CN102637798A

CN102637798A - Light emitting diode (LED) structure and manufacture method of LED structure

Info

Publication number: CN102637798A
Application number: CN2011100373342A
Authority: CN
Inventors: 吴东海; 李志翔
Original assignee: TONGFANG OPTO-ELECTRONIC Co Ltd
Current assignee: TONGFANG OPTO-ELECTRONIC Co Ltd
Priority date: 2011-02-14
Filing date: 2011-02-14
Publication date: 2012-08-15

Abstract

The invention provides a light emitting diode (LED) structure and a manufacture method of the LED structure and belongs to the technical field of photoelectricity. The LED structure comprises a substrate structure and a luminous structure, wherein the luminous structure grows on the surface of the substrate in an epitaxial way and comprises an N type semiconductor layer, a luminous layer and a P type semiconductor layer sequentially formed on the substrate, an N type ohm contact electrode is arranged on the N type semiconductor layer, and a P type ohm contact electrode is arranged on the P type semiconductor layer. The LED structure is structurally characterized in that the upper surface of the substrate is corroded to form irregular concave part and convex part surfaces, and the concave parts and the convex parts of the upper surface of the substrate are fully filled by the N type semiconductor layer in the epitaxial growth process. Through the formation of the irregular concave-convex structures on the surface of the substrate, the inner quantum efficiency and the light extraction efficiency are improved, the optical performance of the device is improved, and the LED structure has the characteristics that the process is simple, the manufacture cost is low, and the LED structure is applicable to the mass volume production.

Description

A kind of light emitting diode construction and preparation method thereof

Technical field

The present invention relates to field of photoelectric technology, particularly can improve light emitting diode construction of internal quantum efficiency and external quantum efficiency and preparation method thereof.

Background technology

With the GaN material is the III-V hi-nitride semiconductor material of representative, at UV/blue/green light LED, laser, photodetector, and has a wide range of applications in high temperature high-frequency high-power field of electronic devices.Because material bodies monocrystalline such as GaN and AlN are difficult to obtain; At present the nitride device of widespread usage mainly be heteroepitaxy on sapphire Al2O3, carborundum SiC, silicon Si, zinc oxide ZnO or GaAs GaAs substrate, or isoepitaxial growth is on self-standing gan GaN substrate.

Except the self-standing gan substrate; All there are the very big lattice constant mismatch and the difference of thermal coefficient of expansion between other backing material and the III-V group nitride material; The difference of lattice constant and thermal coefficient of expansion; Make to have very big residual stress and many crystal defects in the nitride epitaxial layer, had a strong impact on the crystal mass of material, and then limited the raising of III-V nitride devices performance.In addition; For the iii-nitride light emitting devices device, owing to there is bigger refractive index difference between gallium nitride GaN and air, the angle of emergence of light is very little; Overwhelming majority light are got back to the inside of LED device by total reflection, and this has not only reduced the extraction efficiency of light but also increased the difficulty of heat radiation.In order to solve the problem that lattice mismatch in the nitride material epitaxial process and thermal mismatching are brought, people have proposed a series of comparatively mature technique scheme.Wherein, The patterned substrate technology can effectively be alleviated in substrate and the nitride epitaxial layer heteroepitaxial growth process because the stress that lattice mismatch brings; Make epitaxial loayer obtain effective relaxation, adopt lateral growth technology (Epitaxial Lateral Overgrowth simultaneously; ELOG) and laterally build brilliant method (Lateral Epitaxial Pattern Substrate; LEPS) reduce threading dislocation density in the epitaxial loayer, thereby reduce the defect concentration in the nitride epitaxial layer material, improved the crystal mass of material, like U.S. Patent No. US 6,870,193, CN 1209793C.The patterned substrate technology also is a method that can effectively promote iii-nitride light emitting devices device luminous efficiency simultaneously; In U.S. Pat 6; In 870, the 193 disclosed technology, said light-emitting component is a kind of semiconductor light-emitting elements on the substrate that is formed at that possesses recess or protuberance structure; Compare with the flat substrate situation; The light of this kind structure is when the horizontal transmission of semiconductor layer, and photoetching is through the effect of recess or protuberance generation scattering or diffraction, the light extraction efficiency of light-emitting diode significantly.

