JPH01155669A - Array-type semiconductor light-emitting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor light-emitting device, and more particularly to an array-type semiconductor light-emitting device in which semiconductor light-emitting devices are formed in an array, and light emitted within the device can be extracted perpendicularly to a substrate. .

Japanese Patent Application No. 1981-2007 was proposed as a device to compensate for the drawbacks of conventional surface-emitting semiconductor lasers, such as CTJ-type light-emitting devices and Burrus-type surface-emitting devices, which emit emitted light perpendicularly to the substrate.
Devices such as No. 002891 or Japanese Patent Application No. 1983-48F183 have been proposed. Patent application 1982-0028
In the device No. 91, an n-type semiconductor layer is laminated on an n-type semiconductor substrate, an n-type semiconductor light-emitting layer is laminated on the n-type semiconductor layer, and a p-type semiconductor layer is laminated on the light-emitting layer. , an n-type semiconductor layer is stacked on the p-type semiconductor layer, and the n-type semiconductor layer has a substantially recessed portion formed in the direction perpendicular to the substrate on the main surface side of the substrate, that is, on the stacked side of each layer. * A P-n junction is formed approximately around the recess, and by passing a current between the electrodes formed on the stack side and the substrate surface, light emission occurs in the active region and the optical output is directed approximately perpendicular to the substrate. It was possible to take it out in any direction. In this structure, a pnpn current blocking structure is formed by the p-type diffusion region formed around the recess and the laminated structure described above, and when a current is passed between the electrodes of the device, the injected current emits light. It was possible to efficiently inject into the light emitting region of the layer.

When forming an array of these elements and operating each element individually, this has been done by devising an electrode pattern to form electrodes corresponding to individual light emitting parts. However, by simply isolating the light emitting portions using the electrode pattern, it is difficult to achieve electrode separation between adjacent elements when the spacing between the elements becomes narrow. therefore.

Even when a current is applied to only the electrodes corresponding to the device in order to operate a desired element, the current flows into the light emitting region of the adjacent element, causing the adjacent element to operate at the same time as the desired element. was occurring.

In order to solve this problem, there has been a method in which an insulating layer is embedded between the light emitting parts of each element. but,
In this case, in order to embed the insulating layer, a hole is made in the element.
There is a drawback that the process of embedding an insulating layer is required after that, which complicates the manufacturing process of an array type semiconductor light emitting device in which elements are formed in an array.

Purpose The present invention solves the drawbacks of the prior art and improves electrical isolation between adjacent elements, thereby providing an array type semiconductor light emitting device that enables individual operation of elements in a small, high-density array between adjacent elements. The purpose is to provide equipment.

In order to achieve the above object, the present invention includes a semiconductor substrate,
formed on the main surface of a semiconductor substrate, having a p-n junction,
In an array-type semiconductor light-emitting device including a plurality of semiconductor light-emitting elements having a light-emitting layer that emits light in a direction substantially perpendicular to the main surface near the p-n junction and an electrode that injects current into the light-emitting layer, The plurality of semiconductor light emitting devices have a recess formed in a laminated portion on the substrate in a direction substantially perpendicular to the main surface, a p-n junction is mainly formed along the side surface of the recess, and a plurality of semiconductor light emitting devices are provided. This device is characterized in that a gap is formed between the semiconductor light emitting devices to electrically isolate each device. Hereinafter, the present invention will be specifically explained based on examples.

In the present invention, a current blocking layer is laminated on a first conductive type semiconductor substrate, and a second conductive type semiconductor layer is laminated on the current blocking layer. Further, in the semiconductor layer of the second conductivity type, a plurality of substantially concave portions are formed in a direction perpendicular to the substrate on the main surface side of the substrate, that is, on the stacked side of each layer, and the lower part of the step of each substantially concave portion is the first concave portion. It is formed to reach a conductive type semiconductor substrate.

By thermally diffusing impurities that form the first conductivity type, an active region of the first conductivity type is formed substantially on the side surface of the recess, or on the substantially side surfaces of the recess and the bottom surface of the recess, and a p-n junction is formed approximately around the recess. It is formed.

Each of the plurality of substantially concave portions is formed as a light emitting portion that emits light perpendicularly to the substrate, and the light emitting portions are arranged in an array.

