# US 2008/0187018 A1 · Distributed feedback lasers formed via aspect ratio trapping

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2008/0187018 A1
- Document ID: US20080187018A1
- Status: Published application
- Kind: A1
- Application number: 11/875,177
- Filed: 2007-10-19
- Published: 2008-08-07
- Earliest claimed: 2006-10-19
- Assignees: AmberWave Systems Corporation
- Inventors: Jizhong Li
- Web page: https://patentgrep.com/patent/US20080187018A1

## CPC

- H10H 20/817: characterised by the crystal structures or orientations, e.g. polycrystalline, amorphous or porous
- H01S 5/223: Buried stripe structure {(H01S5/227 takes precedence)}
- H01S 5/2237: {with a non-planar active layer}
- H01S 5/24: having a grooved structure, e.g. V-grooved {, crescent active layer in groove, VSIS laser}
- H10H 20/0125: {with a substrate not being Group II-VI materials}
- H10H 20/0133: {with a substrate not being Group III-V materials}
- H10H 20/01335: {the light-emitting regions comprising nitride materials}
- H10H 20/018: {Bonding of wafers}
- H10H 20/812: within the light-emitting regions, e.g. having quantum confinement structures
- H10H 20/815: having stress relaxation structures, e.g. buffer layers
- H10H 20/819: characterised by their shape, e.g. curved or truncated substrates
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/271: {characterised by the preparation of substrate for selective deposition}
- H10P 14/276: {Lateral overgrowth}
- H10P 14/2905: {Silicon, silicon germanium or germanium}
- H10P 14/3404: {being Group IVA materials}
- H10P 14/3414: {being group IIIA-VIA materials}
- H10P 14/3421: {Arsenides}
- H01S 5/0207: {Substrates having a special shape}
- H01S 5/021: {Silicon based substrates}
- H01S 5/0218: {Substrates comprising semiconducting materials from other groups of the Periodic Table than the materials of the active layer}
- H01S 5/2234: {having a structured substrate surface}
- H01S 5/227: Buried mesa structure {; Striped active layer}
- H01S 5/3202: {grown on specifically orientated substrates, or using orientation dependent growth}
- H01S 2304/12: Pendeo epitaxial lateral overgrowth [ELOG], e.g. for growing GaN based blue laser diodes
- H10H 20/813: having a plurality of light-emitting regions, e.g. multi-junction LEDs or light-emitting devices having photoluminescent regions within the bodies
- H10H 20/821: of the light-emitting regions, e.g. non-planar junctions
- H10P 14/3441: {Conductivity type}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- 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
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Structures including dielectric diffraction gratings. In some embodiments, laser devices include diffraction gratings defined by openings formed in a dielectric material.

## Claims

### Claim 1

A method of making a laser diode, the method comprising the steps of:
forming a dielectric layer over a top surface of the substrate comprising a first semiconductor material;
defining a plurality of openings in the dielectric layer, the openings extending to the top surface of the substrate;
forming a second semiconductor material in the openings; and
defining a plurality of layers over the second semiconductor material and the dielectric layer to form the laser diode,
wherein portions of the dielectric layer define a diffraction grating.

### Claim 2 (depends on 1)

The method of claim 1, wherein the diffraction grating has a width and a spacing selected to provide a duty cycle ranging from 20% to 50%.

### Claim 3 (depends on 1)

The method of claim 1, wherein defining the plurality of openings comprises reactive ion etching.

### Claim 4 (depends on 1)

The method of claim 1, wherein forming the second semiconductor material comprises selective epitaxy.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first semiconductor material comprises silicon and the second semiconductor material comprises at least one of a III-V compound or a II-VI compound.

### Claim 6 (depends on 1)

The method of claim 1, wherein the plurality of semiconductor layers comprises at least one of a cladding layer, a grating layer, a graded spacer layer, a graded confining layer, a quantum well region, or a cap layer.

### Claim 7 (depends on 1)

The method of claim 1, wherein the laser diode is a distributed feedback laser diode.

