Strained and strain control regions in optical devices

• US 10,637,210 B1
• Filed: 03/18/2019
• Issued: 04/28/2020
• Est. Priority Date: 11/05/2010
• Status: Active Grant

• Current Assignee: Kyocera SLD Laser Incorporated (Kyocera Corporation)
• Original Assignee: Soraa Laser Diode, Inc. (Kyocera Corporation)
• Inventors: Raring, James W., Poblenz Elsass, Christiane
• Primary Examiner(s): Menz, Laura M
• Application Number:
  US16/356,257
• Time in Patent Office: 407 Days
• CPC Class Codes: H01L 21/02389 Nitrides
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02507 Alternating layers, e.g. superlattice
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/12 with a stress relaxation structure, e.g. buffer layer
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/32 containing nitrogen
• CPC Class Codes: H01S 5/1082 with a special facet structure, e.g. structured, non planar, oblique
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/2018 Optical confinement, e.g. absorbing-, reflecting- or waveguide-layers
• CPC Class Codes: H01S 5/2031 characterized by special waveguide layers, e.g. asymmetric waveguide layers or defined bandgap discontinuities
• CPC Class Codes: H01S 5/2201 in a specific crystallographic orientation
• CPC Class Codes: H01S 5/3063 using Mg
• CPC Class Codes: H01S 5/3201 incorporating bulkstrain effects, e.g. strain compensation, strain related to polarisation
• CPC Class Codes: H01S 5/3202 grown on specifically orientated substrates, or using orientation dependent growth
• CPC Class Codes: H01S 5/320275 semi-polar orientation
• CPC Class Codes: H01S 5/3213 : asymmetric clading layers
• CPC Class Codes: H01S 5/3403 : having a strained layer structure in which the strain performs a special function, e.g. general strain effects, strain versus polarisation
• CPC Class Codes: H01S 5/3406 : including strain compensation
• CPC Class Codes: H01S 5/34333 : with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
• CPC Class Codes: H01S 5/34346 : characterised by the materials of the barrier layers

Abstract

An optical device has a gallium and nitrogen containing substrate including a surface region and a strain control region, the strain control region being configured to maintain a quantum well region within a predetermined strain state. The device also has a plurality of quantum well regions overlying the strain control region.

Claims

1. A system comprising:

a lighting apparatus; and

an optical device configured to provide light for the lighting apparatus, the optical device comprising;

a gallium and nitrogen containing substrate including a surface region and a first lattice constant;

a single or plurality of strained regions acting as an optical confinement region overlying the surface region, the strained region having a second lattice constant, the second lattice constant being larger than the first lattice constant;

a strain control region disposed between or above one or more of the strained regions having a third lattice constant, the third lattice constant being substantially equivalent to the second lattice constant, the strain control region being configured to maintain at least a quantum well region within a predetermined strain state;

a plurality of quantum well regions overlying the optical confinement region, each of the plurality of quantum well regions having a fourth lattice constant, the fourth lattice constant being substantially equivalent to the second lattice constant, whereupon the strain control region has a higher bandgap than the strained region and the quantum well regions.

2. The system of claim 1 wherein:

the strained region comprises an interface region between the substrate and the strain control region; and

the interface region comprises a plurality of dislocations.

3. The system of claim 1 wherein the surface region is configured in a {20-21} semi-polar orientation and the device is a laser diode device, or the surface region is configured to be in an off-set of a {20-21} orientation and the strained region is at least partially relaxed.

4. The system of claim 1 further comprising:

at least one barrier region sandwiched between a pair of quantum well regions;

each of the barrier regions comprising GaN, InGaN, AlGaN, or AlInGaN; and

each of the barrier regions ranges in thickness from 1.5 nm to 12 nm.

5. The system of claim 1 wherein:

the strained region comprises a single layer of InGaN;

the strained region has a thickness ranging from 20 to 80 nm with 2 to 20% InN content;

the strained region is overlaid with a single strain control layer comprised of GaN or AlGaN; and

the strain control layer has a thickness ranging from 2-20 nm with 2 to 40% AlN content.

6. The system of claim 1 wherein:

the strained region comprises multiple layers of GaN, AlN, AlInN, AlGaInN, or InGaN;

the multiple layers have a thickness ranging from 10 to 50 nm with 2 to 25% InN content;

the multiple layers are separated by strain control layers comprises of AlGaN;

the strain control layers have thickness ranging from 2-20 nm with 2 to 40% AlN content.

