 26 and 28 , and a center 30 therebetween. The invention is believed to have its greatest impact where the gate width between edges 26 and 28 (i.e., the channel length) is 0.25 micron or less.
- Chlorine is provided within gate oxide layer 16 as indicated in the figure by the hash marks, and thus between semiconductive material of substrate 12 and transistor gate 18 . Chlorine can be provided before or after formation of gate construction 18 .
- the chlorine in layer 16 can be provided by gas diffusion, ion implantation or in situ as initially deposited or formed. Preferred dopant concentration of the chlorine within oxide layer 16 is from about 1 ⁇ 10 19 atoms/cm 3 to about 1 ⁇ 10 21 atoms/cm 3 .
- a source, a drain, and insulating sidewall spacers over gate construction 18 can be provided. Chlorine based gate oxides can improve hot-carrier immunity.
- the chlorine present at the Si/SiO 2 interface reduces the number of strained Si/O bonds, as fewer sites are available for defect formation. Improvements at the Si/SiO 2 interface will reduce junction leakage, the probability of charge trapping and interface state generation, thus improving device characteristics.
- Wafer fragment 10 b ideally comprises a gate oxide layer 16 b which is initially provided to be essentially undoped with chlorine.
- the FIG. 2 construction is subjected to angle ion implanting (depicted with arrows 32 ) to implant at least one of chlorine or fluorine into gate oxide layer 16 b beneath edges 26 and 28 of gate 18 .
- a preferred angle for the implant is between from about 0.5° to about 10° from perpendicular to gate oxide layer 16 b.
- An example energy range is from 20 to 50 keV, with 50 keV being a preferred example.
- An example implant species is SiF 3 , to provide a fluorine dose of from about 1 ⁇ 10 15 atoms/cm 2 to about 3 ⁇ 1 15 atoms/cm 2 , with 2 ⁇ 10 15 atoms/cm 2 being a specific example.
- the resultant preferred implanted dopant concentration within layer 16 b is from about 1 ⁇ 10 19 atom/cm 3 to about 1 ⁇ 10 21 atoms/cm 3 .
- the concentrated regions from such preferred processing will extend inwardly within gate oxide layer 16 b relative to gate edges 26 and 28 a preferred distance of from about 50 Angstroms to about 500 Angstroms. Such is exemplified in the Figures by boundaries 34 . In the physical product, such boundaries would not physically exist, but rather the implant concentration would preferably appreciably drop off over a very short distance of the channel length.
- Annealing is preferably subsequently conducted to repair damage to the gate oxide layer caused by the ion implantation.
- Example conditions include exposure of the substrate to a temperature of from 700° C. to 1000° C. in an inert atmosphere such as N 2 at a pressure from 100 mTorr-760 Torr for from about 20 minutes to 1 hour. Such can be conducted as a dedicated anneal, or in conjunction with other wafer processing whereby such conditions are provided. Such will also have the effect of causing encroachment or diffusion of the implanted atoms to provide barriers 34 to extend inwardly from edges 26 and 28 approximately from about 50 Angstroms to about 500 Angstroms.
- Such provides but one example of doping and concentrating at least one of chlorine or fluorine in the gate oxide layer within the overlap region between the semiconductive material and the gate more proximate the gate edges 26 and 28 than gate center 30 .
- Such preferably provides a pair of spaced and opposed concentration regions in the gate oxide layer, with the area between the concentration regions being substantially undoped with chlorine and fluorine.
- substantially undoped and substantially void means having a concentration range of less than or equal to about 1 ⁇ 10 16 atoms/cm 3 .
- insulative sidewall spacers 36 are formed over the gate edges.
- FIGS. 2-3 embodiment illustrated exemplary provision of concentrated regions more proximate the gate edges by angle ion implanting and subsequent anneal. Alternate processing is described with other embodiments with reference to FIGS. 4-10 .
- a first alternate embodiment is shown in FIGS. 4-6 , with like numerals from the first described embodiment being utilized where appropriate, with differences being indicated with the suffix “c” or with different numerals.
- Wafer fragment 10 c is shown at a processing step subsequent to that depicted by FIG. 1 (however preferably with no chlorine provided in the gate oxide layer).
- the gate oxide material of layer 16 c is etched substantially selective relative to silicon to remove oxide thereover, as shown.
- a layer of oxide to be used for spacer formation is thereafter deposited over substrate 12 and gate construction 18 c. Such is anisotropically etched to form insulative sidewall spacers 44 proximate opposing lateral edges 26 and 28 of gate 18 .
- spacers are formed to cover less than all of the conductive material of lateral edges 26 and 28 of gate 18 . Further in this depicted embodiment, such spacers 44 do not overlie any gate oxide material over substrate 12 , as such has been completed etched away.
- Spacers 44 are provided to be doped with at least one of chlorine or fluorine, with an example dopant concentration being 1 ⁇ 10 21 atoms/cm 3 .
- Such doping could be provided in any of a number of ways.
- the deposited insulating layer from which spacers 44 are formed for example SiO 2 , could be in situ doped during its formation to provide the desired fluorine and/or chlorine concentration.
- such could be gas diffusion doped after formation of such layer, either before or after the anisotropic etch to form the spacers.
- ion implanting could be conducted to provide a desired dopant concentration within spacers 44 .
- spacers 44 are annealed at a temperature and for a time period effective to diffuse the dopant fluorine or chlorine from such spacers into gate oxide layer 16 c beneath gate 18 .
- Sample annealing conditions are as described above with respect to repair of ion implantation damage. Such can be conducted as a dedicated anneal, or as a byproduct of subsequent wafer processing wherein such conditions are inherently provided.
- Such provides the illustrated concentration regions 46 proximate lateral edges 26 and 28 with gate oxide material therebetween preferably being substantially undoped with either chlorine or fluorine.
- another layer of insulating material i.e., silicon nitride or silicon dioxide
- Such is anisotropically etched to form spacers 48 about spacers 44 and gate construction 18 .
- spacer 48 formation occurs after annealing to cause effective diffusion doping from spacers 44 into gate oxide layer 16 c.