### Claim 8 (depends on 1)

The method of claim 1, further comprising defining a bottom contact layer over a bottom surface of the substrate.

### Claim 9 (depends on 1)

The method of claim 1, wherein a bottom portion of the second semiconductor material comprises lattice-mismatch defects and a top portion of the second semiconductor material is substantially free of lattice-mismatch defects.

### Claim 10 (depends on 9)

The method of claim 9, wherein each of the openings has a height sufficient for trapping a majority of the lattice-mismatch defects within the opening.

### Claim 11 (depends on 1)

The method of claim 1, wherein each of the plurality of openings has a width less than or equal to a height thereof.

### Claim 12

A semiconductor device comprising:
a plurality of openings defined in a dielectric layer disposed above a crystalline substrate comprising a first semiconductor material;
a diffraction grating defined by portions of the dielectric layer disposed between the openings;
a second crystalline material disposed within each of the openings, the second crystalline material having a lattice mismatch with the substrate, and a majority of defects arising from lattice mismatch between the second material and the substrate exiting at a surface of the second material within each of the openings; and
a plurality of semiconductor layers disposed above the second crystalline material and the diffraction grating, the plurality of semiconductor layers forming a laser diode.

### Claim 13 (depends on 12)

The device of claim 12 wherein the first semiconductor material comprises silicon.

### Claim 14 (depends on 12)

The device of claim 12 wherein the second crystalline material comprises at least one of a III-V compound or a II-VI compound.

### Claim 15 (depends on 12)

The device of claim 12 wherein the diffraction grating provides a duty cycle ranging from 20% to 50%.

### Claim 16 (depends on 12)

The device of claim 12 wherein the laser diode is a distributed feedback laser.

### Claim 17

A distributed feedback laser device comprising:
a dielectric diffraction grating disposed over a crystalline substrate; and
a plurality of layers disposed above the diffraction grating,
wherein the layers define a laser diode, and at least some of the layers comprise a III-V material lattice-mismatched to the crystalline substrate.

### Claim 18 (depends on 17)

The device of claim 17 wherein the diffraction grating comprises a dielectric layer defining a plurality of openings.

### Claim 19 (depends on 18)

The device of claim 18, further comprising a crystalline material disposed within the openings, the crystalline material having a lattice constant mismatched to a lattice constant of the crystalline substrate.

### Claim 20 (depends on 19)

The device of claim 19, further comprising a contact disposed on a bottom side of the crystalline substrate.

### Claim 21 (depends on 19)

The device of claim 19, further comprising an input electrode and an output electrode disposed on a single side of the crystalline substrate.

### Claim 22 (depends on 19)

The device of claim 19, wherein a top portion of the crystalline material is substantially free of defects.

### Claim 23 (depends on 17)

The device of claim 17, wherein the crystalline substrate comprises a group IV material.

### Claim 24

A method of making a laser diode, the method comprising the steps of:
forming a dielectric layer over a crystalline substrate comprising a first semiconductor material;
forming a first diffraction grating by:
defining a first plurality of openings in the dielectric layer above a top surface of the crystalline substrate, the first diffraction grating generating a first output wavelength;
forming a second diffraction grating by:
defining a second plurality of openings in the dielectric layer above the top surface of the crystalline substrate, the second diffraction grating generating a second output wavelength; and
defining a plurality of layers over the first and second diffraction gratings to form the laser diode.

### Claim 25

A distributed feedback laser device comprising:
a dielectric layer disposed over a crystalline substrate comprising a first semiconductor material;
a first diffraction grating defined by a first plurality of openings in the dielectric layer above a top surface of the crystalline substrate, the first diffraction grating generating a first output wavelength;
a second diffraction grating defined by a second plurality of openings in the dielectric layer above the top surface of the crystalline substrate, the second diffraction grating generating a second output wavelength; and
a plurality of layers disposed over the first and second diffraction gratings defining a distributed feedback laser device active region.