In the prior art; The making of patterned substrate mostly adopts traditional photoetching technique to prepare litho pattern; Then with photoresist, silicon dioxide SiO2, silicon nitride SiN or metal Ni layer as mask, utilize the method for dry etching or wet etching that substrate etching is gone out patterned structures again.But above-mentioned complex technical process significantly increases cost, and figure receives the restriction of lithography layout, and the utmost point is not suitable for the commercial application of nitride compound semiconductor device.

Summary of the invention

In order to overcome the deficiency that above-mentioned prior art exists, the purpose of this invention is to provide a kind of light emitting diode construction and manufacturing approach thereof.It improves internal quantum efficiency and light extraction efficiency through form irregular concaveconvex structure at substrate surface, improves the optical property of device, and it is simple to have technology, and cost of manufacture is low, is applicable to the characteristics of scale of mass production.

In order to reach the foregoing invention purpose, technical scheme of the present invention realizes as follows:

A kind of light emitting diode construction, it comprises substrate and is epitaxially grown in the ray structure on the substrate surface.Ray structure comprises n type semiconductor layer, luminescent layer and the p type semiconductor layer that is formed at successively on the substrate.N type semiconductor layer is provided with N type Ohm contact electrode, and p type semiconductor layer is provided with P type Ohm contact electrode.Its design feature is, said substrate top surface is corroded, and to form irregular recess surperficial with protuberance, and n type semiconductor layer fills up the recess and the protuberance of substrate top surface in epitaxial process.

In above-mentioned light emitting diode construction, said substrate adopts sapphire Al2O3, carborundum SiC, silicon Si, GaAs GaAs, aluminium nitride AlN or gallium nitride GaN substrate.

A kind of manufacture method of light emitting diode construction, it comprises the steps:

puts into reaction cavity with substrate;

feeds corrosive gas substrate corroded in reaction cavity, make substrate top surface form irregular recess and protuberance surface;

takes out substrate in reaction cavity, and cleans substrate surface;

forms ray structure on substrate surface; Ray structure comprises n type semiconductor layer, luminescent layer and the p type semiconductor layer that is formed at successively on this substrate; N type semiconductor layer is provided with N type Ohm contact electrode, and p type semiconductor layer is provided with P type Ohm contact electrode.

In above-mentioned manufacture method, said reaction cavity adopts metallorganic chemical vapor deposition cavity, molecular beam epitaxy cavity, hydride gas-phase epitaxy cavity or special special pyroreaction cavity.

In above-mentioned manufacture method, said corrosive gas adopts HCl.

In above-mentioned manufacture method, the size of said irregular recess and protuberance structure is controlled through the temperature that changes reaction cavity, the feeding flow and the time parameter of corrosive gas.

In above-mentioned manufacture method, the dry method cleaning of the wet-cleaned of said cleaning substrate surface employing washed with de-ionized water or plasma clean, inert gas purge.

The present invention has been owing to adopted said structure and method, through with corrosive gas to substrate etching, after substrate surface forms irregular concaveconvex structure, can be on substrate surface the heteroepitaxy nitride semi-conductor material.Can utilize lateral growth technology and brilliant method laterally of heap of stone to reduce the defect concentration in the nitride epitaxial layer, improve internal quantum efficiency, and then improve device performance.Concaveconvex structure through substrate surface can produce scattering and diffraction effect to the light of LED device inside in addition, reduces the total reflection odds, improves the light extraction efficiency of LED device.The substrate surface method of roughening that the present invention proposes, technology is simple, and cost of manufacture is low, is specially adapted to scale of mass production.

For making technical scheme of the present invention and characteristics clearer, the present invention is made further detailed description below in conjunction with accompanying drawing and embodiment.

Description of drawings

Fig. 1 to Fig. 4 is a manufacture method step sketch map of the present invention;

Fig. 4 also is a light-emitting diode structure sketch map of the present invention.

Embodiment

Referring to Fig. 4, the ray structure that light emitting diode construction of the present invention comprises substrate 10 and is epitaxially grown in substrate 10 surfaces.Substrate 10 adopts sapphire Al2O3, carborundum SiC, silicon Si, GaAs GaAs, aluminium nitride AlN or gallium nitride GaN substrate.Ray structure comprises n type semiconductor layer 21, luminescent layer 22 and the p type semiconductor layer 23 that is formed at successively on the substrate 10.N type semiconductor layer 21 is provided with N type

Ohm contact electrode

210, and 23 are provided with P type Ohm contact electrode 230 on the p type semiconductor layer.Substrate 10 upper surfaces are corroded and form irregular recess 11 and protuberance 12 surfaces, and n type semiconductor layer 21 fills up the recess 11 of substrate 10 upper surfaces in epitaxial process with protuberance 12.