- FIG. 7 Alternate processing with respect to FIG. 5 is shown in FIG. 7 . Like numerals from the first described embodiment are utilized where appropriate with differences being indicated with the suffix “d”.
- doped spacers 44 have been stripped from the substrate prior to provision of spacers 48 . Accordingly, diffusion doping of chlorine or fluorine from spacers 44 would be conducted prior to such stripping in this embodiment.
- the FIG. 7 processing is believed to be preferred to that of FIG. 6 , such that the chlorine or fluorine dopant atoms won't have any adverse effect on later or other processing steps in ultimate device operation or fabrication. For example, chlorine and fluorine may not be desired in the preferred polysilicon material of the gate.
- FIG. 8 illustrates a wafer fragment 10 e which is similar to that depicted by FIG. 4 with the exception that gate oxide layer 16 e has not been stripped or etched laterally outward of gate edges 26 and 28 prior to spacer 44 e formation. Accordingly in such embodiment, spacers 44 e are formed to overlie gate oxide layer 16 e.
- such spacers are subjected to appropriate annealing conditions as described above to cause diffusion doping of the chlorine or fluorine into the gate oxide layer 16 e and beneath gate 18 from laterally outward of gate edges 26 and 28 .
- This embodiment is not believed to be as preferred as those depicted by FIGS. 4-7 , in that the dopant must diffuse both initially downwardly into gate oxide layer 16 and then laterally to beneath gate edges 26 and 28 .
- FIG. 10 is similar to the FIGS. 8-9 embodiment. However, gate oxide layer 16 f is etched only partially into laterally outward of gate edges 26 and 28 , thus reducing its thickness. Chlorine and/or fluorine doped spacers 44 f are subsequently formed as described above. A diffusion annealing is then conducted. In comparison to the FIG. 8 embodiment, the FIG. 10 embodiment provides a portion of gate oxide layer 16 f to be laterally outwardly exposed, such that dopant diffusion to beneath gate edges 26 and 28 is facilitated.
- the above-described embodiments preferably place doped chlorine or fluorine proximate both gate edges 26 and 28 within the respective gate oxide layers. Alternately, such greater concentration could be provided proximate only one of the gate edges, such as the drain edge where the hot carrier effects are most problematic.
Abstract
A method of forming a transistor gate includes forming a gate oxide layer over a semiconductive substrate. Chlorine is provided within the gate oxide layer. A gate is formed proximate the gate oxide layer. In another method, a gate and a gate oxide layer are formed in overlapping relation, with the gate having opposing edges and a center therebetween. At least one of chlorine or fluorine is concentrated in the gate oxide layer within the overlap more proximate at least one of the gate edges than the center. Preferably, the central region is substantially undoped with fluorine and chlorine. The chlorine and/or fluorine can be provided by forming sidewall spacers proximate the opposing lateral edges of the gate, with the sidewall spacers comprising at least one of chlorine or fluorine. The spacers are annealed at a temperature and for a time effective to diffuse the fluorine or chlorine into the gate oxide layer to beneath the gate. Transistors and transistor gates fabricated according to the above and other methods are disclosed. Further, a transistor includes a semiconductive material and a transistor gate having gate oxide positioned therebetween. A source is formed laterally proximate one of the gate edges and a drain is formed laterally proximate the other of the gate edges. First insulative spacers are formed proximate the gate edges, with the first insulative spacers being doped with at least one of chlorine or fluorine. Second insulative spacers formed over the first insulative spacers.
Description
- This invention relates to methods of forming transistor gates and to transistor constructions.
- As transistor gate dimensions are reduced and the supply voltage remains constant, the lateral field generated in MOS devices increases. As the electric field becomes strong enough, it gives rise to so-called “hot-carrier” effects in MOS devices. This has become a significant problem in NMOS devices with channel lengths smaller than 1.5 micron, and in PMOS devices with sub-micron channel lengths.
- High electric fields cause the electrons in the channel to gain kinetic energy, with their energy distribution being shifted to a much higher value than that of electrons which are in thermal equilibrium within the lattice. The maximum electric field in a MOSFET device occurs near the drain during saturated operation, with the hot electrons thereby becoming hot near the drain edge of the channel. Such hot electrons can cause adverse effects in the device.
- First, those electrons that acquire greater than or equal to 1.5 eV of energy can lose it via impact ionization, which generates electron-hole pairs. The total number of electron-hole pairs generated by impact ionization is exponentially dependent on the reciprocal of the electric field. In the extreme, this electron-hole pair generation can lead to a form of avalanche breakdown. Second, the hot holes and electrons can overcome the potential energy barrier between the silicon and the silicon dioxide, thereby causing hot carriers to become injected into the gate oxide. Each of these events brings about its own set of repercussions.
- Device performance degradation from hot electron effects have been in the past reduced by a number of techniques. One technique is to reduce the voltage applied to the device, and thus decrease in the electric field. Further, the time the device is under the voltage stress can be shortened, for example, by using a lower duty cycle and clocked logic. Further, the density of trapping sites in the gate oxide can be reduced through the use of special processing techniques. Also, the use of lightly doped drains and other drain engineering design techniques can be utilized.
- Further, it has been recognized that fluorine-based oxides can improve hot-carrier immunity by lifetime orders of magnitude. This improvement is understood to mainly be due to the presence of fluorine at the Si/SiO2 interface reducing the number of strained Si/O bonds, as fewer sites are available for defect formation. Improvements at the Si/SiO2 interface reduces junction leakage, charge trapping and interface trap generation. However, optimizing the process can be complicated. In addition, electron-trapping and poor leakage characteristics can make such fluorine-doped oxides undesirable and provide a degree of unpredictability in device operation. Use of fluorine across the entire channel length has been reported in, a) K. Ohyu et al., “Improvement of SiO2/Si Interface Properties by Fluorine Implantation”; and b) P. J. Wright, et al., “The Effect of Fluorine On Gate Dielectric Properties”.
