UV LIGHT EMITTING DEVICES AND SYSTEMS AND METHODS FOR PRODUCTION

• US 20170317229A1
• Filed: 07/19/2017
• Published: 11/02/2017
• Est. Priority Date: 07/23/2014
• Status: Active Grant

• Current Assignee: Rayvio Corporation
• Original Assignee: Rayvio Corporation
• Inventors: LIAO, Yitao, WALKER, Robert, COLLINS, Doug
• Granted Patent: US 10,439,099 B2
• Time in Patent Office: Days
• CPC Class Codes: C23C 14/0036 Reactive sputtering
• CPC Class Codes: C23C 14/0617 AIII BV compounds, where A is Al, Ga, In or Tl and B is N, P, As, Sb or Bi
• CPC Class Codes: C23C 14/0641 Nitrides C23C14/0617 takes precedence
• CPC Class Codes: C23C 14/568 Transferring the substrates through a series of coating stations C23C14/562 takes precedence
• CPC Class Codes: C23C 16/18 from metallo-organic compounds
• CPC Class Codes: C23C 16/303 Nitrides
• CPC Class Codes: C23C 16/481 by radiant heating of the substrate
• CPC Class Codes: C23C 16/54 Apparatus specially adapted for continuous coating
• CPC Class Codes: H01L 21/0243 Surface structure
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02505 consisting of more than two layers
• 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 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/0025 comprising only AIIIBV compounds
• CPC Class Codes: H01L 33/0062 for devices with an active region comprising only III-V compounds
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• 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 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/18 : within the light emitting region
• CPC Class Codes: H01L 33/32 : containing nitrogen

Abstract

A method of fabricating an ultraviolet (UV) light emitting device includes receiving a UV transmissive substrate, forming a first UV transmissive layer comprising aluminum nitride upon the UV transmissive substrate using a first deposition technique at a temperature less than about 800 degrees Celsius or greater than about 1200 degrees Celsius, forming a second UV transmissive layer comprising aluminum nitride upon the first UV transmissive layer comprising aluminum nitride using a second deposition technique that is different from the first deposition technique, at a temperature within a range of about 800 degrees Celsius to about 1200 degrees Celsius, forming an n-type layer comprising aluminum gallium nitride layer upon the second UV transmissive layer, forming one or more quantum well structures comprising aluminum gallium nitride upon the n-type layer, and forming a p-type nitride layer upon the one or more quantum well structures.

Claims

1. An ultraviolet (UV) light emitting device comprising:

a UV transmissive substrate;

a first UV transmissive layer comprising aluminum nitride disposed upon the first UV transmissive layer, wherein the first UV transmissive layer is characterized by a first defect density;

a second UV transmissive layer comprising aluminum nitride disposed upon the first UV transmissive layer, wherein the second UV transmissive layer is characterized by a second defect density, and wherein the first defect density is higher than the second defect density;

an n-type layer comprising aluminum gallium nitride disposed upon the UV transmissive layer;

one or more light emitting structures disposed upon the n-type layer; and

a p-type layer comprising nitride material disposed upon the one or more light emitting structures.

2. The UV device of claim 1 wherein the first UV transmissive layer and the second UV transmissive layer together has a thickness within a range within about 100 nm to about 3 microns.

3. The UV device of claim 1 wherein the UV transmissive layer has a thickness within a range within about 3 microns to about 10 microns.

4. The UV device of claim 1 wherein the UV transmissive layer has transmissivity in the UV wavelength range within a transmissivity range of about 50% to about 99%.

5. The UV device of claim 1

wherein the first UV transmissive layer comprises polycrystalline aluminum nitride;

and

wherein the second UV transmissive layer comprises single crystal aluminum nitride.

6. The UV device of claim 1 wherein the UV transmissive substrate comprises a plurality of patterns that scatter strongly with short wavelength UV light.

8. The UV device of claim 1 wherein the one or more light emitting structures comprise structures selected from a group consisting of:

quantum structures, and quantum wells.

9. The UV device of claim 1, wherein the UV transmissive substrate is selected from a group consisting of:

quartz, sapphire, and free standing single crystal aluminum nitride.

10. The UV device of claim 1, wherein the first defect density is lower than 1e10 cm-2.

11. An ultraviolet (UV) light emitting device comprising:

a UV transmissive substrate;

a UV transmissive layer disposed upon the UV transmissive substrate, the UV transmissive layer comprising;

a first UV transmissive layer comprising aluminum and nitrogen disposed upon the first UV transmissive layer, wherein the first UV transmissive layer is characterized by a first quality;

a second UV transmissive layer comprising aluminum and nitrogen disposed upon the first UV transmissive layer, wherein the second UV transmissive layer is characterized by a second quality, and wherein the first quality is lower than the second quality; and

a UV light emitting structure disposed upon the UV transmissive layer, the UV light emitting layer structure comprising;

an n-type layer comprising aluminum gallium nitride disposed upon the UV transmissive layer;

one or more light emitting structures disposed upon the n-type layer; and

a p-type layer comprising nitride material disposed upon the one or more light emitting structures.

7. The UV device of claim 11 wherein the plurality of patterns comprises geometric features having a lateral spacing within a range of 0.1 to 5 microns.

12. The UV device of claim 11 wherein the UV transmissive layer has a thickness within a range within about 10 nm to about 3 microns.

13. The UV device of claim 11 wherein the UV transmissive layer has a thickness within a range within about 3 microns to about 10 microns.

14. The UV device of claim 11 wherein the UV transmissive layer has transmissivity in the UV wavelength range within a transmissivity range of about 50% to about 99%.

15. The UV device of claim 11

wherein the first UV transmissive layer comprises polycrystalline aluminum nitride;

and

wherein the second UV transmissive layer comprises single crystal aluminum nitride.

16. The UV device of claim 11

wherein the first quality comprises a first defect density;

wherein the second quality comprise a second defect density; and

wherein the second defect density is lower than the first defect density.

17. The UV device of claim 16, wherein the first defect density is lower than 1e10 cm-2.

18. The UV device of claim 11 wherein the UV transmissive substrate comprises a plurality of patterns that scatter strongly with short wavelength UV light.

19. The UV device of claim 11 wherein the one or more light emitting structures comprise structures selected from a group consisting of:

quantum structures, and quantum wells.

20. The UV device of claim 11, wherein UV transmissive substrate is selected from a group consisting of:

quartz, sapphire, and free standing single crystal aluminum nitride.