WO2015124549A1

WO2015124549A1 - Semiconductor device and method for applying a coating onto multiple semiconductor devices

Info

Publication number: WO2015124549A1
Application number: PCT/EP2015/053275
Authority: WO
Inventors: Michael Stockmeier; Michael Schmal; Thomas Veit; Tomasz Swietlik
Original assignee: Osram Opto Semiconductors Gmbh
Priority date: 2014-02-18
Filing date: 2015-02-17
Publication date: 2015-08-27
Also published as: DE102014102037A1

Abstract

The invention relates to a semiconductor device (10) comprising a semiconductor body (3) which has a first contact layer (1) on a first main surface (11) and a second contact layer (2) on a second main surface (12). The semiconductor body (3) has a depression (4) on the first main surface (11), and the depression is spaced from each of two opposing lateral surfaces (5, 6) of the semiconductor body (3), said first contact layer (1) being completely arranged in the depression (4). The second contact layer (2) has an equal or greater distance to the opposing lateral surfaces (5, 6) than the depression (4). The invention further relates to a method for applying a coating (7, 8) onto multiple semiconductor devices (10a, 10b, 10c, 10d).

Description

description

A semiconductor device and method for applying a coating to a plurality of semiconductor devices

The invention relates to a semiconductor device,

in particular an optoelectronic component such as

For example, a semiconductor laser, and a method for applying a coating to a plurality

Semiconductor devices.

This patent application claims the priority of German Patent Application 102014102037.5, the disclosure of which is hereby incorporated by reference.

Semiconductor devices, in particular optoelectronic

Components such as semiconductor lasers or LEDs typically have a semiconductor body, which is provided for electrical contacting with electrical contact layers. By way of example, the semiconductor body may have an n-side contact layer on a first main area and a p-side contact layer on an opposite second main area. Often, the side surfaces of the semiconductor body, which are perpendicular to the main surfaces, provided with a functional coating. For example, the side surfaces of a

Optoelectronic device provided with a reflection-reducing or a reflection-enhancing coating. For applying a coating on the side surfaces of the semiconductor body, the semiconductor devices

stacked on top of each other and form in this way a so-called coating horde. That's the way it is possible, the side surfaces of a variety of

Coating semiconductor bodies simultaneously. In this approach, however, the problem may arise that arranged on the main surfaces of the semiconductor body

Contact surfaces of adjacent in the stack

Contact semiconductor bodies with each other. This may lead to an adhesion of the contact layers due to the high process temperatures during the coating process and / or due to the applied coating material, so that it is difficult to separate the semiconductor bodies from each other after the coating process. To get a touch of

Contact layers of adjacent semiconductor body in the stack of semiconductor bodies in the coating process to

can spacers between the

Semiconductor devices are inserted, which are referred to as dummy bars in the case of stacked laser bars.

By inserting the spacers can but less for a given size of the layer stack

Semiconductor devices are coated simultaneously.

Furthermore, by inserting the spacers increases the manufacturing cost and there is a risk that impurities in the stack of semiconductor bodies

be introduced.

The invention has for its object to provide an improved semiconductor device whose side surfaces can be coated in a particularly economical manner. Furthermore, a method for applying a

Coating can be specified on several semiconductor devices. These objects are achieved by a semiconductor device and a method according to the independent claims. Advantageous embodiments and further developments of

Invention are the subject of the dependent claims.

The semiconductor device according to at least one

Embodiment, a semiconductor body having a first major surface and a first major surface opposite the second major surface. The semiconductor body can in particular be applied to a substrate

Semiconductor layer sequence, wherein the first

Main surface facing away from the semiconductor layer sequence rear side of the substrate and the second main surface of a substrate opposite surface of the

Semiconductor layer sequence is. In other words, the semiconductor body becomes vertically through the first one

Main area and the opposite second main area limited. In the lateral direction, the semiconductor body is bounded by side surfaces, which are preferably perpendicular to the main surfaces.

The semiconductor device further includes a first one

Contact layer on the first main surface of the

Semiconductor body and a second contact layer on the second main surface of the semiconductor body. The first contact layer and the second contact layer are used for electrical contacting of the semiconductor body, the

For example, it may be an optoelectronic component. The semiconductor body may have, for example, an n-doped semiconductor region and a p-doped semiconductor region, wherein the first contact layer contacts the n-doped semiconductor region and the second contact layer contacts the p-doped semiconductor region. The first Contact layer and the second contact layer can

in particular a metal or a metal alloy. Alternatively, it is possible that the first contact layer and / or the second contact layer comprise a non-metallic electrically conductive material, for. B. a

transparent conductive oxide (TCO) such as ITO.