7. The system of claim 1 wherein:

the strained region comprises multiple layers of InGaN;

the InGaN layers have a thickness ranging from 10 to 50 nm with 2 to 25% InN content;

the InGaN layers are separated by strain control layers comprised of GaN;

there are a plurality of pairs of strained and strain control layers;

a thickness of the strained layers is equal or decreases with each subsequently deposited layer;

a composition of the strained layers is equal or increases in InN with each subsequently deposited layer.

8. A system comprising:

an optical module apparatus; and

an laser device configured to provide light for the optical module apparatus, the laser device comprising;

a gallium and nitrogen containing substrate including a surface region and a first lattice constant;

a single or plurality of strained regions acting as an optical confinement region overlying the surface region, the strained region having a second lattice constant, the second lattice constant being larger than the first lattice constant;

a strain control region disposed between or above one or more of the strained regions having a third lattice constant, the third lattice constant being substantially equivalent to the second lattice constant, the strain control region being configured to maintain at least a quantum well region within a predetermined strain state;

a plurality of quantum well regions overlying the optical confinement region, each of the plurality of quantum well regions having a fourth lattice constant, the fourth lattice constant being substantially equivalent to the second lattice constant, whereupon the strain control region has a higher bandgap than the strained region and the quantum well regions.

9. The system of claim 8 wherein the surface region is configured in a {20-21} semi-polar orientation and the device is a laser diode device, or the surface region is configured to be in an off-set of a {20-21} orientation and the strained region is at least partially relaxed.

10. The system of claim 8 further comprising:

at least one barrier region sandwiched between a pair of quantum well regions;

each of the barrier regions comprising GaN, InGaN, AlGaN, or AlInGaN; and

each of the barrier regions ranges in thickness from 1.5 nm to 12 nm.

11. The system of claim 8 wherein:

the strained region comprises a single layer of InGaN;

the strained region has a thickness ranging from 20 to 80 nm with 2 to 20% InN content;

the strained region is overlaid with a single strain control layer comprised of GaN or AlGaN; and

the strain control layer has a thickness ranging from 2-20 nm with 2 to 40% AlN content.

12. The system of claim 8 wherein:

the strained region comprises multiple layers of GaN, AlN, AlInN, AlGaInN, or InGaN;

the multiple layers have a thickness ranging from 10 to 50 nm with 2 to 25% InN content;

the multiple layers are separated by strain control layers comprises of AlGaN;

the strain control layers have thickness ranging from 2-20 nm with 2 to 40% AlN content.

13. The system of claim 8 wherein:

the strained region comprises multiple layers of InGaN;

the InGaN layers have a thickness ranging from 10 to 50 nm with 2 to 25% InN content;

the InGaN layers are separated by strain control layers comprised of GaN;

there are a plurality of pairs of strained and strain control layers;

a thickness of the strained layers is equal or decreases with each subsequently deposited layer;

a composition of the strained layers is equal or increases in InN with each subsequently deposited layer.

14. A laser diode device comprising:

a gallium and nitrogen containing substrate having a surface region and a first in-plane lattice constant;

one or more strained regions overlying the surface region of the gallium and nitrogen containing substrate, each of the one or more strained regions having a second in-plane lattice constant, the second in-plane lattice constant being smaller than a native in-plane lattice constant of the one or more strained regions;

at least one strain control region overlying at least one of the one or more strained regions, the at least one strain control region having a third in-plane lattice constant, the third in-plane lattice constant maintaining at least a quantum well region within a predetermined strain state;

a plurality of quantum well regions overlying the at least one strain control region, each of the plurality of quantum well regions having a fourth in-plane lattice constant, the fourth in-plane lattice constant being different than the first in-plane lattice constant, wherein the strain control region has a higher bandgap than the one or more strained regions and the plurality of quantum well regions.

15. The laser diode device of claim 14 wherein the second in-plane lattice constant is larger than the first in-plane lattice constant.

16. The laser diode device of claim 14 wherein the third in-plane lattice constant is substantially equivalent to the second in-plane lattice constant.

17. The laser diode device of claim 14 wherein the fourth in-plane lattice constant is substantially equivalent to the second in-plane lattice constant.

18. The laser diode device of claim 14 wherein the fourth in-plane lattice constant is substantially equivalent to the third in-plane lattice constant.

19. The laser diode device of claim 14 wherein the one or more strained regions provide optical confinement for the laser diode device.

20. The laser diode device of claim 14 wherein the one or more strained regions comprise a plurality of strained region, and the at least one strain control region comprises a plurality of strain control regions, and wherein adjacent ones of the plurality of strained regions are separated by one of the plurality of strain control regions.