Referring to Fig. 1 to Fig. 4, for the manufacture method of light emitting diode construction of the present invention comprises:

puts into reaction cavity 3 with substrate 10; Substrate 10 adopts sapphire Al2O3, carborundum SiC, silicon Si, GaAs GaAs, aluminium nitride AlN or gallium nitride GaN substrate, and reaction cavity 3 adopts metallorganic chemical vapor deposition cavity, molecular beam epitaxy cavity, hydride gas-phase epitaxy cavity or special special pyroreaction cavity.

feeds 4 pairs of substrates 10 of corrosive gas and corrodes in reaction cavity 3; Make substrate 10 upper surfaces form a plurality of irregular recesses 11 and protuberance 12, this corrosive gas 4 preferred gas HCl that easily substrate 10 formed corrosion.Irregular recess 11 is controlled through the temperature that changes reaction cavity 3, flow and the time parameter that corrosive gas 4 feeds with the size of protuberance 12 structures.

takes out substrate 10 in reaction cavity 3, and cleans substrate 10 surfaces.The dry method cleaning of the wet-cleaned of cleaning substrate 10 surface employing washed with de-ionized water or plasma clean, inert gas purge.

goes up in substrate 10 surfaces and forms ray structure; Ray structure comprises n type semiconductor layer 21, luminescent layer 22 and the p type semiconductor layer 23 that is formed at successively on this substrate 10; N type semiconductor layer 21 is provided with N type Ohm contact electrode 210; P type semiconductor layer 23 is provided with P type Ohm contact electrode 230, with thinking that this ray structure provides voltage.

The above is merely a specific embodiment of the present invention, is not limited to the present invention, and is all within technology path of the present invention, and any modification, replacement or the improvement made also all should be included within protection scope of the present invention.

Claims

1. light emitting diode construction; It comprises substrate (10) and is epitaxially grown in the lip-deep ray structure of substrate (10); Ray structure comprises n type semiconductor layer (21), luminescent layer (22) and the p type semiconductor layer (23) that is formed at successively on the substrate (10); N type semiconductor layer (21) is provided with N type Ohm contact electrode (210); (23) are provided with P type Ohm contact electrode (230) on the p type semiconductor layer; It is characterized in that said substrate (10) upper surface is corroded and forms irregular recess (11) and protuberance (12) surface, n type semiconductor layer (21) fills up the recess (11) of substrate (10) upper surface in epitaxial process with protuberance (12).

2. light emitting diode construction according to claim 1 is characterized in that, said substrate (10) adopts sapphire Al2O3, carborundum SiC, silicon Si, GaAs GaAs, aluminium nitride AlN or gallium nitride GaN substrate.

3. the manufacture method of a light emitting diode construction, it comprises the steps:

puts into reaction cavity (3) with substrate (10);

feeds corrosive gas (4) substrate (10) corroded in reaction cavity (3), make substrate (10) upper surface form irregular recess (11) and protuberance (12) surface;

takes out substrate (10) in reaction cavity (3), and cleans substrate (10) surface;

forms ray structure on substrate (10) surface; Ray structure comprises n type semiconductor layer (21), luminescent layer (22) and the p type semiconductor layer (23) that is formed at successively on this substrate (10); N type semiconductor layer (21) is provided with N type Ohm contact electrode (210), and p type semiconductor layer (23) is provided with P type Ohm contact electrode (230).

4. the manufacture method of light emitting diode construction according to claim 3; It is characterized in that said reaction cavity (3) adopts metallorganic chemical vapor deposition cavity, molecular beam epitaxy cavity, hydride gas-phase epitaxy cavity or special special pyroreaction cavity.

5. according to the manufacture method method of claim 3 or 4 described light emitting diode constructions, it is characterized in that said corrosive gas (4) adopts HCl.

6. the manufacture method of light emitting diode construction according to claim 5; It is characterized in that said irregular recess (11) is controlled through the temperature that changes reaction cavity (3), the feeding flow and the time parameter of corrosive gas (4) with the size of protuberance (12) structure.

7. the manufacture method of light emitting diode construction according to claim 6 is characterized in that, the dry method cleaning of the wet-cleaned of said cleaning substrate (10) surface employing washed with de-ionized water or plasma clean, inert gas purge.