# US 11,444,434 B2 · Nitride semiconductor multilayer structure, light emitting element, light source apparatus, and method for producing nitride semiconductor multilayer structure

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- Number: US 11,444,434 B2
- Document ID: US11444434B2
- Status: Granted
- Kind: B2
- Application number: 16/749,001
- Filed: 2020-01-22
- Published: 2020-07-30
- Granted: 2022-09-13
- Earliest claimed: 2019-01-25
- Assignees: Ricoh Company, Ltd.
- Applicants: Takeshi Kawashima
- Inventors: Takeshi Kawashima
- Web page: https://patentgrep.com/patent/US11444434B2

## CPC

- H01S 5/34333: {with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser}
- H01S 5/18308: {having a special structure for lateral current or light confinement}
- H01S 5/18369: {based on dielectric materials}
- H01S 5/2216: {nitrides}
- H10H 20/01335: {the light-emitting regions comprising nitride materials}
- H10H 20/0137: {the light-emitting regions comprising nitride materials}
- H10H 20/816: having carrier transport control structures, e.g. highly-doped semiconductor layers or current-blocking structures
- H10H 20/8215: {characterised by crystalline imperfections, e.g. dislocations; characterised by the distribution of dopants, e.g. delta-doping}
- H10H 20/825: containing nitrogen, e.g. GaN
- H01S 5/04252: {characterised by the material}
- H01S 5/04253: {having specific optical properties, e.g. transparent electrodes}
- H01S 5/04256: {characterised by the configuration}
- H01S 5/04257: {having positive and negative electrodes on the same side of the substrate}
- H01S 5/18325: {Between active layer and substrate}
- H01S 5/18341: {Intra-cavity contacts}
- H01S 5/3095: {Tunnel junction}
- H01S 2301/176: Specific passivation layers on surfaces other than the emission facet
- H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

A nitride semiconductor multilayer structure includes a first nitride semiconductor layer; a second nitride semiconductor layer; and a third nitride semiconductor layer formed between the first nitride semiconductor layer and the second nitride semiconductor layer. The third nitride semiconductor layer includes a first region and a second region that surrounds the first region in a same plane, and an indium content of the second region is lower than an indium content of the first region.

## Claims

### Claim 1

A nitride semiconductor multilayer structure comprising:
a first nitride semiconductor layer;
a second nitride semiconductor layer; and
a third nitride semiconductor layer formed between the first nitride semiconductor layer and the second nitride semiconductor layer,
wherein the third nitride semiconductor layer includes a first region and a second region, that surrounds the first region in a same plane,
the first region includes at least indium and nitrogen,
the second region includes at least nitrogen, and
an indium content of the second region is greater than or equal to zero and lower than the indium content of the first region.

### Claim 2 (depends on 1)

The nitride semiconductor multilayer structure according to claim 1, wherein a band gap of the second region is, larger than a band gap of each of the first nitride semiconductor layer, the second nitride semiconductor layer, and the first region by 0.5 eV or more.

### Claim 3 (depends on 1)

The nitride semiconductor multilayer structure according, to claim 1, wherein the third, nitride semiconductor layer has a thickness of 20 nm or more.

### Claim 4 (depends on 1)

The nitride semiconductor multilayer structure according to claim 1, wherein the first region and the second region each include Al.

### Claim 5 (depends on 4)

The nitride semiconductor multilayer structure according to claim 4, wherein the first region and the second region are each formed of AlInN or AlGaInN.

### Claim 6 (depends on 1)

A light emitting element comprising,
the nitride semiconductor multilayer structure according to claim 1, the nitride semiconductor multilayer structure including an active layer that emits light.

### Claim 7 (depends on 6)

The light emitting element according to claim 6, wherein the nitride semiconductor multilayer structure includes a resonator structure that causes the light emitted from the active layer to resonate.

### Claim 8 (depends on 6)

A light source apparatus comprising,
the light emitting element according to claim 6.

### Claim 9

A nitride semiconductor multilayer structure comprising:
a first nitride semiconductor layer;
a second nitride semiconductor layer; and
a third nitride semiconductor layer formed between the first nitride semiconductor layer and the second nitride semiconductor layer,
wherein the third nitride semiconductor layer includes a first region and a second region that surrounds the first region in a same plane, and
the second region has a largest band gap, among the first nitride semiconductor layer, the second nitride semiconductor layer, the first region, and the second region.

### Claim 10

A method for producing a nitride semiconductor multilayer structure, the method comprising:
forming a first nitride semiconductor layer, a second nitride semiconductor layer, and a third nitride semiconductor layer on a substrate, the third nitride semiconductor layer being formed between the first nitride semiconductor layer and the second nitride semiconductor layer and including at least an indium and a nitrogen; and
performing heat treatment so as to reduce an indium content of a part of the third nitride semiconductor and form, in the third nitride semiconductor layer, a first region and a second region that surrounds the first region in a same plane, the first region including at least the indium and a nitrogen and allowing an electric current to flow through the first region between the first nitride semiconductor layer and the second, nitride semiconductor layer, and the second region including at least the nitrogen and preventing the electric current from flowing through the second region,
wherein the indium content of the second region is greater than or equal to zero and lower than the indium content of the first region.