JPH06291364A - Semiconductor light emitting device and its manufacturing method - Google Patents

Abstract

PURPOSE:To provide a highly integrated light emitting diode array maintaining the thickness of each light emitting element. CONSTITUTION:On an n-type substrate 1, an n-type buffer layer 2, an n-type clad layer 3, a p-type active layer 4, a p-type lower clad layer 5 and an n-type current constricting layer 6 are formed in sequential order, and on this n-type current constricting layer 6, grooves are formed in the direction of the array. A p-type upper clad layer 7 is formed on it, and a p-type contact layer 8 and electrodes 9 are formed. Each light emitting element is isolated in the array direction and vertical directions by etching grooves formed in the p-type upper clad layer 7 and each light emitting element is electrically isolated by these grooves and the n-type current constricting layer 6. The p-type active layer 4, located under the n-type current constricting layer 6, consists a light emitting part 4a and as the electrode 9 is formed avoiding the upper part of this light emitting part 4a, it does not interrupt the emitted light and the efficiency of the light emission is high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device such as a surface emitting monolithic light emitting diode array and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a light emitting diode array has been used in various information devices such as a display device and an LED printer device as a light source. In a monolithic light-emitting diode array in which a plurality of light-emitting portions (light-emitting elements) are formed in rows on the surface of a compound semiconductor made of each layer epitaxially grown on a single crystal substrate, each light-emitting element has a selective diffusion method or a mesa type Each is separated by an etching method or the like.

Then, for example, GaA is formed on a GaAs substrate.
When the light emitting portion of the compound semiconductor in which the sP layer is epitaxially grown is separated by the selective diffusion method, Zn (zinc) is diffused into the boundary portion of each light emitting element in the epitaxially grown GaAsP layer. It is often used as a suitable method for manufacturing.
Further, in a light emitting diode array having an AlGaAs double heterojunction, which can be expected to have high brightness, the light emitting portion is separated by mesa etching by photolithography.

[0004]

In recent years, there has been a demand for higher density of the light emitting diode array, and for that purpose, the distance between the light emitting elements must be 20 μm or less. However, in order to separate the respective light emitting elements within this distance by the selective diffusion method, the diffusion depth must be controlled to about 10 μm or less. It was difficult to do.

Further, when a light emitting diode array having a double hetero structure is manufactured, AlGaAs is generally grown by a liquid phase epitaxy (LPE) method. However, when fine processing is performed by etching, a film is formed. Since the thickness needs to be several μm or less, it is difficult to control the film thickness to be thin by the liquid phase growth method, and the reproducibility is poor. And MOC
In the case of stacking by the VD method or the MBE method, since fine control is possible, it is possible to reduce the film thickness to enable fine processing, but when the film thickness is reduced, the light emission output of each light emitting element decreases. However, there is a problem that high brightness cannot be obtained. Therefore, it is an object of the present invention to provide a light emitting diode array in which the film thickness of each light emitting element is increased and the density is increased, and a manufacturing method thereof.

[0006]

As means for achieving the above object, in a semiconductor light emitting device having a plurality of light emitting elements formed in a row in a compound semiconductor having a pn junction, each of the light emitting elements is A semiconductor light emitting device characterized by being electrically separated by a current confinement layer provided in a direction parallel to the columnar direction and an etching groove provided up to the current confinement layer in a direction perpendicular to the columnar direction. ,
A method for manufacturing a semiconductor light emitting device, in which a plurality of light emitting elements are formed in rows on a surface of a compound semiconductor having a pn junction, the method comprising: a buffer layer, a clad layer, an active layer, a lower clad layer, and a current constriction layer on a substrate. Sequentially laminating the current confinement layer with grooves parallel to the columnar direction, laminating an upper clad layer on the current confinement layer to provide an electrode, and the upper clad layer And a step of selectively etching the current confinement layer in the direction perpendicular to the column shape to separate the light emitting elements into the respective light emitting elements. is there.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A perspective view of a light emitting diode array which is an embodiment of a semiconductor light emitting device of the present invention is shown in FIG. 1 and will be described below. The light emitting diode array shown in the figure is an n-type GaA.
n-type GaAs buffer layer 2, n-type AlGa on s substrate 1
As clad layer 3, p-type GaAs (or AlGaA
s) Active layer 4, p-type AlGaAs lower cladding layer 5, n
Type GaAs current confinement layers 6 are sequentially stacked.
The type GaAs current confinement layer 6 has grooves formed in the array direction. Then, the p-type AlGaAs upper cladding layer 7 is laminated thereon, and the p-type GaAs contact layer 8 and the electrode 9 are provided so as to avoid the upper portion of the groove of the n-type GaAs current constriction layer 6. In addition, each light emitting element portion is a p-type AlG
By the groove in which the aAs upper clad layer 7 is etched,
It is divided.