- In one implementation, a method of forming a transistor includes forming a gate oxide layer over a semiconductive substrate. Chlorine is provided within the gate oxide layer. A gate is formed proximate the gate oxide layer. In another aspect, a gate and a gate oxide layer are formed in overlapping relation, with the gate having opposing edges and a center therebetween. At least one of chlorine or fluorine is concentrated in the gate oxide layer within the overlap more proximate at least one of the gate edges than the center. The center is preferably substantially void of either fluorine of chlorine. In one implementation, at least one of chlorine or flouring is angle ion implanted to beneath the edges of the gate. In another, sidewall spacers are formed proximate the opposing lateral edges, with the sidewall spacers comprising at least one of chlorine or fluorine. The spacers are annealed at a temperature and for a time period effective to diffuse the fluorine or chlorine from the spacers into the gate oxide layer to beneath the gate. Transistors fabricated by such methods, and other methods, are also contemplated.
- Preferred embodiments of the invention are described below with reference to the following accompanying drawings.
-
FIG. 1 is a sectional view of a semiconductor wafer fragment in accordance with the invention. -
FIG. 2 is a sectional view of an alternate semiconductor wafer fragment at one step of a method in accordance with the invention. -
FIG. 3 is a view of theFIG. 2 wafer at a processing step subsequent to that shown byFIG. 2 . -
FIG. 4 is a sectional view of another semiconductor wafer fragment at an alternate processing step in accordance with the invention. -
FIG. 5 is a view of theFIG. 4 wafer fragment at a processing step subsequent to that depicted byFIG. 4 . -
FIG. 6 is a view of theFIG. 4 wafer fragment at a processing step subsequent to that depicted byFIG. 5 . -
FIG. 7 is a view of theFIG. 4 wafer at an alternate processing step to that depicted byFIG. 6 . -
FIG. 8 is a sectional view of another semiconductor wafer fragment at another processing step in accordance with the invention. -
FIG. 9 is a view of theFIG. 8 wafer at a processing step subsequent to that depicted byFIG. 8 . -
FIG. 10 is a sectional view of still another embodiment wafer fragment at a processing step in accordance with another aspect of the invention. - This disclosure of the invention is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).
- A semiconductor wafer fragment in process is indicated in
FIG. 1 withreference numeral 10. Such comprises a bulksemiconductive substrate 12 which supportsfield oxide regions 14 and agate oxide layer 16. In the context of this document, the term “semiconductive substrate” is defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure, including, but not limited to, the semiconductive substrates described above. - A
gate structure 18 is formedproximate gate oxide 16, such as in an overlapping relationship. A top gated construction is shown, although bottom gated constructions could also be utilized.Gate construction 18 is comprised of a first conductive material portion 20 (i.e., conductively doped polysilicon), and a higher conductive layer 22 (i.e., a silicide such as WSix). Aninsulating cap 24 is provided overlayer 22, with SiO2 and Si3N4 being example materials. For purposes of the continuing discussion,gate construction 18 definesopposing gate edges center 30 therebetween. The invention is believed to have its greatest impact where the gate width betweenedges 26 and 28 (i.e., the channel length) is 0.25 micron or less. - Chlorine is provided within
gate oxide layer 16 as indicated in the figure by the hash marks, and thus between semiconductive material ofsubstrate 12 andtransistor gate 18. Chlorine can be provided before or after formation ofgate construction 18. For example, the chlorine inlayer 16 can be provided by gas diffusion, ion implantation or in situ as initially deposited or formed. Preferred dopant concentration of the chlorine withinoxide layer 16 is from about 1×1019 atoms/cm3 to about 1×1021 atoms/cm3. A source, a drain, and insulating sidewall spacers overgate construction 18 can be provided. Chlorine based gate oxides can improve hot-carrier immunity. The chlorine present at the Si/SiO2 interface reduces the number of strained Si/O bonds, as fewer sites are available for defect formation. Improvements at the Si/SiO2 interface will reduce junction leakage, the probability of charge trapping and interface state generation, thus improving device characteristics. - A second embodiment is described with reference to
FIGS. 2 and 3 . Like numerals from the first described embodiment are utilized when appropriate, with differences being indicated by the suffix “b” or with different numerals.Wafer fragment 10 b ideally comprises agate oxide layer 16 b which is initially provided to be essentially undoped with chlorine. TheFIG. 2 construction is subjected to angle ion implanting (depicted with arrows 32) to implant at least one of chlorine or fluorine intogate oxide layer 16 b beneathedges gate 18. A preferred angle for the implant is between from about 0.5° to about 10° from perpendicular togate oxide layer 16 b. An example energy range is from 20 to 50 keV, with 50 keV being a preferred example. An example implant species is SiF3, to provide a fluorine dose of from about 1×1015 atoms/cm2 to about 3×115 atoms/cm2, with 2×1015 atoms/cm2 being a specific example. The resultant preferred implanted dopant concentration withinlayer 16 b is from about 1×1019 atom/cm3 to about 1×1021 atoms/cm3. - The concentrated regions from such preferred processing will extend inwardly within
gate oxide layer 16 b relative to gate edges 26 and 28 a preferred distance of from about 50 Angstroms to about 500 Angstroms. Such is exemplified in the Figures byboundaries 34. In the physical product, such boundaries would not physically exist, but rather the implant concentration would preferably appreciably drop off over a very short distance of the channel length. - Annealing is preferably subsequently conducted to repair damage to the gate oxide layer caused by the ion implantation. Example conditions include exposure of the substrate to a temperature of from 700° C. to 1000° C. in an inert atmosphere such as N2 at a pressure from 100 mTorr-760 Torr for from about 20 minutes to 1 hour. Such can be conducted as a dedicated anneal, or in conjunction with other wafer processing whereby such conditions are provided. Such will also have the effect of causing encroachment or diffusion of the implanted atoms to provide
barriers 34 to extend inwardly fromedges - Such provides but one example of doping and concentrating at least one of chlorine or fluorine in the gate oxide layer within the overlap region between the semiconductive material and the gate more proximate the gate edges 26 and 28 than
gate center 30. Such preferably provides a pair of spaced and opposed concentration regions in the gate oxide layer, with the area between the concentration regions being substantially undoped with chlorine and fluorine. In the context of this document, “substantially undoped” and “substantially void” means having a concentration range of less than or equal to about 1×1016 atoms/cm3. - Referring to
