# US 12,224,557 B2 · Semiconductor optical device and method of manufacturing the same

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- Number: US 12,224,557 B2
- Document ID: US12224557B2
- Status: Granted
- Kind: B2
- Application number: 17/501,226
- Filed: 2021-10-14
- Published: 2022-04-28
- Granted: 2025-02-11
- Earliest claimed: 2020-10-28
- Assignees: Sumitomo Electric Industries, Ltd.
- Applicants: Sumitomo Electric Industries, Ltd.
- Inventors: Naoki Fujiwara; Akira Furuya; Naoya Kono
- Web page: https://patentgrep.com/patent/US12224557B2

## CPC

- H01S 5/06258: {with DFB-structure}
- H01S 5/125: Distributed Bragg reflector [DBR] lasers
- H01S 5/06256: {with DBR-structure}
- H01S 5/1028: {Coupling to elements in the cavity, e.g. coupling to waveguides adjacent the active region, e.g. forward coupled [DFC] structures}
- H01S 5/1231: {Grating growth or overgrowth details}
- H01S 5/2206: {based on III-V materials}
- H01S 5/2222: {having special electric properties}
- H01S 5/1039: {Details on the cavity length}
- H01S 5/227: Buried mesa structure {; Striped active layer}
- H01S 5/34306: {emitting light at a wavelength longer than 1000nm, e.g. InP based 1300 and 1500nm lasers}
- 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

## Abstract

A semiconductor optical device in which a light emitting region that emits light and a reflecting region that reflects the light to the light emitting region side are integrated includes a core layer that is provided in the light emitting region, and a waveguide layer that is provided in the reflecting region, that is optically coupled to the core layer, and that has a band gap that is larger than energy of the light. The reflecting region has a first thyristor that overlaps the waveguide layer in a direction that intersects a propagation direction of the light.

## Claims

### Claim 1

A semiconductor optical device in which a light emitting region that emits light and a reflecting region that reflects the light to the light emitting region side are integrated, the semiconductor optical device comprising:
a core layer that is provided in the light emitting region;
a waveguide layer that is provided in the reflecting region, that is optically coupled to the core layer, and that has a band gap that is larger than energy of the light;
a first semiconductor layer of a first conductivity type that is provided below the core layer and the waveguide layer;
a second semiconductor layer of a second conductivity type that is provided on the waveguide layer, the second conductivity type differing from the first conductivity type;
a third semiconductor layer of the first conductivity type that is provided on the second semiconductor layer;
a fourth semiconductor layer of the second conductivity type that is provided on the core layer and above the second semiconductor layer; and
a first thyristor in the reflecting region that overlaps the waveguide layer in a first direction that is a direction that intersects a propagation direction of the light, wherein
the first semiconductor layer and the core layer form a first mesa that protrudes in the first direction,
the first semiconductor layer and the waveguide layer form a second mesa that protrudes in the first direction,
the first mesa and the second mesa extend in the propagation direction of the light and are adjacent to each other,
the first thyristor is formed at a position that overlaps the second mesa in the first direction, and on two sides of the second mesa,
in the reflecting region, the second semiconductor layer and the third semiconductor layer are each provided on the two sides of the second mesa and above the second mesa,
the fourth semiconductor layer is provided on the third semiconductor layer so as to cover an upper side of the second mesa and the two sides of the second mesa, and
the first semiconductor layer, the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer form the first thyristor at the position that overlaps the second mesa, and on the two sides of the second mesa.

### Claim 2 (depends on 1)

The semiconductor optical device according to claim 1, wherein
in the light emitting region, the second semiconductor layer and the third semiconductor layer are each provided on two sides of the first mesa,
the fourth semiconductor layer is provided on the third semiconductor layer and above the first mesa, and
the first semiconductor layer, the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer form a second thyristor on the two sides of the first mesa.

### Claim 3 (depends on 1)

The semiconductor optical device according to claim 1, wherein
the first mesa has a first diffraction grating,
the second mesa has a second diffraction grating, and
a shape of the first diffraction grating is the same as a shape of the second diffraction grating.

### Claim 4 (depends on 1)

The semiconductor optical device according to claim 1, wherein
a first electrode and a second electrode are provided at the light emitting region, and
at least one of the first electrode and the second electrode is not provided at the reflecting region.

### Claim 5 (depends on 1)

The semiconductor optical device according to claim 1, wherein
the first semiconductor layer and the third semiconductor layer each include n-type indium phosphide, and
the second semiconductor layer and the fourth semiconductor layer each include p-type indium phosphide.