In the semiconductor device, the semiconductor body advantageously has a recess on the first main surface, which has in each case a spacing from two opposite side surfaces of the semiconductor body. The

In other words, the recess does not directly adjoin any of the opposite side surfaces, so that between the recess and the side surfaces of the

Semiconductor body in each case an edge region of the

Semiconductor body is arranged.

In the semiconductor device, the first contact layer is advantageously arranged completely in the depression. The first contact layer therefore, like the depression, does not adjoin the side surfaces of the semiconductor body, but is spaced from the side surfaces by the edge regions of the semiconductor body which are arranged between the depression and the side surfaces.

The second one arranged on the second main surface

Contact layer has in the semiconductor device

Advantageously from the opposite side surfaces of the semiconductor body at a distance which is greater than or equal to the distance of the recess from the side surfaces. Thus, the second contact layer does not directly adjoin the side surfaces of the semiconductor body, but is as the first contact layer by edge regions of

Semiconductor body spaced from the side surfaces.

Several similar specimens of the one described here

Semiconductor devices can advantageously be stacked on each other such that the first main surface of a

Semiconductor device and the second main surface of an adjacent semiconductor device facing each other, without that the first contact layer of the

Semiconductor device and the second contact layer of the semiconductor device adjacent to each other in the stack. This is achieved in particular in that the first contact layer of the semiconductor device is arranged in a depression of the semiconductor body. In this way, it is advantageously prevented that the first and second contact layers of adjacent semiconductor devices adhere to one another when coating the front sides and / or rear sides by applied coating material. In a preferred embodiment, a vertical projection of the second contact layer lies on the first

Main surface of the semiconductor body completely within the depression. Under a vertical projection is here a projection perpendicular to the main surfaces of the

Semiconductor body to understand. In other words, the second contact layer has the same or a smaller lateral extent than the depression.

Furthermore, the depression preferably has a depth which is greater than the sum of a thickness of the first

Contact layer and a thickness of the second contact layer. Characterized in that the lateral extent of the second contact layer is less than the lateral extent of the recess and the recess has a depth which is greater than the sum of the thicknesses of the first and the second

Contact layer, the recess can advantageously accommodate both the first contact layer and the second contact layer completely. This has the particular advantage that the semiconductor device on the first main surface on the second major surface of a similar

Semiconductor device can be placed, wherein the

Deepening of the semiconductor device and the second

Main surface of the further semiconductor device form a cavity, both the first contact layer of the

Semiconductor device and the second contact layer of the other semiconductor device encloses.

When applying coating material on the front sides and / or back sides of the stacked one another

Semiconductor devices touch the first one

Contact layer of the semiconductor device and the second

Contact layer of the adjacent semiconductor device

advantageously not mutually, so that they could not stick together by a possibly occurring during the coating process high process temperature.

In a preferred embodiment, a front side and / or a rear side of the semiconductor device has a

Coating, wherein the front side and the rear side are preferably perpendicular to the first and second

Main surface and to the side surfaces are. The coating may in particular be a reflection-reducing or a

be reflection-enhancing coating. The coating may for example be a dielectric mirror, the is preferably formed of a plurality of dielectric layers. Alternatively, the coating can also be a

reflection-reducing coating, which is preferably formed of a plurality of dielectric layers. The

Materials and the thicknesses of the dielectric layers are selected in these cases such that a reflection-increasing or reflection-reducing effect is achieved for a desired wavelength, for example for the wavelength of a radiation emitted by a semiconductor laser. The dielectric layers may be, for example

Have oxides, nitrides or fluorides. Furthermore, it is also possible that the coating has one or more

Has metal layers. The semiconductor device is according to a preferred

Design an optoelectronic device, such as

For example, an LED, a photodetector or a

Semiconductor lasers. In particular, the semiconductor device may include

Semiconductor laser, z. As a laser bar, be, wherein the front side and the back of the semiconductor body

Form resonator mirror of the semiconductor laser. In this case, advantageously, the back side of the semiconductor body has a reflection-enhancing coating, which forms the first resonator mirror of the semiconductor laser. An opposite front side of the semiconductor body may be provided as a radiation coupling-out surface of the semiconductor laser and forms the second resonator mirror of the semiconductor body

Semiconductor laser off. The front surface provided as a coupling-out surface can be a reflection-enhancing coating with a lower reflectivity than a coating of the opposite back or have a reflection-reducing coating.