FIG. 3 , subsequent processing is illustrated wherebyinsulative sidewall spacers 36 are formed over the gate edges. Asource region 38 and adrain region 40, as well asLDD regions 42, are provided. - The
FIGS. 2-3 embodiment illustrated exemplary provision of concentrated regions more proximate the gate edges by angle ion implanting and subsequent anneal. Alternate processing is described with other embodiments with reference toFIGS. 4-10 . A first alternate embodiment is shown inFIGS. 4-6 , with like numerals from the first described embodiment being utilized where appropriate, with differences being indicated with the suffix “c” or with different numerals. -
Wafer fragment 10 c is shown at a processing step subsequent to that depicted byFIG. 1 (however preferably with no chlorine provided in the gate oxide layer). The gate oxide material oflayer 16 c is etched substantially selective relative to silicon to remove oxide thereover, as shown. A layer of oxide to be used for spacer formation is thereafter deposited oversubstrate 12 and gate construction 18 c. Such is anisotropically etched to forminsulative sidewall spacers 44 proximate opposinglateral edges gate 18. Preferably as shown, such spacers are formed to cover less than all of the conductive material oflateral edges gate 18. Further in this depicted embodiment,such spacers 44 do not overlie any gate oxide material oversubstrate 12, as such has been completed etched away. -
Spacers 44 are provided to be doped with at least one of chlorine or fluorine, with an example dopant concentration being 1×1021 atoms/cm3. Such doping could be provided in any of a number of ways. For example, the deposited insulating layer from which spacers 44 are formed, for example SiO2, could be in situ doped during its formation to provide the desired fluorine and/or chlorine concentration. Alternately, such could be gas diffusion doped after formation of such layer, either before or after the anisotropic etch to form the spacers. Further alternately, and by way of example only, ion implanting could be conducted to provide a desired dopant concentration withinspacers 44. - Referring to
FIG. 5 ,spacers 44 are annealed at a temperature and for a time period effective to diffuse the dopant fluorine or chlorine from such spacers intogate oxide layer 16 c beneathgate 18. Sample annealing conditions are as described above with respect to repair of ion implantation damage. Such can be conducted as a dedicated anneal, or as a byproduct of subsequent wafer processing wherein such conditions are inherently provided. Such provides the illustratedconcentration regions 46 proximate lateral edges 26 and 28 with gate oxide material therebetween preferably being substantially undoped with either chlorine or fluorine. - Referring to
FIG. 6 , another layer of insulating material (i.e., silicon nitride or silicon dioxide) is deposited overgate 18 andsidewall spacers 44. Such is anisotropically etched to formspacers 48 aboutspacers 44 andgate construction 18. Preferably,such spacer 48 formation occurs after annealing to cause effective diffusion doping fromspacers 44 intogate oxide layer 16 c. - Alternate processing with respect to
FIG. 5 is shown inFIG. 7 . Like numerals from the first described embodiment are utilized where appropriate with differences being indicated with the suffix “d”. Here in awafer fragment 10 d, dopedspacers 44 have been stripped from the substrate prior to provision ofspacers 48. Accordingly, diffusion doping of chlorine or fluorine fromspacers 44 would be conducted prior to such stripping in this embodiment. TheFIG. 7 processing is believed to be preferred to that ofFIG. 6 , such that the chlorine or fluorine dopant atoms won't have any adverse effect on later or other processing steps in ultimate device operation or fabrication. For example, chlorine and fluorine may not be desired in the preferred polysilicon material of the gate. - A next alternate embodiment is described with reference to
FIGS. 8 and 9 . Like numerals from the first described embodiment are utilized where appropriate, with differences being indicated with the suffix “e” or with different numerals.FIG. 8 illustrates awafer fragment 10 e which is similar to that depicted byFIG. 4 with the exception thatgate oxide layer 16 e has not been stripped or etched laterally outward of gate edges 26 and 28 prior tospacer 44 e formation. Accordingly in such embodiment, spacers 44 e are formed to overliegate oxide layer 16 e. - Referring to
FIG. 9 , such spacers are subjected to appropriate annealing conditions as described above to cause diffusion doping of the chlorine or fluorine into thegate oxide layer 16 e and beneathgate 18 from laterally outward of gate edges 26 and 28. This embodiment is not believed to be as preferred as those depicted byFIGS. 4-7 , in that the dopant must diffuse both initially downwardly intogate oxide layer 16 and then laterally to beneath gate edges 26 and 28. - Yet another alternate embodiment is described with reference to
FIG. 10 . Like numerals from the first described embodiment are utilized where appropriate, with differences being indicated with the suffix “f”.FIG. 10 is similar to theFIGS. 8-9 embodiment. However,gate oxide layer 16 f is etched only partially into laterally outward of gate edges 26 and 28, thus reducing its thickness. Chlorine and/or fluorine dopedspacers 44 f are subsequently formed as described above. A diffusion annealing is then conducted. In comparison to theFIG. 8 embodiment, theFIG. 10 embodiment provides a portion ofgate oxide layer 16 f to be laterally outwardly exposed, such that dopant diffusion to beneath gate edges 26 and 28 is facilitated. - Provision of fluorine and/or chlorine at the edges, with a central region therebetween being substantially void of same, reduces or eliminates any adverse affect chlorine and/or fluorine would have at the center of the gate where hot electron carrier effects are not as prominent.
- The above-described embodiments preferably place doped chlorine or fluorine proximate both gate edges 26 and 28 within the respective gate oxide layers. Alternately, such greater concentration could be provided proximate only one of the gate edges, such as the drain edge where the hot carrier effects are most problematic.
- In compliance with the statute, the invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.
Claims (50)
1. A method of forming a transistor gate comprising:
forming a gate oxide layer over a semiconductive substrate;
providing chlorine within the gate oxide layer; and
forming a gate proximate the gate oxide layer.
2. The method of claim 1 wherein the chlorine is provided after forming the gate.
3. The method of claim 1 wherein the chlorine is provided before forming the gate.
4. The method of claim 1 wherein the chlorine is provided in the gate oxide layer to a concentration of from about 1×1019 atoms/cm3 to about 1×1021 atoms/cm3.
5. The method of claim 1 wherein the gate comprises opposing lateral edges and a central region therebetween, the chlorine being provided within the gate oxide layer to a greater concentration proximate at least one of the gate edges than in the central region.
