JPH06120618A - Semiconductor light emitting element - Google Patents

Abstract

PURPOSE:To manufacture a semiconductor light emitting element by the first crystal growth by putting it in current constriction structure without recrystallized interface. CONSTITUTION:A projection 21 triangular in cross section is formed over the overall length on the center of one face of an n-GaAs substrate 20 by etching. A p-GaAs current block layer 22 is grown, as far as the vicinity of the top of the projection 21, at the face where the projection 21 is formed, and further subsequently the first clad layer 23 of n-GaAlAs, the light emitting layer 24 of GaAs, the second clad layer 25 of GaAlAs, and the contact layer 26 of p<+>- GaAs are grown in order. An electrode 27, on the contact layer 26, and an electrode 28, on the bottom of the substrate 20, are formed. The flow of a current is narrowed at the top of the projection 21 by the block layer 22, and a light is confined in by the curvature of a light emitting layer 24 based on the projection 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractive index guided semiconductor light emitting device having a current narrowing structure.

[0002]

2. Description of the Related Art A conventional semiconductor light emitting device of this type is shown in FIG. n-type GaAl on the flat surface of n-type GaAs 10
A first clad layer 11 of As is formed by crystal growth, and a light emitting layer 12 of GaAs is crystal-grown on the first clad layer 11.
-Shaped GaAlAs thin second cladding layer portion 13 is formed, followed by n-type GaAs current blocking layer 14.
Is formed. Next, the central portion of the current blocking layer 14 is removed by etching to form the slit 15 over the entire length. After that, p is formed on the current blocking layer 14 and in the groove 15.
The other end 16 of the second cladding layer of GaAlAs is crystal-grown and connected to the part 13 of the second cladding layer through the slit 15. A p ⁺ GaAs contact layer 17 is crystal-grown on the second cladding layer 16. An electrode 18 is formed on the first cladding layer 11 of the substrate 10.
An electrode 19 is formed on the surface opposite to the surface.

When a current is passed between the electrodes 18 and 19, the current is narrowed by the current blocking layer 14 in the slit 15 and flows only near the center of the light emitting layer 12, and light emission occurs in this portion. By making the second clad layer 13 have a very thin structure, the light excited in the light emitting layer 12 can emit light.
It is confined in the central portion corresponding to the slit 15 and becomes a refractive index waveguide type light emitting element.

[0004]

In the conventional refractive index waveguide type semiconductor light emitting device, the slit 15 is formed by etching in order to narrow the current.
Crystal growth is divided into two steps: a step of sequentially growing the clad layer 11, the light emitting layer 12, the second clad layer 13, and the current blocking layer 14 and a step of sequentially growing the second clad layer 16 and the contact layer 17. I had to do it.

During the etching process for forming the slits 15, the interface portion at the time of re-growth is exposed to the air, so that the surface is oxidized or impurities are attached to the second cladding layer. A peculiar interface is formed with respect to the crystal growth of 16, which may adversely affect the produced semiconductor light emitting device. In particular, when the second clad layer 13 was exposed to air on the surface before regrowth, it was very difficult to protect the surface so as not to have an adverse effect such as oxidation and form a good regrowth interface.

An object of the present invention is to make it possible to manufacture by a single continuous crystal growth, and therefore, a refractive index guided semiconductor having a current constriction structure which operates well without having a peculiar recrystallizing interface on the way. It is to provide a light emitting element.

[0007]

According to the present invention, a ridge having a triangular cross section is formed over the entire length in the center of one surface of a semiconductor substrate of one conductivity type, and the tops of the ridges are slightly left on both sides of the ridge. A current block for interrupting a current is formed on the one surface of the semiconductor substrate, and a first clad layer having the same conductivity type as the semiconductor substrate is formed so as to cover both current blocks and the tops of the ridges. A light emitting layer is formed thereon, a second conductivity type second clad layer is formed on the light emitting layer, and a high-concentration reverse conductivity type contact layer is formed on the second clad layer.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, which will be described by explaining its manufacturing method. A ridge (a regular mesa convex structure) 21 having an isosceles triangular cross section 21 is formed over the entire length in the center of one surface of the n-type GaAs substrate 20 by etching. On the n-GaAs substrate 20 on which the protrusion 21 is formed, a p-GaAs current block layer 22 is grown to near the top of the protrusion 21 by a crystal growth device such as MOCVD.
Continuing further, the first cladding layer 2 of n-GaAlAs
3, a light emitting layer 24 of GaAs, a second cladding layer 25 of p-GaAlAs, and a contact layer 26 of p ⁺ -GaAs are sequentially grown. After that, an electrode 27 is formed on the contact layer 26, and an electrode 28 is formed on the bottom surface of the n-GaAs substrate 20.

When a current is made to flow between the electrodes 27 and 28, the passage of the current is limited by the p-GaAs current blocking layer 22 only to the vicinity of the top of the ridge 21 and the light emitting layer 24.
The current is narrowed to the center of the. Further, the GaAs light emitting layer 24 has a convex structure of the substrate 20, that is, the ridge 2
Due to the effect of 1, the area near the center is bent into a peak. The light is confined by the bending of the light emitting layers 24 on the left and right near the top, and the light has a refractive index guiding structure.
Light is emitted near the top of 4 and is confined in this part.

As described above, according to the structure of the present invention, the index-guided semiconductor light emitting device having the current narrowing structure can be grown once during the manufacturing process without exposing to air. The basic structure can be manufactured, and a high quality light emitting device having no regrowth interface can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view showing a conventional semiconductor light emitting device.

Claims (1)

[Claims] 1. A one-conductivity-type semiconductor substrate having a ridge having a triangular cross section on one surface, and a current block formed on the one surface of the semiconductor substrate, leaving a little top portion on both sides of the ridge, for interrupting a current. Layer, a first clad layer of the same conductivity type as the semiconductor substrate formed over both current blocking layers and the tops of the protrusions protruding therefrom, and a light emitting layer formed on the first clad layer And a second clad layer formed on the light emitting layer and having a conductivity type opposite to that of the semiconductor substrate.