JPH0366181A - Light-emitting diode - Google Patents

Abstract

PURPOSE:To reduce an irregularity in an engraved depth and to stabilize characteristics by a method wherein an etching stopper layer is formed between a second clad layer and a current-blocking layer and selective etchant is used in an engraving process. CONSTITUTION:A first clad layer, an active layer, a second clad layer, an etching stopper layer and a current-blocking layer are formed one after another on a substrate 1 to obtain an epitaxial water. Then, only the current-blocking layer 5 in one part is etched selectively by using photolithographic technique and a wet etching technique. An Al composition ratio of the currentblocking layer 5 is set at 0.3 or lower and an Al composition ratio of the stopper layer is set at 0.2 or lower; an etching operation is executed by using a hydrofluoric acid-based etchant. Thereby, a selective etching operation can be executed. In order to etch the stopper layer 8, a selective etching operation is executed by using ammonia and hydrogen peroxide-based etchant. After that, a cap layer 7 is grown by using an MOCVD growth method to form a SAS structure.

Description

[Detailed description of the invention] [Industrial application field] This is the start! No. 1 relates to a method of manufacturing a light emitting diode using an 8A8 structure among surface light emitting diodes used for optical communications and the like.

[Conventional technology]

FIG. 2 is a cross-sectional view showing the flow of the conventional manufacturing process of a light emitting diode.

In the figure, 14iN type GaA3 substrate, 2 is N type AJ?
GaA3 first cladding layer, 8 P-type AlGaAS active layer, number P-type A/GaAs second cladding layer, 5 N-type A/
A GaAs current blocking layer, 6 a stepped portion formed by deep etching, and 7 a P-type A/GaA9 cap layer.

Next, the manufacturing process will be explained. A first cladding layer 8. is formed on the GaA4 substrate 1 without trenches. Active layer 8. Second cladding layer4. A current blocking layer 5 is sequentially formed using a liquid phase epitaxial growth method to obtain a shrimp wafer as shown in FIG.

Next, a part of the wafer is selectively etched using photolithography and wet etching techniques ((Figure b1)).

After that, MootTD f! i. Extend the cap layer 7 using the length method to form the SAS structure as shown in the figure.

In the button etching process, the current blocking layer 5 is completely etched away to form a current injection region.

[Problem to be solved by the invention]

Conventional light emitting diodes were constructed as described above, so the depth of the digging etching was determined by the composition of the etching solution,
Although it is controlled by temperature, button and etching time, the controllability of wet etching is about ±20%, and variations in properties due to variations in digging depth have been a problem.

This invention was made to solve the above-mentioned problems, and aims to provide a light emitting diode with stable characteristics by reducing variations in digging depth.

[Means to solve the problem]

The light emitting diode according to the present invention has an eratin guest layer formed between the second cladding layer and the current blocking layer, and uses a selective etchant in the digging process.

[Effect]

In the current blocking layer 5 and the etching stopper layer according to the present invention, variations in digging depth are reduced by sequentially and selectively etching only both layers with gold.

[Implementation row]

Hereinafter, an embodiment of the present invention will be described. 1st
The figure is a cross-sectional view showing the flow of the manufacturing process of a light emitting diode with an SAS structure according to one embodiment of the present invention. 8 is P type A/GaAs active layer, 4 is P type A/
GaA4 second cladding layer, 5 is N-type A/GaAg' [flow blocking layer, 6 is a step portion formed by digging etching, 7 is P-type AlGaA3 cap layer, 8t/i etching stopper layer. be.

Next, the manufacturing process will be explained. 1. GaA3 substrate 1
A first cladding layer, an active layer, a second cladding layer, an etching stopper, and a current blocking layer are sequentially formed thereon using the Vcfi phase epitaxial growth method as in the conventional method, as shown in the fJL1 diagram. Obtain epiwafers.

Next, only a part of the current blocking layer 5 is selectively etched with gold using photolithography and wet etching techniques ((Figure b1)).

Selective etching is possible by setting the A/composition ratio of the current blocking layer 5 to 0.8 or more and the At@ffl ratio of the stopper layer to 0.2 or less, and performing etching using a hydrofluoric acid-based etchant. .

Furthermore, in order to etch the stopper layer 8, selective etching is performed using an ammonia-hydrogen peroxide based elaschanter (FIG. (0)).

Thereafter, the cap layer 7 is lengthened using the MOOUD li length method to form a SAS structure as shown in the first diagram.

〔Effect of the invention〕

As described above, according to the present invention, by newly forming the etching stopper layer and using a selective etchant, the variation in the digging depth can be reduced to ±5% or less, and the characteristics can be stabilized. effective.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the manufacturing process of a light emitting diode according to an embodiment of the present invention, and FIG. 2 is a sectional view showing the manufacturing process of a conventional light emitting diode. VC is drawn, 1 is the GaAB substrate, 2 is the first cladding layer, 81d is the active layer, 4 is the second cladding layer, 5 is the current blocking layer, 6 is the stepped portion by digging, 7 is the cap layer, 8I
The RI etching stopper layer metal is shown. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In an AlGaAS-based SAS structure LED, a first cladding layer of a first conductivity type, a second cladding layer of a first conductivity type are formed on a semiconductor substrate of a first conductivity type.
An active layer of a conductivity type, a second cladding layer of a second conductivity type, a stopper layer of a second conductivity type, and a current blocking layer of a first conductivity type are sequentially formed, and a part of the current blocking layer of the first conductivity type is formed. After removing it by etching using a selective etchant, a part of the stopper layer of the second conductivity type was removed by etching using an etchant with different selectivity, and further, a cap layer of the second conductivity type was formed thereon. A light emitting diode characterized by: