Facet on a gallium and nitrogen containing laser diode

• US 10,559,939 B1
• Filed: 03/27/2018
• Issued: 02/11/2020
• Est. Priority Date: 04/05/2012
• Status: Active Grant

• Current Assignee: Kyocera SLD Laser Incorporated (Kyocera Corporation)
• Original Assignee: Soraa Laser Diode, Inc. (Kyocera Corporation)
• Inventors: Raring, James W., Huang, Hua, Skahan, Phillip, Oh, Sang-Ho, Yonkee, Ben, Sztein, Alexander, Wei, Qiyuan
• Primary Examiner(s): Carter, Michael
• Application Number:
  US15/937,740
• Time in Patent Office: 686 Days
• CPC Class Codes: H01S 2304/04 MOCVD or MOVPE
• CPC Class Codes: H01S 5/0203 Etching
• CPC Class Codes: H01S 5/028 Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
• CPC Class Codes: H01S 5/0282 Passivation layers or treatments
• CPC Class Codes: H01S 5/0287 Facet reflectivity
• CPC Class Codes: H01S 5/0425 Electrodes, e.g. characterised by the structure
• CPC Class Codes: H01S 5/2009 by using electron barrier layers
• CPC Class Codes: H01S 5/22 having a ridge or stripe structure
• CPC Class Codes: H01S 5/3202 grown on specifically orientated substrates, or using orientation dependent growth
• CPC Class Codes: H01S 5/32025 non-polar orientation
• CPC Class Codes: H01S 5/320275 semi-polar orientation
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser

Abstract

Laser diode technology incorporating etched facet mirror formation and optical coating techniques for reflectivity modification to enable ultra-high catastrophic optical mirror damage thresholds for high power laser diodes.

Claims

1. A laser device, comprising:

a substrate having a surface;

a gallium and nitrogen containing cavity region overlying the surface, the gallium and nitrogen containing cavity region characterized by a first end and a second end, the first end comprising a first etched facet and the second end comprising a second etched facet; and

a passivation layer comprising a polycrystalline layer of Al₂O₃ directly contacting the first etched facet, wherein the passivation layer is heteroepitaxial and has a crystalline orientation of the first etched facet, and an interface between the passivation layer and the first etched facet is substantially contaminant free.

2. The laser device of claim 1, wherein the passivation layer further comprises a single-crystalline film of Al₂O₃ on the polycrystalline layer of Al₂O₃.

3. The laser device of claim 1, wherein the first etched facet has a surface roughness that varies by greater than at least one of about 10 nm, 30 nm, or 50 nm.

4. The laser device of claim 1, further comprising one or more reflectivity modification layers on the passivation layer, the one or more reflectivity modification layers comprising a plurality of alternating layers of high refractive-index material and low refractive-index material.

5. The laser device of claim 1, further comprising two to twenty alternating layers of high refractive-index material and low refractive-index material on the passivation layer of Al₂O₃ with a top-most layer being a high refractive-index material layer.

6. The laser device of claim 1, further comprising two to twenty alternating layers of high refractive-index material and low refractive-index material on the passivation layer of Al₂O₃ with a top-most layer being a low refractive-index material layer.

7. The laser device of claim 1, wherein the laser device is on a gallium and nitrogen containing epitaxial substrate.

8. The laser device of claim 1, wherein the laser device is bonded to a gallium-free substrate.

9. An apparatus comprising the laser device of claim 1, wherein the apparatus is a lighting apparatus, an automotive apparatus, a display apparatus, a LIDAR apparatus, or a materials processing apparatus.

10. A laser device, comprising:

a gallium-free substrate;

a gallium and nitrogen containing material having a total thickness of less than 10 μ

m overlying the gallium-free substrate, the gallium and nitrogen containing material having a cavity region characterized by a first end and a second end, the first end comprising a first facet, and the second end comprising a second facet; and

a passivation layer comprising a polycrystalline layer of Al₂O₃ directly contacting the first facet.

11. The laser device of claim 10, wherein the first facet comprises a plurality of etched striations along a direction substantially perpendicular to the gallium-free substrate.

12. The laser device of claim 10, wherein the first facet has a root mean square surface roughness Rq of about 10 μ

m or more.

13. The laser device of claim 10, wherein the first facet has a sidewall angle greater than 88 degrees to 92 degrees inclined relative to a surface normal of the gallium-free substrate.

14. The laser device of claim 10, further comprising an interface region between the gallium and nitrogen material and the gallium-free substrate, wherein the gallium-free substrate comprises at least one selected from the group consisting of Si, SiC, Al, AlN, diamond, and Cu.

15. The laser device of claim 10, wherein the first end comprises an etched surface substantially free of contaminants.