6. A method of forming a transistor gate comprising:
forming a gate and a gate oxide layer in overlapping relation, the gate having opposing edges and a center therebetween; and
concentrating at least one of chlorine or fluorine in the gate oxide layer within the overlap more proximate at least one of the gate edges than the center.
7. The method of claim 6 wherein the concentrating comprises concentrating fluorine.
8. The method of claim 6 wherein the gate is formed to have a gate width between the edges of 0.25 micron or less, the concentrating forming at least one concentration region in the gate oxide which extends laterally inward from the at least one gate edge no more than about 500 Angstroms.
9. The method of claim 6 wherein the concentrating comprises diffusion doping.
10. The method of claim 6 wherein the concentrating comprises ion implanting.
11. A method of forming a transistor gate comprising:
forming a gate and a gate oxide layer in overlapping relation, the gate having opposing edges and a central region therebetween; and
doping the gate oxide layer within the overlap with at least one of chlorine or fluorine proximate the opposing gate edges and leaving the central region substantially undoped with chlorine and fluorine.
12. The method of claim 11 wherein the doping comprises ion implanting.
13. The method of claim 11 wherein the doping provides a dopant concentration in the gate oxide layer proximate the edges from about 1×1019 atoms/cm3 to about 1×1021 atoms/cm3.
14. A method of forming a transistor gate comprising the following sequential steps:
forming a gate over a gate oxide layer, the gate having opposing edges; and
angle ion implanting at least one of chlorine or fluorine into the gate oxide layer beneath the edges of the gate.
15. The method of claim 14 wherein the angle is between from about 0.5 degrees to about 10 degrees from perpendicular the gate oxide layer.
16. The method of claim 14 further comprising annealing the gate oxide layer after the implanting.
17. A method of forming a transistor gate comprising the following sequential steps:
forming a gate over a gate oxide layer, the gate having opposing lateral edges; and
diffusion doping at least one of chlorine or fluorine into the gate oxide layer beneath the gate from laterally outward of the gate edges.
18. The method of claim 17 wherein the doping provides a dopant concentration in the gate oxide layer proximate the edges from about 1×1019 atoms/cm3 to about 1×1021 atoms/cm3.
19. The method of claim 17 wherein the doping provides a pair of spaced and opposed concentration regions in the gate oxide which extend laterally inward from the gate edges no more than about 500 Angstroms.
20. The method of claim 17 wherein the doping provides a pair of spaced and opposed concentration regions in the gate oxide which extend laterally inward from the gate edges no more than about 500 Angstroms, the concentration regions having an average dopant concentration in the gate oxide layer proximate the edges from about 1×1019 atoms/cm3 to about 1×1021 atoms/cm3.
21. The method of claim 20 wherein the gate oxide layer between the concentration regions is substantially undoped with chlorine and fluorine.
22. A method of forming a transistor gate comprising the following steps:
forming a gate over a gate oxide layer, the gate having opposing lateral edges;
forming sidewall spacers proximate the opposing lateral edges, the sidewall spacers comprising at least one of chlorine or fluorine; and
annealing the spacers at a temperature and for a time period effective to diffuse the fluorine or chlorine from the spacers into the gate oxide layer to beneath the gate.
23. The method of claim 22 wherein after the annealing, stripping the spacers from the edges.
24. The method of claim 22 comprising forming the spacers to cover less than all of the lateral edges.
25. The method of claim 22 comprising forming the spacers to overlie the gate oxide layer.
26. The method of claim 22 comprising forming the spacers to not overlie any of the gate oxide layer.
27. The method of claim 22 further comprising:
depositing a layer of insulating material over the gate and the sidewall spacers; and
anisotropically etching the layer of insulating material to form spacers over the sidewall spacers.
28. The method of claim 27 wherein the annealing occurs before the depositing.
29. The method of claim 27 wherein the annealing occurs after the depositing.
30. The method of claim 22 further comprising:
providing gate oxide layer material laterally outward of the gate edges;
etching only partially into the gate oxide layer laterally outward of the gate edges; and
forming said sidewall spacers over the etched gate oxide layer laterally outward of the gate edges.
31. A transistor comprising:
a semiconductive material and a transistor gate having gate oxide positioned therebetween, the gate having opposing gate edges and a central region therebetween;
a source formed laterally proximate one of the gate edges and a drain formed laterally proximate the other of the gate edges; and
chlorine within the gate oxide layer between the semiconductive material and the transistor gate.
32. The transistor of claim 31 wherein the chlorine is provided in the gate oxide layer to a concentration of from about 1×1019 atoms/cm3 to about 1×1021 atoms/cm3.
33. The transistor of claim 31 wherein the chlorine is provided within the gate oxide layer to a greater concentration proximate at least one of the gate edges than in the central region.
34. The transistor of claim 31 wherein the chlorine is provided within the gate oxide layer to a greater concentration proximate the other gate edge than in the central region.
35. The transistor of claim 31 wherein the chlorine is provided within the gate oxide layer to a greater concentration proximate both gate edges than in the central region.
36. The transistor of claim 31 wherein the central region is substantially void of chlorine.
37. A transistor comprising:
a semiconductive material and a transistor gate having gate oxide positioned therebetween, the gate having opposing gate edges and a central region therebetween;
a source formed laterally proximate one of the gate edges and a drain formed laterally proximate the other of the gate edges; and
at least one of fluorine or chlorine being concentrated in the gate oxide layer between the semiconductive material and the transistor gate more proximate at least one of the gate edges than the central region.
38. The transistor of claim 37 wherein fluorine is concentrated.
39. The transistor of claim 37 wherein chlorine is concentrated.
40. The transistor of claim 37 wherein the central region of the gate oxide layer is substantially void of chlorine and fluorine.
41. The transistor of claim 37 wherein the concentrated chlorine or fluorine is provided in the gate oxide layer to a concentration of from about 1×1019 atoms/cm3 to about 1×1021 atoms/cm3.
42. The transistor of claim 37 wherein the concentrated chlorine or fluorine is provided in the gate oxide layer to a concentration of from about 1×1019 atoms/cm3 to about 1×1021 atoms/cm3, and wherein the central region of the gate oxide layer is substantially void of chlorine and fluorine.
43. The transistor of claim 37 wherein the at least one of fluorine or chlorine is concentrated in the gate oxide layer more proximate both gate edges than in the central region.
44. The transistor of claim 37 wherein the at least one of fluorine or chlorine is concentrated in the gate oxide layer more proximate at least the other gate edge.
45. The transistor of claim 37 wherein the gate is formed to have a gate width between the edges of 0.25 micron or less, the concentrated at least one of fluorine or chlorine extending laterally inward from the at least one gate edge no more than about 500 Angstroms.
46. The transistor of claim 37 wherein the gate is formed to have a gate width between the edges of 0.25 micron or less, the concentrated at least one of fluorine or chlorine extending laterally inward from the at least one gate edge no more than about 500 Angstroms with an average concentration of from about 1×1019 atoms/cm3 to about 1×1021 atoms/cm3.
47. A transistor comprising:
a semiconductive material and a transistor gate having gate oxide positioned therebetween, the gate having opposing gate edges;
a source formed laterally proximate one of the gate edges and a drain formed laterally proximate the other of the gate edges;
first insulative spacers formed proximate the gate edges, the first insulative spacers being doped with at least one of chlorine or fluorine; and
second insulative spacers formed over the first insulative spacers.
48. The transistor of claim 47 wherein the second insulative spacers at least as initially provided are substantially undoped with either chlorine or fluorine.
49. The transistor of claim 47 further comprising at least one of chlorine or fluorine within the gate oxide layer proximate the gate edges.
50. The transistor of claim 47 wherein the gate oxide layer includes a central region between the opposing gate edges, and further comprising at least one of chlorine or fluorine within the gate oxide layer proximate the gate edges, the central region being substantially void of chlorine and fluorine.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/519,243 US20070020868A1 (en) | 1997-12-18 | 2006-09-11 | Semiconductor processing method and field effect transistor |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US99366397A | 1997-12-18 | 1997-12-18 | |
US09/292,132 US7105411B1 (en) | 1997-12-18 | 1999-04-14 | Methods of forming a transistor gate |
US11/519,243 US20070020868A1 (en) | 1997-12-18 | 2006-09-11 | Semiconductor processing method and field effect transistor |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/292,132 Continuation US7105411B1 (en) | 1997-12-18 | 1999-04-14 | Methods of forming a transistor gate |
Publications (1)
Publication Number | Publication Date |
---|---|
US20070020868A1 true US20070020868A1 (en) | 2007-01-25 |
Family
ID=36951749
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/292,132 Expired - Fee Related US7105411B1 (en) | 1997-12-18 | 1999-04-14 | Methods of forming a transistor gate |
US11/519,243 Abandoned US20070020868A1 (en) | 1997-12-18 | 2006-09-11 | Semiconductor processing method and field effect transistor |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/292,132 Expired - Fee Related US7105411B1 (en) | 1997-12-18 | 1999-04-14 | Methods of forming a transistor gate |
Country Status (1)
Country | Link |
---|---|
US (2) | US7105411B1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10468531B2 (en) | 2010-05-20 | 2019-11-05 | Semiconductor Energy Laboratory Co., Ltd. | Semiconductor device and manufacturing method of the same |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5145672B2 (en) * | 2006-02-27 | 2013-02-20 | 富士通セミコンダクター株式会社 | Manufacturing method of semiconductor device |
FR2981090B1 (en) * | 2011-10-10 | 2014-03-14 | Commissariat Energie Atomique | PROCESS FOR PREPARING P-TYPE ZINC ZNO OXIDE OR P-TYPE ZNMGO OXIDE |
US8828834B2 (en) | 2012-06-12 | 2014-09-09 | Globalfoundries Inc. | Methods of tailoring work function of semiconductor devices with high-k/metal layer gate structures by performing a fluorine implant process |
US9263270B2 (en) | 2013-06-06 | 2016-02-16 | Globalfoundries Inc. | Method of forming a semiconductor device structure employing fluorine doping and according semiconductor device structure |
Citations (28)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3933530A (en) * | 1975-01-28 | 1976-01-20 | Rca Corporation | Method of radiation hardening and gettering semiconductor devices |
US4949136A (en) * | 1988-06-09 | 1990-08-14 | University Of Connecticut | Submicron lightly doped field effect transistors |
US5225355A (en) * | 1988-02-26 | 1993-07-06 | Fujitsu Limited | Gettering treatment process |
US5243212A (en) * | 1987-12-22 | 1993-09-07 | Siliconix Incorporated | Transistor with a charge induced drain extension |
US5369297A (en) * | 1991-09-05 | 1994-11-29 | Mitsubishi Denki Kabushiki Kaisha | Field effect transistor including silicon oxide film and nitrided oxide film as gate insulator film and manufacturing method thereof |
US5382533A (en) * | 1993-06-18 | 1995-01-17 | Micron Semiconductor, Inc. | Method of manufacturing small geometry MOS field-effect transistors having improved barrier layer to hot electron injection |
US5506178A (en) * | 1992-12-25 | 1996-04-09 | Sony Corporation | Process for forming gate silicon oxide film for MOS transistors |
US5516707A (en) * | 1995-06-12 | 1996-05-14 | Vlsi Technology, Inc. | Large-tilted-angle nitrogen implant into dielectric regions overlaying source/drain regions of a transistor |
US5554871A (en) * | 1994-11-09 | 1996-09-10 | Mitsubishi Denki Kabushiki Kaisha | Semiconductor device having MOS transistor with nitrogen doping |
US5571734A (en) * | 1994-10-03 | 1996-11-05 | Motorola, Inc. | Method for forming a fluorinated nitrogen containing dielectric |
