LIGHT-EMITTING DEVICE

• US 20170047478A1
• Filed: 10/26/2016
• Published: 02/16/2017
• Est. Priority Date: 11/21/2014
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: LU, Chih-Chiang, LIN, Yi-Chieh, LIAO, Wen-Luh, CHEN, Shou-Lung, HUANG, Chien-Fu
• Granted Patent: US 10,236,411 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 27/15 including semiconductor components having potential barriers, specially adapted for light emission
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 2933/0025 relating to coatings
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 33/005 Processes
• CPC Class Codes: H01L 33/0062 for devices with an active region comprising only III-V compounds
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H04L 41/0668 by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure
• CPC Class Codes: H04L 41/0695 the faulty arrangement being the maintenance, administration or management system
• CPC Class Codes: H04L 41/0816 the condition being an adaptation, e.g. in response to network events
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering

Abstract

A light-emitting device comprises a first light-emitting semiconductor stack comprising a first active layer; a second light-emitting semiconductor stack below the first light-emitting semiconductor stack, wherein the second light-emitting semiconductor stack comprises a second active layer; a wavelength filter between the first light-emitting semiconductor stack and the second light-emitting semiconductor stack; a protecting layer between the wavelength filter and the second light-emitting semiconductor stack; and wherein the first light-emitting semiconductor stack further comprises a first semiconductor layer and a second semiconductor layer sandwiching the first active layer, the second light-emitting semiconductor stack further comprises a third semiconductor layer and a fourth semiconductor layer sandwiching the second active layer, wherein the second semiconductor layer has a first band gap, the third semiconductor layer has a second band gap, and the protecting layer has a third band gap between the first band gap and the second band gap.

Claims

1. A light-emitting device, comprising:

a first light-emitting semiconductor stack comprising a first active layer;

a second light-emitting semiconductor stack below the first light-emitting semiconductor stack, wherein the second light-emitting semiconductor stack comprises a second active layer;

a wavelength filter between the first light-emitting semiconductor stack and the second light-emitting semiconductor stack;

a protecting layer between the wavelength filter and the second light-emitting semiconductor stack;

wherein the first active layer emits a first radiation of a first dominant wavelength, and the second active layer emits a second radiation of a second dominant wavelength longer than the first dominant wavelength; and

wherein the first light-emitting semiconductor stack further comprises a first semiconductor layer and a second semiconductor layer sandwiching the first active layer, the second light-emitting semiconductor stack further comprises a third semiconductor layer and a fourth semiconductor layer sandwiching the second active layer, wherein the second semiconductor layer has a first band gap, the third semiconductor layer has a second band gap, and the protecting layer has a third band gap between the first band gap and the second band gap.

2. The light-emitting device according to claim 1, further comprising a first contact layer on the first light-emitting semiconductor stack, wherein the first contact layer and the wavelength filter are of the same conductivity type.

3. The light-emitting device according to claim 2, further comprising an etching stop layer between the first contact layer and the protecting layer.

4. The light-emitting device according to claim 3, wherein the etching stop layer has a thickness between 50 nm and 100 nm both inclusive.

5. The light-emitting device according to claim 3, wherein the etching stop layer and the first contact layer are of the same conductivity type.

6. The light-emitting device according to claim 1, wherein the protecting layer has a thickness less than 1 um.

7. The light-emitting device according to claim 6, wherein the protecting layer has a doping concentration between 1×

10¹⁷/cm³ and 1×

10¹⁹/cm³.

8. The light-emitting device according to claim 1, wherein the third semiconductor layer and the second semiconductor layer are of the same conductivity type.

9. The light-emitting device according to claim 1, further comprising a first current spreading layer between the protecting layer and the second light-emitting semiconductor stack.

10. The light-emitting device according to claim 9, further comprising an etching stop layer between the first current spreading layer and the second light-emitting semiconductor stack.

11. The light-emitting device according to claim 1, further comprising an etching stop layer between the protecting layer and the second light-emitting semiconductor stack.

12. The light-emitting device according to claim 1, wherein the wavelength filter has a higher reflectivity to the first dominant wavelength than that to the second dominant wavelength.

13. The light-emitting device according to claim 1, wherein the protecting layer has a thickness between 50 nm and 100 nm both inclusive.

14. The light-emitting device according to claim 1, wherein the protecting layer has a doping concentration between 1×

10¹⁷/cm³ and 1×

10¹⁹/cm³ both inclusive.

15. The light-emitting device according to claim 1, wherein the protecting layer comprises InGaP and is substantially devoid of Al.

16. A light-emitting device, comprising:

a first light-emitting semiconductor stack comprising a first active layer;

a second light-emitting semiconductor stack below the first light-emitting semiconductor stack, wherein the second light-emitting semiconductor stack comprises a second active layer;

a wavelength filter between the first light-emitting semiconductor stack and the second light-emitting semiconductor stack;

an etching stop layer between the wavelength filter and the second light-emitting semiconductor stack, wherein the etching stop layer has a first transverse width;

a first contact layer between the etching stop layer and the second light-emitting semiconductor stack, wherein the first contact layer has a second transverse width;

wherein the first active layer emits a first radiation of a first dominant wavelength and the second active layer emits a second radiation of a second dominant wavelength longer than the first dominant wavelength; and

wherein the second transverse width is greater than the first transverse width.

17. The light-emitting device according to claim 16, wherein the etching stop layer has a thickness between 50 nm and 100 nm both inclusive.

18. The light-emitting device according to claim 16, wherein the etching stop layer and the first contact layer are of the same conductivity type.

19. The light-emitting device according to claim 16, wherein the etching stop layer has a doping concentration between 1×

10¹⁷/cm³ and 1×

10¹⁹/cm³ both inclusive.

20. The light-emitting device according to claim 16, wherein the wavelength filter has a third transverse width less than the second transverse width.