In the light emitting diode array having such a structure, the p-type GaA under the groove of the n-type GaAs current confinement layer 6 is formed.
The s active layer 4 becomes the light emitting portion 4a, and the p-type A
It is output from the surface of the 1GaAs upper clad layer 7 to the outside. At this time, since each light emitting element is electrically separated by the groove provided in the p-type AlGaAs upper clad layer 7 in the direction perpendicular to the array direction and the n-type GaAs current confinement layer 6, each light emitting element is independent. Can be operated. Further, since the electrode 9 is provided so as to avoid the upper portion of the groove of the n-type GaAs current confinement layer 6 (the upper portion of the light emitting portion 4a) which becomes the light emitting surface, it does not block the emitted light and the light emitting efficiency is improved. Get higher

Next, a method of manufacturing this light emitting diode array will be described with reference to FIGS. As shown in FIG. 2A, an n-type GaAs buffer layer 2, an n-type AlGaAs cladding layer 3, and a p-type GaA are formed on an n-type GaAs substrate 1.
The s active layer 4, the p-type AlGaAs lower cladding layer 5, and the n-type GaAs current confinement layer 6 are sequentially laminated by the MOCVD method.

Then, as shown in FIG. 1B, an etching mask is provided by a photolithography process, and etching is performed using an ammonia / hydrogen peroxide water-based etching solution to form an array on the n-type GaAs current confinement layer 6. Forming a groove in the direction. At this time, the etching solution is p-type Al.
Since the GaAs lower cladding layer 5 is hardly etched, accurate selective etching is possible. Further, as shown in FIG. 3C, p-type Al is formed by MOCVD.
The GaAs upper clad layer 7 and the p-type GaAs contact layer 8 are laminated.

After that, as shown in FIG.
N is formed as a light emitting surface of each light emitting element by vapor deposition of a metal to be formed and a photolithography process followed by etching or a lift-off method.
Electrode (and bonding pad) at a predetermined position avoiding the upper part of the groove provided in the type GaAs current confinement layer 6
9 is provided. Then, p-type GaAs other than the lower part of the electrode 9
The contact layer 8 is removed by selective etching using an ammonia / hydrogen peroxide water-based etching solution.

Finally, an etching mask is provided by a photolithography process, and the p-type AlGaAs upper clad layer 7 is etched in a direction perpendicular to the array direction using a hydrochloric acid-based etching solution, as shown in FIG. Separate each light emitting element. It should be noted that FIG. 6E is a view seen from the X direction in FIG. At this time, n-type GaAs
By using the current confinement layer 6 as an etching stopper layer, accurate etching is possible.
Then, if necessary, a surface non-reflective layer such as SiN may be formed and the bonding portion may be perforated.

[0013]

According to the semiconductor light emitting device of the present invention, each light emitting element is formed by a current confinement layer provided in a direction parallel to the column direction and an etching groove provided up to the current confinement layer in a direction perpendicular to the column direction. Since they are electrically separated, it is possible to easily control the etching depth during manufacturing, and it is possible to accurately separate the light emitting elements even if the density of the light emitting elements is increased.

Further, in the method for manufacturing the semiconductor light emitting device of the present invention, since the current confinement layer is used as the etching stopper layer, accurate etching separation can be performed without thinning the upper cladding layer, and the luminous efficiency can be improved. Can be increased.

Further, by forming the electrode while avoiding the upper portion of the groove formed in the current confinement layer serving as the light emitting surface, the emitted light is not blocked by the electrode, and the light emitting efficiency can be further improved. The effect is that you can do it.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a semiconductor light emitting device of the present invention.

2A to 2D are process diagrams for explaining a method for manufacturing a semiconductor light emitting device of the present invention.

[Explanation of symbols]

 1 n-type GaAs substrate 2 n-type GaAs buffer layer 3 n-type AlGaAs clad layer 4 p-type GaAs (or AlGaAs) active layer 4a light emitting part 5 p-type AlGaAs lower clad layer 6 n-type GaAs current confinement layer 7 p-type AlGaAs upper clad Layer 8 p-type GaAs contact layer 9 Electrode

Claims (3)

[Claims] 1. A semiconductor light emitting device having a plurality of light emitting elements formed in a row in a compound semiconductor having a pn junction, wherein each of the light emitting elements includes a current confinement layer provided in a direction parallel to the row direction. A semiconductor light emitting device, wherein the semiconductor light emitting device is electrically isolated by an etching groove provided up to the current confinement layer in a direction perpendicular to the columnar direction. 2. A method for manufacturing a semiconductor light-emitting device, which comprises forming a plurality of light-emitting elements in rows on the surface of a compound semiconductor having a pn junction, comprising a buffer layer, a clad layer, an active layer, a lower clad layer, and a substrate. A step of sequentially laminating current confinement layers, a step of forming grooves in the current confinement layers in a direction parallel to the columnar direction, a step of laminating an upper clad layer on the current confinement layers and providing electrodes, A method of manufacturing a semiconductor light emitting device, comprising the step of selectively etching the upper clad layer in the direction perpendicular to the columns by using the current confinement layer to separate the light emitting elements. 3. The semiconductor light emitting device according to claim 1, wherein the electrode is formed so as to avoid an upper portion of a groove formed in the current confinement layer which becomes a light emitting surface.