Method of forming a light-emitting device

• US 10,217,895 B2
• Filed: 06/22/2017
• Issued: 02/26/2019
• Est. Priority Date: 06/22/2017
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: Epistar Corporation (Ennostar, Inc.)
• Inventors: Chen, Chih-hao, Chou, Yi-Lun, Peng, Wei-Chih
• Primary Examiner(s): Schoenholtz, Joseph
• Application Number:
  US15/630,660
• Publication Number:
  US 20180374985A1
• Time in Patent Office: 614 Days
• Field of Search: None
• CPC Class Codes: H01L 2933/0016 relating to electrodes
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0075 comprising nitride compounds
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/10 with a light reflecting structure, e.g. semiconductor Bragg reflector

Abstract

The present disclosure provides a method of forming a light-emitting device comprising: providing a growth substrate having a front side and a rear side; forming a sacrificial layer on the front side of the growth substrate; forming a protective structure on the sacrificial layer; forming a light-emitting structure on the protective structure, wherein the light-emitting structure emits a first peak wavelength; providing a carrier; joining the carrier and the light-emitting structure; and transforming the sacrificial layer by irradiating a laser beam from the rear side to separate the growth substrate from the light-emitting structure, wherein the laser beam emits a second peak wavelength, and wherein the protective structure reflects the second peak wavelength away from the light-emitting structure.

Claims

1. A method of forming a light-emitting device comprising:

providing a growth substrate having a front side and a rear side;

forming a sacrificial layer on the front side of the growth substrate;

forming a protective structure on the sacrificial layer;

forming a light-emitting structure on the protective structure, wherein the light-emitting structure emits a first peak wavelength;

providing a carrier;

joining the carrier and the light-emitting structure; and

transforming the sacrificial layer by irradiating a laser beam from the rear side to separate the growth substrate from the light-emitting structure, wherein the laser beam emits a second peak wavelength, and wherein the protective structure reflects the second peak wavelength away from the light-emitting structure;

wherein the protective structure comprises a first portion and a second portion, wherein the method further comprises removing the first portion, and forming an electrode on the second portion.

2. The method of forming the light-emitting device of claim 1, further comprising forming a buffer structure between the growth substrate and the sacrificial layer.

3. The method of forming the light-emitting device of claim 1, wherein the protective structure comprises a DBR structure, the DBR structure comprises a reflectivity of 99% or more in the second peak wavelength.

4. The method of forming the light-emitting device of claim 3, wherein the DBR structure comprises semiconductor pairs, each of the semiconductor pairs comprises a first material layer having a first refractive index and a second material layer having a second refractive index, the first refractive index being greater than the second refractive index.

5. The method of forming the light-emitting device of claim 4, wherein the first material layer comprises Al_xGa_1-xN (0.6≤

x≤

0.8), and the second material layer comprises Al_yGa_1-yN (0.9≤

y≤

1).

6. The method of forming the light-emitting device of claim 4, wherein the first refractive index and the second refractive index are between 2.0 and 2.5.

7. The method of forming the light-emitting device of claim 4, wherein a number of the semiconductor pairs is between 10 and 40.

8. The method of forming the light-emitting device of claim 1, wherein the laser beam is irradiated by a KrF laser or an Nd:

YAG laser.

9. The method of forming the light-emitting device of claim 1, wherein the first peak wavelength and/or the second peak wavelength are between 210 and 400 nm, the first peak wavelength are different from the second peak wavelength.

10. The method of forming the light-emitting device of claim 2, wherein the buffer layer comprises Al_zGa_1-zN (0.6≤

z≤

1).

11. The method of forming the light-emitting device of claim 1, wherein the sacrificial layer comprises Al_wGa_1-wN (0≤

w≤

0.6).

12. The method of forming the light-emitting device of claim 1, wherein the substrate comprises AlN or sapphire.

13. The method of forming the light-emitting device of claim 1, wherein the sacrificial layer comprises an absorbance of 90% or more in the second peak wavelength.

14. The method of forming the light-emitting device of claim 2, wherein the buffer structure comprises a transmittance of 90% or more in the second peak wavelength.

15. The method of forming the light-emitting device of claim 1, wherein the growth substrate comprises a transmittance of 90% or more in the second peak wavelength.

16. The method of forming the light-emitting device of claim 1, further comprising providing a bonding layer between the carrier and the light-emitting structure, wherein the carrier and the bonding layer are conductive material.

17. The method of forming the light-emitting device of claim 1, further comprising forming a contact layer and a current blocking layer between the carrier and the light-emitting structure, wherein a material of the contact layer comprises Ag, and a material of the current blocking layer comprises SiO₂.