In addition, a gap is formed in the second conductivity type semiconductor layer having a light emitting region to isolate each light emitting part. It is formed with a predetermined depth.

The electrodes on the second conductivity type side are individually formed so as to correspond to the respective light emitting portions formed on both sides of the gap on the surface of the second conductivity type semiconductor layer, that is, in each substantially concave portion. Also, the first
The electrode on the conductive type side is formed as a common electrode for each light emitting section on the back surface of the substrate, that is, on the substrate surface on the opposite side to the lamination side of each layer.

With the above structure, when a current is passed between the electrodes on the first conductivity type side and the electrodes on the second conductivity type side, the plurality of light emitting parts formed in the device are connected to adjacent light emitting parts. Since there is no mutual electrical interference, each light emitting section can be operated independently. Therefore, light output can be extracted from a desired light emitting section formed in the device.

FIG. 1 shows a sectional view of an embodiment of an array type semiconductor light emitting device according to the present invention. This device was developed by patent application in 1982.
The present invention is applied to the case where the semiconductor light emitting devices according to No. 48883 are arrayed.

A high-resistance current blocking layer R130 made of i-type GaAs or the like is laminated on a p-type gallium arsenide (GaAs) substrate 101, and a semiconductor light-emitting layer made of n-type GaAg or AlGaAs is laminated on the current blocking layer 130. 102 are stacked. In addition, the n-type light emitting layer 102 has a substantially cylindrical substantially recessed portion 140 (including substantially recessed portions 140a and 140b) in a direction perpendicular to the substrate 101 on the main surface side of the substrate 101, that is, on the laminated side of each layer. ) is formed, and the lower part of the step of the substantially recessed part 140 is formed so as to reach the substrate 101.

Further, by diffusing an impurity such as zinc (Zn) into the inner side surface of the substantially recessed portion 140, the p-type diffusion region 131 (p
A p-type diffusion region including p-type diffusion regions 131a and 131b) is formed. This P type diffusion region 13
1 is formed substantially along the side surface of the recess 140, and its lower part reaches the substrate 101. By forming the p-type diffusion region 131, a p-n junction 108 (general term for p-n junctions including p-n junctions 108a and 108b) is formed.
A plurality of substantially concave portions 140 having zero or more structures are formed substantially perpendicularly to the substrate 101 in an array shape, and a light emitting portion 200 (light emitting portion) that emits light perpendicularly to the substrate 101 is formed on the substrate 101. 200a and 200b are collectively referred to as a light emitting section).

Further, in the n-type light-emitting layer 102 having the light-emitting region 131, a gap 161 is formed to isolate each light-emitting part 200. A zero gap 181 is formed on the top of the n-type light-emitting layer 102, and the substrate 10
The current blocking layer 13 is formed toward the substrate 101 in a direction substantially perpendicular to the current blocking layer 13 in the n-type light emitting layer 102 .
It is formed to a depth that does not reach zero.

The n-side electrodes 107 (collectively the n-side electrodes including the n-side electrodes 107a and 107b) are individually formed on the upper part of the n-type light emitting layer 102 so as to correspond to each substantially concave portion 140, that is, each light emitting section 200. The P-side electrode 10B is formed as a common electrode for each light emitting section on the back surface of the substrate 101, that is, on the surface of the substrate opposite to the lamination side of each layer.

P-side electrode 10B of common electrode and n-side electrode 107 of individual electrode
By passing current through both type electrodes, the current is injected into the p-n junction 108 formed almost perpendicular to the substrate 101, and light emission occurs due to carrier recombination. an opening 150 on the side, i.e. on the top of the device;
The light output can be extracted vertically upward from the substrate 101 as a light output.

For example, when a current is passed between the p-side electrode 108 of the common electrode and the n-side electrode 107a of the individual electrodes, the current is injected into the p-n junction 108a formed approximately around the recess 140a, Light is emitted at the -n junction 108a, and the emitted light can be extracted from the opening 150a vertically upward relative to the substrate 101 as optical output. Furthermore, when a current is passed between the p-side electrode 108b and the n-side electrode 107b of the common electrode, the current is injected into the p-n junction 108b formed approximately around the concave portion 140b, and the p-n
Light is emitted at the junction 108b, and the emitted light can be extracted from the opening 150b vertically upward relative to the substrate 101 as optical output. In this way, in this example,
Since the gap 1131 is formed between each of the light emitting parts 200, mutual electrical interference between the adjacent light emitting parts 200a and 200b can be significantly suppressed. Therefore, it is possible to operate each light emitting section independently and extract light output from a desired light emitting section.