### Claim 6

A method of manufacturing a semiconductor optical device in which a light emitting region that emits light and a reflecting region that reflects the light to the light emitting region side are integrated, the method comprising:
growing, on a first semiconductor layer of a first conductivity type, a core layer in the light emitting region;
growing, on the first semiconductor layer in the reflecting region, a waveguide layer that is optically coupled to the core layer and that has a band gap that is larger than energy of the light;
forming, in the reflecting region, a first thyristor that overlaps the waveguide layer in a first direction that is a direction that intersects a propagation direction of the light;
growing, on the waveguide layer, a first embedding layer of a second conductivity type, the second conductivity type differing from the first conductivity type;
etching the first semiconductor layer and the core layer to form a first mesa that protrudes in the first direction;
etching the first semiconductor layer and the waveguide layer to form a second mesa that protrudes in the first direction;
growing, on the waveguide layer, a second embedding layer of the second conductivity type, and forming a second semiconductor layer with the first embedding layer and the second embedding layer;
changing a dopant from the second conductivity type to the first conductivity type and a third semiconductor layer of the first conductivity type on the second semiconductor layer;
growing a fourth semiconductor layer of the second conductivity type on the core layer and above the second semiconductor layer; and
forming, a first thyristor that overlaps the waveguide layer in the first direction, using the first semiconductor layer, the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer in the reflecting region at a position that overlaps the second mesa in the first direction, and on two sides of the second mesa, wherein
the first mesa and the second mesa extend in the propagation direction of the light and are adjacent to each other,
in the reflecting region, the second semiconductor layer and the third semiconductor layer are each provided on the two sides of the second mesa and above the second mesa, and
the fourth semiconductor layer is provided on the third semiconductor layer so as to cover an upper side of the second mesa and the two sides of the second mesa.

### Claim 7 (depends on 6)

The method of manufacturing the semiconductor optical device according to claim 6, comprising:
etching the core layer and the waveguide layer to form a first diffraction grating in the core layer and a second diffraction grating in the waveguide layer, the second diffraction grating being adjacent to the first diffraction grating.

### Claim 8

A semiconductor optical device in which a light emitting region that emits light and a reflecting region that reflects the light to the light emitting region side are integrated, the semiconductor optical device comprising:
a core layer that is provided in the light emitting region;
a waveguide layer that is provided in the reflecting region, that is optically coupled to the core layer, and that has a band gap that is larger than energy of the light;
a first semiconductor layer of a first conductivity type that is provided below the core layer and the waveguide layer;
a second semiconductor layer of a second conductivity type that is provided on the waveguide layer, the second conductivity type differing from the first conductivity type;
a third semiconductor layer of the first conductivity type that is provided on the second semiconductor layer;
a fourth semiconductor layer of the second conductivity type that is provided on the core layer and above the second semiconductor layer; and
a first thyristor in the reflecting region that overlaps the waveguide layer in a first direction that is a direction that intersects a propagation direction of the light, wherein
the first semiconductor layer and the core layer form a first mesa that protrudes in the first direction,
the first semiconductor layer and the waveguide layer form a second mesa that protrudes in the first direction,
the first mesa and the second mesa extend in the propagation direction of the light and are adjacent to each other,
the first thyristor is formed at a position that overlaps the second mesa in the first direction, and on two sides of the second mesa,
in the light emitting region, the second semiconductor layer and the third semiconductor layer are each provided on two sides of the first mesa,
the fourth semiconductor layer is provided on the third semiconductor layer and above the first mesa, and
the first semiconductor layer, the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer form a second thyristor on the two sides of the first mesa.

### Claim 9

A method of manufacturing a semiconductor optical device in which a light emitting region that emits light and a reflecting region that reflects the light to the light emitting region side are integrated, the method comprising:
growing, on a first semiconductor layer of a first conductivity type, a core layer in the light emitting region;
growing, on the first semiconductor layer in the reflecting region, a waveguide layer that is optically coupled to the core layer and that has a band gap that is larger than energy of the light;
forming, in the reflecting region, a first thyristor that overlaps the waveguide layer in a first direction that is a direction that intersects a propagation direction of the light;
growing, on the waveguide layer, a first embedding layer of a second conductivity type, the second conductivity type differing from the first conductivity type;
etching the first semiconductor layer and the core layer to form a first mesa that protrudes in the first direction;
etching the first semiconductor layer and the waveguide layer to form a second mesa that protrudes in the first direction;
growing, on the waveguide layer, a second embedding layer of the second conductivity type, and forming a second semiconductor layer with the first embedding layer and the second embedding layer;
changing a dopant from the second conductivity type to the first conductivity type and a third semiconductor layer of the first conductivity type on the second semiconductor layer;
growing a fourth semiconductor layer of the second conductivity type on the core layer and above the second semiconductor layer; and
forming, in the reflecting region using the first semiconductor layer, the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer, a first thyristor that overlaps the waveguide layer in the first direction and at a position that overlaps the second mesa in the first direction, and on two sides of the second mesa, wherein
the first mesa and the second mesa extend in the propagation direction of the light and are adjacent to each other,
in the light emitting region, the second semiconductor layer and the third semiconductor layer are each provided on two sides of the first mesa,
the fourth semiconductor layer is provided on the third semiconductor layer and above the first mesa, and
the first semiconductor layer, the second semiconductor layer, the third semiconductor layer, and the fourth semiconductor layer form a second thyristor on the two sides of the first mesa.