The semiconductor body preferably has a semiconductor layer sequence applied to a substrate. The

Semiconductor layer sequence may in particular have an active layer suitable for the emission of radiation.

By way of example, the semiconductor layer sequence has an n-type semiconductor region, a p-type semiconductor region and an active layer arranged therebetween. Preferably, the n-type semiconductor region is the substrate and the p-type semiconductor region is the second main surface of the semiconductor device

Semiconductor body facing. The first main area of the

Semiconductor body to which the recess in the

Semiconductor body is formed, in particular, a remote from the semiconductor layer sequence surface of the

Be a substrate. The substrate is in particular a

Semiconductor substrate, preferably an n-type semiconductor substrate.

According to a preferred embodiment, the recess has a spacing of at least 50 μm, preferably between 50 μm and 200 μm inclusive, of the

Side surfaces of the semiconductor body. In other words, the edge regions of the semiconductor body which delimit the depression laterally each have a width of at least 50 μm, preferably between 50 μm inclusive and 200 μm inclusive. When stacking a plurality of semiconductor devices, only the edge regions of the semiconductor body are located on the first main surface on the second main surface of the adjacent semiconductor body. In accordance with at least one embodiment of the method for applying a coating to a plurality

Semiconductor devices, the semiconductor devices are stacked such that in each case the first main surface of a semiconductor device and the second main surface of an adjacent semiconductor device facing each other, wherein the recess in the semiconductor body of the

Semiconductor device and the second main surface of the

adjacent semiconductor device include the first contact layer of the semiconductor device and the second contact layer of the adjacent semiconductor device.

A coating is subsequently applied to the front sides and / or back sides of the semiconductor devices stacked in this way. The coating is at the

Advantageously, the method is simultaneously applied to the adjoining front sides and / or rear sides of adjacent semiconductor devices, wherein due to the inclusion of the mutually facing contact layers in the cavity, there is no risk that the contact layers adhere to one another due to applied coating material and / or an increased process temperature during the coating process. The arranged in the stack

Semiconductor devices can therefore after the

Coating process without difficulty be separated again.

In particular, it is advantageously not necessary in the method to insert spacers between the adjacent semiconductor devices in order to prevent sticking of the adjacent contact layers. There no

Spacers may be needed, a stack of

Semiconductor devices about twice as many Semiconductor devices have as an equal size

Stack with spacers between the adjacent ones

Semiconductor devices. The fact that no spacers are introduced between the semiconductor devices, eliminates the risk for the introduction of

Contaminations by the spacers. With the method, the semiconductor devices can therefore be particularly efficient, inexpensive and reliable coated. Further advantageous embodiments of the method will become apparent from the previous description of

Semiconductor device and vice versa.

The invention will be described below with reference to

Embodiments in connection with Figures 1 and 2 explained in more detail.

FIG. 1A shows a schematic representation of a plan view of a semiconductor device according to FIG

Embodiment,

FIG. 1B shows a schematic illustration of a cross section along the line AB of the semiconductor device according to the exemplary embodiment,

FIG. 2A shows a schematic representation of a plan view of a stack of four semiconductor devices in an intermediate step of the method according to FIG

Embodiment, FIG. 2B shows a schematic representation of a cross section along the line CD through the stack of four semiconductor devices in the intermediate step of the method according to the exemplary embodiment,

FIG. 2C shows a schematic representation of a plan view of the stack of four semiconductor devices in a further intermediate step of the method according to the exemplary embodiment, and FIG

Figure 2D is a schematic representation of a cross section along the line EF through the stack of four semiconductor devices in the further intermediate step of the method according to the embodiment.

Identical or equivalent components are each provided with the same reference numerals in the figures. The

Components shown and the proportions of the components with each other are not to be regarded as true to scale.

The in Fig. 1A in a plan view and in Fig. 1B in a cross section along the line AB shown

Semiconductor device 10 according to an embodiment has a semiconductor body 3, which is formed by a semiconductor layer sequence 32 applied to a substrate 31. The substrate 31 may in particular

Semiconductor substrate, for example, a GaAs substrate. The substrate 31 is preferably electrically conductive and may in particular be doped, for example n-doped. The individual layers of the semiconductor layer sequence 32 are not shown individually for the sake of simplicity. The Semiconductor layer sequence 32 may in particular one for

Emission of radiation have suitable active layer. By way of example, the semiconductor layer sequence has an n-type semiconductor region, a p-type semiconductor region and an active layer arranged therebetween.