US5599726A (en) * | 1995-12-04 | 1997-02-04 | Chartered Semiconductor Manufacturing Pte Ltd | Method of making a conductive spacer lightly doped drain (LDD) for hot carrier effect (HCE) control |
US5672544A (en) * | 1996-04-22 | 1997-09-30 | Pan; Yang | Method for reducing silicided poly gate resistance for very small transistors |
US5672525A (en) * | 1996-05-23 | 1997-09-30 | Chartered Semiconductor Manufacturing Pte Ltd. | Polysilicon gate reoxidation in a gas mixture of oxygen and nitrogen trifluoride gas by rapid thermal processing to improve hot carrier immunity |
US5705409A (en) * | 1995-09-28 | 1998-01-06 | Motorola Inc. | Method for forming trench transistor structure |
US5710450A (en) * | 1994-12-23 | 1998-01-20 | Intel Corporation | Transistor with ultra shallow tip and method of fabrication |
US5714788A (en) * | 1995-12-27 | 1998-02-03 | Chartered Semiconductor Manufacturing, Pte Ltd. | Dual ion implantation process for gate oxide improvement |
US5716875A (en) * | 1996-03-01 | 1998-02-10 | Motorola, Inc. | Method for making a ferroelectric device |
US5721170A (en) * | 1994-08-11 | 1998-02-24 | National Semiconductor Corporation | Method of making a high-voltage MOS transistor with increased breakdown voltage |
US5726479A (en) * | 1995-01-12 | 1998-03-10 | Matsushita Electric Industrial Co., Ltd. | Semiconductor device having polysilicon electrode minimization resulting in a small resistance value |
US5750435A (en) * | 1995-07-26 | 1998-05-12 | Chartered Semiconductor Manufacturing Company Ltd. | Method for minimizing the hot carrier effect in N-MOSFET devices |
US5763312A (en) * | 1997-05-05 | 1998-06-09 | Vanguard International Semiconductor Corporation | Method of fabricating LDD spacers in MOS devices with double spacers and device manufactured thereby |
US5807771A (en) * | 1996-06-04 | 1998-09-15 | Raytheon Company | Radiation-hard, low power, sub-micron CMOS on a SOI substrate |
US5840610A (en) * | 1997-01-16 | 1998-11-24 | Advanced Micro Devices, Inc. | Enhanced oxynitride gate dielectrics using NF3 gas |
US5851890A (en) * | 1997-08-28 | 1998-12-22 | Lsi Logic Corporation | Process for forming integrated circuit structure with metal silicide contacts using notched sidewall spacer on gate electrode |
US5923949A (en) * | 1997-03-21 | 1999-07-13 | Advanced Micro Devices | Semiconductor device having fluorine bearing sidewall spacers and method of manufacture thereof |
US5966623A (en) * | 1995-10-25 | 1999-10-12 | Eastman Kodak Company | Metal impurity neutralization within semiconductors by fluorination |
US6004852A (en) * | 1997-02-11 | 1999-12-21 | United Microelectronics Corp. | Manufacture of MOSFET having LDD source/drain region |
US6087239A (en) * | 1996-11-22 | 2000-07-11 | Micron Technology, Inc. | Disposable spacer and method of forming and using same |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01272161A (en) | 1987-07-14 | 1989-10-31 | Oki Electric Ind Co Ltd | Manufacture of mos type fet |
JPH02173611A (en) | 1988-12-27 | 1990-07-05 | Hitachi Cable Ltd | Kaleidoscope |
JPH0462974A (en) | 1990-06-30 | 1992-02-27 | Fuji Xerox Co Ltd | Mos field-effect transistor and manufacture thereof |
JPH05102067A (en) | 1991-10-11 | 1993-04-23 | Fujitsu Ltd | Manufacture of semiconductor device |
JP2842491B2 (en) | 1992-03-06 | 1999-01-06 | 日本電気株式会社 | Method for manufacturing semiconductor device |
JPH0851108A (en) | 1994-05-31 | 1996-02-20 | Kawasaki Steel Corp | Semiconductor device and manufacture thereof |
JP3266433B2 (en) | 1994-12-22 | 2002-03-18 | 三菱電機株式会社 | Method for manufacturing semiconductor device |
JP3811518B2 (en) | 1995-01-12 | 2006-08-23 | 松下電器産業株式会社 | Semiconductor device and manufacturing method thereof |
JPH08213605A (en) | 1995-02-06 | 1996-08-20 | Oki Electric Ind Co Ltd | Method of manufacturing mos transistor |
JPH09252117A (en) | 1996-03-14 | 1997-09-22 | Sanyo Electric Co Ltd | Field-effect transistor |
-
1999
- 1999-04-14 US US09/292,132 patent/US7105411B1/en not_active Expired - Fee Related
-
2006
- 2006-09-11 US US11/519,243 patent/US20070020868A1/en not_active Abandoned
Patent Citations (30)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3933530A (en) * | 1975-01-28 | 1976-01-20 | Rca Corporation | Method of radiation hardening and gettering semiconductor devices |
US5243212A (en) * | 1987-12-22 | 1993-09-07 | Siliconix Incorporated | Transistor with a charge induced drain extension |
US5225355A (en) * | 1988-02-26 | 1993-07-06 | Fujitsu Limited | Gettering treatment process |
US4949136A (en) * | 1988-06-09 | 1990-08-14 | University Of Connecticut | Submicron lightly doped field effect transistors |
US5369297A (en) * | 1991-09-05 | 1994-11-29 | Mitsubishi Denki Kabushiki Kaisha | Field effect transistor including silicon oxide film and nitrided oxide film as gate insulator film and manufacturing method thereof |
US5506178A (en) * | 1992-12-25 | 1996-04-09 | Sony Corporation | Process for forming gate silicon oxide film for MOS transistors |
US5382533A (en) * | 1993-06-18 | 1995-01-17 | Micron Semiconductor, Inc. | Method of manufacturing small geometry MOS field-effect transistors having improved barrier layer to hot electron injection |
US5721170A (en) * | 1994-08-11 | 1998-02-24 | National Semiconductor Corporation | Method of making a high-voltage MOS transistor with increased breakdown voltage |
US5571734A (en) * | 1994-10-03 | 1996-11-05 | Motorola, Inc. | Method for forming a fluorinated nitrogen containing dielectric |
US5554871A (en) * | 1994-11-09 | 1996-09-10 | Mitsubishi Denki Kabushiki Kaisha | Semiconductor device having MOS transistor with nitrogen doping |
US5710450A (en) * | 1994-12-23 | 1998-01-20 | Intel Corporation | Transistor with ultra shallow tip and method of fabrication |