Note that the gap 181 may be formed in a stripe pattern between adjacent light emitting units 200, as in the device shown in FIG. In addition, when forming a two-dimensional array, the gaps 181 are formed in a pattern that surrounds each light emitting part 200, as in the apparatus shown in FIG. 5, which will be described later. The gaps 161 can be formed in an appropriate pattern depending on the arrangement pattern.

It goes without saying that the gap 161 can be formed at the same time as the p-type diffusion region 131 is formed, and can also be formed at a time other than when the p-type diffusion region 131 is formed.

FIG. 2 shows a cross-sectional view of an example in which the gap 161 formed in the device shown in FIG. 1 is formed to penetrate the current blocking layer 130 and reach the substrate 101.

In the structure of this device, the light emitting layer 1 in each light emitting section 200
02 are completely separated by the gap 161, when a current is passed through both the p-side electrode 108 of the common electrode and the n-side electrode 107 of the individual electrode, the electricity between the adjacent light emitting parts 200 complete separation is achieved, and no current is injected into the adjacent light emitting section 200. Therefore, the efficiency of current injection into each light emitting section 200 is further improved.

Note that the depth of the gap 161 is formed to a depth that does not reach the substrate 101 in the current blocking layer 130 in the device shown in the embodiment of FIG. 1 or in addition to the device shown in this embodiment. You can also do it.

FIG. 3 shows a sectional view of another example of the array type semiconductor light emitting device according to the present invention. This device was developed by patent application in 1981.
The present invention is applied to the case where semiconductor light emitting devices according to No. 002891 are arrayed.

An intermediate layer 210 made of n-type AlGaAs is laminated on an n-type gallium φ arsenide (GaAs) substrate 201, and a semiconductor light emitting layer 202 made of n-type GaAs or AlGaAs is laminated on the intermediate layer 210. A current blocking layer 230 is laminated on the semiconductor light emitting layer 202, and n-type GaAs or AlG is formed on the current blocking layer 230.
A layer 203 made of aAg is laminated. Further, in the n-type layer 203, a substantially cylindrical substantially recessed portion 140 is formed in a direction perpendicular to the substrate 101 on the main surface side of the substrate 101, that is, on the laminated side of each layer, and the lower part of the step of the substantially recessed portion 140 is formed. It is formed to reach the intermediate layer 210.

In addition, a p-type diffusion region 131 is formed by diffusing an impurity such as zinc (Zn) into the substantially inner side surface of the recess 140 . This p-type diffusion region 131 is formed on the surface of the laminated portion,
and is formed substantially along the side surfaces of the recessed portion 140, and the lower portion thereof reaches the intermediate layer 210. By forming the p-type diffusion region 131, the p-n junction 108 is connected to the substrate 10.
A plurality of substantially concave portions 140 having zero or more structures formed substantially perpendicular to the substrate 101 are formed in an array on the substrate 101, and constitute a light emitting portion 200 that emits light in a direction perpendicular to the substrate 101. ing.

Further, a gap 181 is formed in the n-type layer 203 to isolate each light emitting part 200.
03, in a direction substantially perpendicular to the substrate 101,
It is formed toward the substrate 101 and has a depth equal to that of the current blocking layer 2.
It is formed to a depth of up to 30 mm.

The p-side electrode 106 is formed in each substantially concave portion 1 on the top of the n-type layer 203.
04, that is, they are formed individually to correspond to each light emitting section 200, and the n-side electrode 107 is formed as a common electrode for each light emitting section on the back surface of the substrate 101, that is, on the substrate surface on the opposite side to the lamination side of each layer. has been done.

N-side electrode 107 of the common electrode and p-side electrode 106 of the individual electrode
By passing a current through both electrodes, a current is injected into the p-n junction 10B formed almost perpendicular to the substrate 101, and light is emitted due to carrier recombination.The emitted light is directed to the p-side electrode 106 side. , i.e. the opening 150 at the top of the device.
The light output can be extracted vertically upward from the substrate 101 as a light output.

Note that the gap 161 can be formed by dry etching using a C12 gas system. Also, sulfuric acid,
The gap 161 can also be formed by wet etching using a solution of hydrogen peroxide and water, and in this case, the cross-sectional shape of the gap 161 is a mesa type or an inverted mesa type.

FIG. 4 shows a perspective view of an example in which the array type semiconductor light emitting device according to the present invention is formed into a one-dimensional array.

In this example, the upper part of the element, that is, the opening 15 formed in the element.
When viewed from zero, a p-type diffusion region 131 is formed around the opening 150 at the top of the element forming each light emitting section 200, and the p-type diffusion region 131 is
The zero gap 161 in which the n-side electrode 107 of the individual electrode is formed around the type diffusion region 131 is, for example, the light emitting part 200C.
and a light emitting part 200d adjacent to the light emitting part 200C in a stripe shape, and the blue light emitting part is electrically separated by this gap 181. Therefore, the light emitting section 200C and the light emitting section 200d can be operated independently.

FIG. 5 shows a cross-sectional perspective view of a case where the light emitting parts having the structure shown in FIG. 2 are formed in a two-dimensional array.

In this example, as shown in the figure, one gap 181 is formed so as to surround each of the light emitting sections 200 formed in a two-dimensional array. Therefore, by passing current through the circular electrodes of the p-side electrode 10EI of the common electrode and the n-side electrode 107 of the individual electrodes, each light emitting section 200 can be operated individually, and the opening corresponding to the desired light emitting section 200 can be opened. Light output can be extracted from 150.

In this example, each of the light emitting parts 200 formed in a two-dimensional array is surrounded by a rectangular gap 181, but the formation pattern of the gap 181 is different from that of each light emitting part 2.
Depending on the shape of the extraction electrode 00, it can be formed into various shapes, such as a circle or a polygon.

In each embodiment of the present invention shown above, the light emitting section 200
N-side electrode 107 of the individual electrodes excluding the nearby current injection region
It is also possible to form an electrically insulating layer between the semiconductor layer and the semiconductor layer formed in contact with the individual electrode. By forming this electrically insulating layer, the efficiency of current injection into the p-type diffusion region 131 can be further improved.

The present invention not only provides an array type semiconductor light emitting device having the structure of the above embodiment, but also provides a reflective mirror or a reflective layer of a semiconductor laminated structure above or below the light emitting region 131 of the light emitting section 200, or above and below the light emitting region 131. It is also possible to apply the present invention to semiconductor light emitting devices and semiconductor lasers having a structure. In addition, the previously proposed patent application No. 81-002891
No., or elements such as patent application No. 82-4ft 883, etc.
The laminated portion formed on the upper part of the substrate has a recess formed perpendicular to the substrate, and a p-n junction perpendicular to the substrate is formed around the recess, and a p-n junction on the surface of the element is formed. It can also be applied to an array of elements that extract light in a direction perpendicular to the substrate, in which an n-type layer is formed around the surface and exposed on the surface.

In each embodiment, the current blocking layers 130 and 230 may have a structure in which two or three p-type semiconductor layers and n-type semiconductor layers are alternately stacked.

The light emitting layer 102 is made of GaAsP, InGaAsP, I
nGaP, InGaAIP.

Zn5e, ZnS, etc. can be used.

Further, although the cross section of the recess in each of the above embodiments is formed into a substantially circular shape, the cross section is not limited to a circle, but may be formed into a rectangular shape, a polygonal shape, or the like.

For reference, an example of what has been conventionally proposed as a surface emitting semiconductor device is shown in FIG.

An intermediate layer 2 made of an n-type semiconductor is laminated on an n-type semiconductor substrate 1, an n-type semiconductor light emitting layer 3 is laminated on the intermediate layer 2, and a p-type semiconductor layer 4 is laminated on the light emitting layer 3. An n-type semiconductor layer 5 is laminated on the p-type semiconductor layer 4, and the n-type semiconductor layer 5 has a layer approximately perpendicular to the substrate 1 on the main surface side of the substrate 1, that is, on the lamination side of each layer. A recess 14 is formed. A p-n junction 18 is formed approximately around the recess 14, and by passing a current between the electrodes 6 and 7 formed on the lamination side and the substrate surface, light emission occurs in the active region and light output is generated. It can be taken out in a direction substantially perpendicular to the substrate 1. In this structure, a p-type diffusion region is formed around the four parts, and a pnpn current blocking region is formed by this p-type diffusion region and the above-mentioned laminated structure, so that current is not allowed to flow between the electrodes of the element. In this case, the injected current could be efficiently injected into the light emitting region of the light emitting layer. In addition, when these elements are arranged in an array and each element is operated individually, the pattern of the electrodes is devised to form electrodes corresponding to the individual light emitting parts 20. However, by simply isolating the light emitting portions using the electrode pattern, it is difficult to achieve electrode separation between adjacent elements when the spacing between the elements becomes narrow. Therefore, even if current is applied to only the electrode corresponding to a desired element in order to operate that element, the current will flow into the light emitting region of the adjacent element, causing the adjacent element to operate at the same time as the desired element. A problem had arisen.

However, in the device according to the present invention shown in FIGS. 1 to 5, each light emitting section 200 formed in an array type semiconductor light emitting device is
A gap 181 is formed between adjacent light emitting parts 20.
Since mutual electrical interference between the two light emitting parts can be significantly suppressed, each light emitting part can be operated independently. Therefore, by passing a current through the electrode corresponding to the light emitting part, it is possible to extract light output from the desired light emitting part.

Moreover, a recess 140 is formed in the element in a direction substantially perpendicular to the main surface of the semiconductor substrate 101, and a p-n junction 108 forming an active region absorbs light output from the sides of the recess 140. Because it is long in the direction of extraction,
High luminous efficiency can be obtained. Furthermore, since the active region is formed on the side surface of the recess, heat dissipation characteristics are improved. Therefore 2
The substrate 1 uses the light generated in the light emitting region as a high light emitting output.
It can be taken out in a direction perpendicular to 01.

Furthermore, in device manufacturing, the device of the present invention can electrically isolate each light emitting part by forming a gap between adjacent elements, so there is no need to perform complicated steps such as embedding an insulating layer. do not have.

Advantage-1 According to the present invention, a gap is formed between each light emitting part formed in an array type semiconductor light emitting device to electrically isolate each light emitting part. It is possible to significantly suppress mutual interference. Therefore, it is possible to operate each light emitting part of a small high-density array between adjacent elements independently, and light output can be extracted from a desired light emitting part by passing current through the electrode corresponding to the light emitting part. . Moreover, since the active region of the light emitting part is formed on the side surface of the recess, heat dissipation efficiency is improved, and a decrease in luminous efficiency due to a rise in the temperature of the active region can be prevented. Large luminous output can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view partially showing one embodiment of an array type semiconductor light emitting device according to the present invention, and FIGS. 2 and 3 are partially sectional views showing other examples of the array type semiconductor light emitting device according to the present invention. 4 is a perspective view partially showing an embodiment in which the present invention is applied to a one-dimensional array type semiconductor light-emitting device. FIG. FIG. 6 is a perspective view showing an example in which semiconductor light emitting devices according to the prior art are arranged in an array. Part No. 1 101.201 , , , , Substrate 102.202
, , , , light emitting layer 10B , , , , , ,
, p-side electrode 107 , , , , , n-side electrode 130.230 , , , current blocking layer 131
, , , , , , P-type diffusion region 140 ,
, , , , , recess 150 , , , , , , opening 181 ,
, , , , , gap 200 , , , , ,
, Light emitting part Fig. 1 Fig. 2 Fig. 3

Claims (1)

[Claims] 1. A semiconductor substrate; formed on the main surface of the semiconductor substrate, having a p-n junction;
An array type semiconductor light emitting device including a plurality of semiconductor light emitting elements having a light emitting layer that emits light in a direction substantially perpendicular to the main surface in the vicinity of the p-n junction, and an electrode that injects current into the light emitting layer. In the device, the plurality of semiconductor light emitting elements have a recess formed in a laminated portion on the substrate in a direction substantially perpendicular to the main surface, and the p-n junction mainly forms a side surface of the recess. What is claimed is: 1. An array type semiconductor light emitting device, characterized in that a gap is formed between the plurality of semiconductor light emitting elements to electrically isolate each element.