The semiconductor body has a first main surface 11 and a second main surface 11 opposite the second

Main area 12 up. The first main surface 11 has a

Deepening 4, in which a first contact layer 1 is arranged for electrical contacting of the semiconductor body 3. The recess 4 is in the substrate 31 of the

Semiconductor body 3 is formed. A second contact layer 2 for electrical contacting of the semiconductor body 3 is arranged on the opposite second main surface 12. Preferably, the first contact layer 1 is an n-side

Contact layer and the second contact layer 2, a p-side contact layer. The depression 4 on the first main surface 11 is advantageously at a distance from the side surfaces 5, 6 of the semiconductor body 3. The distance of the recess 4 of the

Side surfaces 5, 6 is preferably at least 50 ym, for example 50 ym to 200 ym. The second contact layer 2 on the opposite second main surface 12 advantageously has an equal or greater distance from the side surfaces 5, 6 than the recess 4. In particular, the second contact layer 2 is designed with respect to its dimensions and its arrangement on the second main surface 12, that is a vertical projection of the second

Contact layer 2 on the first main surface 11, d. H. a projection perpendicular to the major surfaces 11, 12 of the

Semiconductor body 3, completely within the well 4 lies. In other words, the lateral dimensions of the second contact layer 2 are less than or equal to the lateral dimensions of the depression 4. The depression 4 has a depth that is greater than the sum of the thickness of the first contact layer 1 and the thickness of the second

Contact layer 2.

Characterized in that the first contact layer 1 and the second

Contact layer 2 not on the side surfaces 5, 6 of the

Semiconductor body 3 are adjacent, the semiconductor body 3 inactive edge portions 51, 61 which adjoin the side surfaces 5, 6. In the inactive edge regions 51, 61 no current is impressed during operation of the semiconductor device.

Due to the inactive edge regions 51, 61 are the first

Contact layer 1 in the recess 4 and the second

Contact layer 2 from the side surfaces 5, 6 spaced.

In the semiconductor device 10, a front side 15 and a rear side 16 each have a coating 7, 8

applied. The front side 15 and the rear side 16 are each perpendicular to the main surfaces 11, 12 and the

Side surfaces 5, 6. The coatings 7, 8 can

in particular be optical functional layers. The

Semiconductor device 10 is preferably one

optoelectronic component, in particular a

Semiconductor lasers such as a laser bar.

In the case of a semiconductor laser, the front side 15 and rear side 16 of the semiconductor device 10 are provided for forming a laser resonator. The coatings 7, 8 may in particular be reflection-enhancing coatings. Alternatively, it is also possible that at least one of

Coatings 7, 8 as a reflection-reducing coating is executed, for. B. at a radiation decoupling surface of the semiconductor laser. The reflection-enhancing or

reflection-reducing coating 7, 8 may be formed in particular as a dielectric layer system, which may have a plurality of sub-layers. Alternatively, it is also possible that the coatings 7, 8 one or more

Layers of a metal or a metal alloy

exhibit . The semiconductor device 10 has the advantage that the

Coatings 7, 8 particularly economical on the

Front 15 and / or back 16 can be applied. This is illustrated by the method illustrated in FIGS. 2A and 2B for applying a coating to a plurality of semiconductor devices 10a, 10b, 10c, 10d. The

Semiconductor devices 10a, 10b, 10c, 10d in the method described in FIG

Structure and its advantageous embodiments of the im

Related to Figure 1 described semiconductor device 10th

In the intermediate step illustrated in FIG. 2A, four semiconductor devices 10a, 10b, 10c, 10d have been stacked on top of one another so that in each case the second main surface 12 of a semiconductor device 10a faces a first main surface 11 of a further semiconductor device 10b. The recess 4 on the first main surface 11 of the other

Semiconductor device 10b and the second main surface 12 of the semiconductor device 10a together form a cavity 9, which forms the second contact layer 2 of FIG

Semiconductor device 10a and the first contact layer 1 of the other semiconductor device 10b completely encloses. The fact that the depth of the recess is greater than that Sum of the thicknesses of the first contact layer 1 and the second contact layer 2, the cavity 9 encloses both

Contact layers 1, 2, without these touching each other.

In the method step illustrated in FIG. 2B, coatings 7, 8 have been applied to the front sides 15 and the rear sides 16 of the semiconductor devices 10a, 10b, 10c, 10d. Characterized in that the contact layers 1, 2 in the

Cavity 9 between the second main surface 12 and the first main surface 11 of the adjacent semiconductor devices 10a, 10b, 10c, 10d are arranged, the risk that this by an increased process temperature at

Apply the coatings 7, 8 stick together.

To simplify the illustration, only four are arranged one on the other in FIGS. 2A and 2B

Semiconductor devices 10a, 10b, 10c, lOd shown.

In fact, in the practice of the method, however, a plurality of semiconductor devices may be contiguous

be stacked, in which the front sides 15 and / or

Backs 16 are coated at the same time.

In the method, it is advantageously not necessary

insert spacers between the stacked semiconductor devices 10a, 10b, 10c, 10d to form a

Adhesion of the adjacent semiconductor devices 10a, 10b, 10c, lOd to the contact layers 1, 2 to prevent. Because such spacers are not present in the stack, the stack of semiconductor devices 10a, 10b, 10c, 10d may be substantially more for the same size of stack

Semiconductor devices include as a stack with

Spacers. Thus, with the same effort more Semiconductor devices are provided simultaneously with coatings 7, 8. In particular, in this way

reflection-reducing or reflection-increasing coatings 7, 8 simultaneously on a plurality of laser bars

be applied.

The invention is not limited by the description with reference to the embodiments. Rather, the includes

Invention every new feature as well as every combination of

Features, which includes in particular any combination of features in the claims, even if this feature or this combination itself is not explicitly in the

Claims or embodiments is given.

Claims

Semiconductor device (10).

- a semiconductor body (3) which has a first main surface (11) and one of the first main surfaces (11)

has opposite second main surface (12),

- a first contact layer (1) on the first

Main surface (11) and a second contact layer

(2) on the second main surface (12),

where

- The semiconductor body (3) has a recess (4) on the first main surface (11), which is formed by two opposite side surfaces (5, 6) of the

semiconductor body

(3) each has a distance,

- the first contact layer (1) completely in the

Depression (4) is arranged, and

the second contact layer (2) from each other

opposite side surfaces (5, 6) have an equal or greater distance than the recess (4).

Semiconductor device according to claim 1,

where a vertical projection of the second

Contact layer (2) on the first main surface (11) of the semiconductor body lies completely within the recess (4).

Semiconductor device according to one of the preceding claims,

wherein the depression (4) has a depth that is greater than the sum of a thickness of the first contact layer (1) and a thickness of the second contact layer (2).

4. Semiconductor device according to one of the preceding claims,

wherein a front side (15) and/or a back side (16) of the semiconductor device has a coating (7, 8).

5. Semiconductor device according to claim 4,

wherein the coating (7, 8) is a reflection-increasing or a reflection-reducing coating.

6. Semiconductor device according to one of the preceding

Expectations,

wherein the semiconductor device (10).

is an optoelectronic component.

7. Semiconductor device according to one of claims 4 or 5, wherein the semiconductor device (10) is a semiconductor laser and the front side (15) and the back side (16)

Form the resonator mirror of the semiconductor laser.

8. Semiconductor device according to one of the preceding

Expectations,

wherein the semiconductor body (3) has a semiconductor layer sequence (32) applied to a substrate (31).

and wherein the recess (4) is formed in the substrate (31).

9. Semiconductor device according to one of the preceding

Expectations,

wherein the depression (4) is at a distance of at least 50 μm from the side surfaces (5, 6).

10. A method for applying a coating (7, 8) to a plurality of semiconductor devices (10a, 10b, 10c, 10d)) according to one of the preceding claims, with

Steps:

- Stacking the semiconductor devices (10a, 10b, 10c, 10d) in such a way that the first main surface (11) of a semiconductor device (10a) and the second

Main surface (12) of an adjacent one

Semiconductor device (10b) face each other, the recess (4) in the semiconductor body (3).

Semiconductor device (10) and the second main surface (12) of the adjacent semiconductor device (10), the first contact layer (1) of the semiconductor device (10) and the second contact layer (2) of the adjacent

Enclose semiconductor device (10), and

- Applying a coating (7, 8) to one

Front (15) and/or a back (16) of the

stacked semiconductor devices (10a, 10b, 10c, lOd).

11. Method according to claim 10,

12. Method according to one of claims 10 or 11,

wherein the semiconductor device (10).

is an optoelectronic component.

13. Method according to one of claims 10 to 12,

wherein the semiconductor device (10) is a semiconductor laser and the front side (15) and the back side (16) form resonator mirrors of the semiconductor laser.