US5726479A (en) * | 1995-01-12 | 1998-03-10 | Matsushita Electric Industrial Co., Ltd. | Semiconductor device having polysilicon electrode minimization resulting in a small resistance value |
US5516707A (en) * | 1995-06-12 | 1996-05-14 | Vlsi Technology, Inc. | Large-tilted-angle nitrogen implant into dielectric regions overlaying source/drain regions of a transistor |
US5750435A (en) * | 1995-07-26 | 1998-05-12 | Chartered Semiconductor Manufacturing Company Ltd. | Method for minimizing the hot carrier effect in N-MOSFET devices |
US5705409A (en) * | 1995-09-28 | 1998-01-06 | Motorola Inc. | Method for forming trench transistor structure |
US5966623A (en) * | 1995-10-25 | 1999-10-12 | Eastman Kodak Company | Metal impurity neutralization within semiconductors by fluorination |
US5831319A (en) * | 1995-12-04 | 1998-11-03 | Chartered Semiconductor | Conductive spacer lightly doped drain (LDD) for hot carrier effect (HCE) control |
US5599726A (en) * | 1995-12-04 | 1997-02-04 | Chartered Semiconductor Manufacturing Pte Ltd | Method of making a conductive spacer lightly doped drain (LDD) for hot carrier effect (HCE) control |
US5714788A (en) * | 1995-12-27 | 1998-02-03 | Chartered Semiconductor Manufacturing, Pte Ltd. | Dual ion implantation process for gate oxide improvement |
US5716875A (en) * | 1996-03-01 | 1998-02-10 | Motorola, Inc. | Method for making a ferroelectric device |
US5672544A (en) * | 1996-04-22 | 1997-09-30 | Pan; Yang | Method for reducing silicided poly gate resistance for very small transistors |
US5672525A (en) * | 1996-05-23 | 1997-09-30 | Chartered Semiconductor Manufacturing Pte Ltd. | Polysilicon gate reoxidation in a gas mixture of oxygen and nitrogen trifluoride gas by rapid thermal processing to improve hot carrier immunity |
US5814863A (en) * | 1996-05-23 | 1998-09-29 | Chartered Semiconductor Manufacturing Company, Ltd. | Substrate with gate electrode polysilicon/gate oxide stack covered with fluorinated silicon oxide layer and fluorinated corners of gate oxide layer |
US5807771A (en) * | 1996-06-04 | 1998-09-15 | Raytheon Company | Radiation-hard, low power, sub-micron CMOS on a SOI substrate |
US6087239A (en) * | 1996-11-22 | 2000-07-11 | Micron Technology, Inc. | Disposable spacer and method of forming and using same |
US5840610A (en) * | 1997-01-16 | 1998-11-24 | Advanced Micro Devices, Inc. | Enhanced oxynitride gate dielectrics using NF3 gas |
US6004852A (en) * | 1997-02-11 | 1999-12-21 | United Microelectronics Corp. | Manufacture of MOSFET having LDD source/drain region |
US5923949A (en) * | 1997-03-21 | 1999-07-13 | Advanced Micro Devices | Semiconductor device having fluorine bearing sidewall spacers and method of manufacture thereof |
US5763312A (en) * | 1997-05-05 | 1998-06-09 | Vanguard International Semiconductor Corporation | Method of fabricating LDD spacers in MOS devices with double spacers and device manufactured thereby |
US5851890A (en) * | 1997-08-28 | 1998-12-22 | Lsi Logic Corporation | Process for forming integrated circuit structure with metal silicide contacts using notched sidewall spacer on gate electrode |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10468531B2 (en) | 2010-05-20 | 2019-11-05 | Semiconductor Energy Laboratory Co., Ltd. | Semiconductor device and manufacturing method of the same |
Also Published As
Publication number | Publication date |
---|---|
US7105411B1 (en) | 2006-09-12 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7189623B2 (en) | Semiconductor processing method and field effect transistor | |
US6245618B1 (en) | Mosfet with localized amorphous region with retrograde implantation | |
US5851893A (en) | Method of making transistor having a gate dielectric which is substantially resistant to drain-side hot carrier injection | |
JP3977013B2 (en) | CMOS process with removable sidewall spacers for individually optimized N-channel and P-channel transistor performance | |
US5895955A (en) | MOS transistor employing a removable, dual layer etch stop to protect implant regions from sidewall spacer overetch | |
US6660658B2 (en) | Transistor structures, methods of incorporating nitrogen into silicon-oxide-containing layers; and methods of forming transistors | |
EP0495650B1 (en) | Method of fabricating field-effect transistor | |
US7485516B2 (en) | Method of ion implantation of nitrogen into semiconductor substrate prior to oxidation for offset spacer formation | |
US6180476B1 (en) | Dual amorphization implant process for ultra-shallow drain and source extensions | |
US8318571B2 (en) | Method for forming P-type lightly doped drain region using germanium pre-amorphous treatment | |
JP2735486B2 (en) | Method of manufacturing MOSFET | |
KR100718823B1 (en) | A silicon-germanium transistor and associated methods | |
US20070020868A1 (en) | Semiconductor processing method and field effect transistor | |
US6977205B2 (en) | Method for manufacturing SOI LOCOS MOSFET with metal oxide film or impurity-implanted field oxide | |
KR970004484B1 (en) | Fabrication method of ldd mosfet | |
KR100574172B1 (en) | Method for fabricating semiconductor device | |
US20070105295A1 (en) | Method for forming lightly-doped-drain metal-oxide-semiconductor (LDD MOS) device | |
US20070004114A1 (en) | Sacrificial capping layer for transistor performance enhancement | |
US6887759B2 (en) | LDD-type miniaturized MOS transistors | |
JP2703883B2 (en) | MIS transistor and method of manufacturing the same | |
KR100280105B1 (en) | Manufacturing Method of Semiconductor Device | |
US6936517B2 (en) | Method for fabricating transistor of semiconductor device | |
JPH08298318A (en) | Manufacture of semiconductor device | |
KR20050055125A (en) | Method for fabricating mosfet |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |