# US 5,710,440 A · Semiconductor light emitting element with In GaAlP active layer of specified thickness

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- Number: US 5,710,440 A
- Document ID: US5710440A
- Status: Granted
- Kind: A
- Application number: 08/600,295
- Filed: 1996-02-12
- Granted: 1998-01-20
- Earliest claimed: 1995-02-15
- Assignees: Mitsubishi Cable Industries, Ltd.
- Inventors: Hiroaki Okagawa; Takayuki Hashimoto; Keiji Miyashita; Tomoo Yamada; Kazuyuki Tadatomo
- Web page: https://patentgrep.com/patent/US5710440A

## CPC

- H10H 20/824: comprising only Group III-V materials, e.g. GaP
- H10H 20/816: having carrier transport control structures, e.g. highly-doped semiconductor layers or current-blocking structures
- H10H 20/8242: {characterised by the dopants}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

A semiconductor light emitting element comprising an n-type semiconductor substrate and a light emitting part comprising an n-type cladding layer composed of an InGaAlP compound semiconductor material, an active layer and a p-type cladding layer formed in that order from the substrate side by double heterojunction, wherein said semiconductor light emitting element satisfies at least one of the following conditions: A. the thickness of said active layer being greater than 0.75 .mu.m and not more than 1.5 .mu.m, and B. the thickness of said p-type cladding layer being 0.5 .mu.m-2.0 .mu.m. According to the light emitting element of the present invention, an overflow of electron into the p-type cladding layer can be suppressed by setting the thickness of the active layer and the p-type cladding layer to fall within the above-mentioned specific ranges, as a result of which the element shows luminous efficiency peaked within the specified range.

## Claims

### Claim 1

A semiconductor light emitting element comprising an n-type semiconductor substrate and a light emitting part composed of an InGaAlP compound semiconductor material, said light emitting part comprising an n-type cladding layer, an active layer and a p-type cladding layer in this order from the substrate side to form a double heterojunction, and said active layer having a thickness of greater than 0.75 .mu.m and not more than 1.5 .mu.m.

### Claim 2 (depends on 1)

The semiconductor light emitting element of claim 1, wherein the semiconductor substrate is a GaAs substrate and InGaAlP compound semiconductor material is defined by formula: In.sub.0.49 (Ga.sub.1-x Al.sub.x).sub.0.51 P(0.ltoreq.x.ltoreq.1).

### Claim 3 (depends on 1)

The semiconductor light emitting element of claim 1, wherein the carrier concentration of the p-type cladding layer is 5.times.10.sup.16 cm.sup.-3 -5.times.10.sup.17 cm.sup.-3.

### Claim 4 (depends on 1)

The semiconductor light emitting element of claim 1, wherein the thickness of the active layer is 1.1 .mu.m-1.3 .mu.m.

### Claim 5 (depends on 1)

The semiconductor light emitting element of claim 1, wherein a current diffusing layer is further formed on the p-type cladding layer.

### Claim 6

A semiconductor light emitting element comprising an n-type semiconductor substrate and a light emitting part composed of an InGaAlP compound semiconductor material, said light emitting part comprising an n-type cladding layer, an active layer and a p-type cladding layer in this order from the substrate side to form a double heterojunction, said active layer having a thickness of greater than 0.75 .mu.m and not more than 1.5 .mu.m, and said p-type cladding layer having a thickness of 0.5-2.0 .mu.m.

### Claim 7 (depends on 6)

The semiconductor light emitting element of claim 6, wherein the semiconductor substrate is a GaAs substrate and the InGaAlP compound semiconductor material is defined by the formula: In.sub.0.49 (Ga.sub.1-x Al.sub.x).sub.0.51 P (0.ltoreq.x.ltoreq.1).

### Claim 8 (depends on 6)

The semiconductor light emitting element of claim 6, wherein the carrier concentration of the p-type cladding layer is 5.times.10.sup.16 cm.sup.-3 -5.times.10.sup.17 cm.sup.-3.

### Claim 9 (depends on 6)

The semiconductor light emitting element of claim 6, wherein the thickness of the active layer is 1.1 .mu.m-1.3 .mu.m.

### Claim 10 (depends on 6)

The semiconductor light emitting element of claim 6, wherein a current diffusing layer is further formed on the p-type cladding layer.