# US 12,002,897 B2 · Infrared detecting device

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- Number: US 12,002,897 B2
- Document ID: US12002897B2
- Status: Granted
- Kind: B2
- Application number: 18/331,173
- Filed: 2023-06-08
- Published: 2024-04-04
- Granted: 2024-06-04
- Earliest claimed: 2020-03-10
- Assignees: Asahi Kasei Microdevices Corporation
- Applicants: Asahi Kasei Microdevices Corporation
- Inventors: Osamu Morohara; Yoshiki Sakurai; Hiromi Fujita; Hirotaka Geka
- Web page: https://patentgrep.com/patent/US12002897B2

## CPC

- G01J 5/20: using resistors, thermistors or semiconductors sensitive to radiation, e.g. photoconductive devices
- H10F 30/222: the potential barrier being a PN heterojunction
- G01J 5/0853: {having infrared absorbers other than the usual absorber layers deposited on infrared detectors like bolometers, wherein the heat propagation between the absorber and the detecting element occurs within a solid}
- H10F 30/223: the potential barrier being a PIN barrier
- H10F 71/1272: {comprising at least three elements, e.g. GaAlAs or InGaAsP}
- H10F 77/1248: {having three or more elements, e.g. GaAlAs, InGaAs or InGaAsP}
- H10F 77/146: {Superlattices; Multiple quantum well structures}
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

An infrared detecting device is provided. The infrared detecting device includes: a semiconductor substrate; a first layer having a first conductivity type on the semiconductor substrate; a light receiving layer on the first layer; and a second layer having a second conductivity type on the light receiving layer. A part of the first layer, the light receiving layer, and the second layer form a mesa structure. The second layer contains AlzIn1-zSb (0.05<z<0.18). The side surfaces and an upper surface of the mesa structure are covered with the protective layer. A part of an upper surface of the second layer that forms an interface between the second layer and the protective layer has an oxide layer made of a constituent material of the second layer. The oxide layer includes an oxide of Al and has no oxide of Sb.

## Claims

### Claim 1

An infrared detecting device comprising:
a semiconductor substrate;
a first layer having a first conductivity type on the semiconductor substrate;
a light receiving layer on the first layer; and
a second layer having a second conductivity type on the light receiving layer,
wherein a part of the first layer, the light receiving layer, and the second layer form a mesa structure,
the second layer contains AlzIn1-zSb (0.05<z<0.18),
the side surfaces and an upper surface of the mesa structure are covered with the protective layer,
a part of an upper surface of the second layer that forms an interface between the second layer and the protective layer has an oxide layer made of a constituent material of the second layer, and
the oxide layer includes an oxide of Al and has no oxide of Sb.

### Claim 2 (depends on 1)

The infrared detecting device according to claim 1, wherein the light receiving layer contains AlxIn1-xSb (0.05<x<0.18).

### Claim 3 (depends on 1)

The infrared detecting device according to claim 1, wherein a layer that is included in the second layer and is in contact with the light receiving layer is made of a material having a band gap larger than a band gap of the light receiving layer.

### Claim 4 (depends on 1)

The infrared detecting device according to claim 1, wherein a material of a layer that is included in the second layer and is in contact with the light receiving layer is AlyIn1-ySb (0.10<y−x<0.40).

### Claim 5 (depends on 1)

The infrared detecting device according to claim 1,
wherein the semiconductor substrate is a GaAs substrate, and
a material of a layer that is included in the first layer and is in contact with the GaAs substrate is InSb.

### Claim 6 (depends on 1)

The infrared detecting device according to claim 1,
wherein the first layer has a layer containing Ala(1)In1-a(1)Sb, a layer with a film thickness of tb(1) [nm] containing Alb(1)In1-b(1)Sb, and a layer containing Ala(2)In1-a(2)Sb in order stated,
where tb(1), a(1), a(2) and b(1) satisfy the following relations:
0<tb(1)≤2360×(b(1)−a(1))−240(0.11≤b(1)−a(1)≤0.19),
0<tb(1)≤−1215×(b(1)−a(1))+427(0.19<b(1)−a(1)≤0.33),
0<tb(1)≤2360×(b(1)−a(2))−240(0.11≤b(1)−a(2)≤0.19),
0<tb(1)≤−1215×(b(1)−a(2))+427(0.19<b(1)−a(2)≤0.33),
0<a(1)<0.18, and
0<a(2)<0.18.

### Claim 7 (depends on 6)

The infrared detecting device according to claim 6,
wherein a layer that is included in the first layer and is in contact with the light receiving layer is AlpIn1-pSb with a film thickness of tp [nm],
where |p−x|×tp≤|b(1)−a(1)|×tb(1), and
p>x+0.05.

### Claim 8 (depends on 6)

The infrared detecting device according to claim 6,
wherein the layer that is included in the second layer and is in contact with the light receiving layer is AlqIn1-qSb with a film thickness of tq [nm],
where |q−x|×tq≤|b(1)−a(1)|×tb(1), and
q>x+0.05.