Novel for technique a surface emitting laser diode with a metal reflector

• US 20030040133A1
• Filed: 08/24/2001
• Published: 02/27/2003
• Est. Priority Date: 08/24/2001
• Status: Active Grant

• Current Assignee: Telecommunications Laboratories Chunghwa Telecom Company Limited
• Original Assignee: Telecommunications Laboratories Chunghwa Telecom Company Limited
• Inventors: Horng, Ray-Hua, Peng, Wei-Chih, Wu, Dong-Sing, Ho, Wen-Jeng, Huang, Ying-Shun
• Granted Patent: US 6,656,756 B2
• Time in Patent Office: Days
• US Class Current: 438/22
• CPC Class Codes: H01S 5/0217 Removal of the substrate
• CPC Class Codes: H01S 5/18375 based on metal reflectors
• CPC Class Codes: H01S 5/1838 Reflector bonded by wafer fusion or by an intermediate compound

Abstract

The present invention is related to a method for fabricating a surface-emitting laser diode with a metal reflector. It is mainly the use of a combination of a metal reflector and wafer bonding technology to replace the traditional epiwafer process or high-temperature high-pressure wafer bonding technology in fabricating VCSEL Bragg Reflector. The metal reflector has high reflectance with its material selected to form ohmic contact with VCSEL material. Besides, the substrate for the metal reflector can be selected for cheap price and good heat dissipation. Further advantages include simple process, low production cost and good VCSEL characteristic etc.

Claims

1. A method for fabricating a surface-emitting laser diode with a metal reflector, which is made of a substrate that has a metal reflector structure and a substrate that has a epiwafer film of surface-emitting laser structure by wafer bonding technology and removal technology for epiwafer film substrate.

2. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 1, wherein the wafer bonding technology includes the following procedures:

(1) drying Si or GaAs by blowing N₂, placing it in acetone, applying ultrasonic vibration for about 10 minutes, and rinsing it by deionized water;

(2) drying VCSEL by blowing N₂, placing it in acetone, applying ultrasonic vibration for about 10 minutes, and rinsing it by deionized water;

(3) coating the above two with Au/AuBe;

(4) drying it by blowing N₂, bonding the two wafers face to face;

(5) placing the wafer pair in polishing fixture for heat treatment; and

(6) after heat treatment being completed, removing InP Substrate.

3. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 1, wherein the substrate for the metal reflector structure can be Si, GaAs, InP, GaP, Sapphire and Corning glass.

4. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 3, wherein the substrate can be used for heat dissipation or epiwafer mechanical support.

5. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 1, wherein the metal of metal reflector structure can be Au, AuBe, AuZn, AuGeNi, AuGe, Ni, Pt, Ti, TiN, Ta, TaN and Pd in layer of a single kind of metal or in multiple layers of metals.

6. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 5, wherein the metal structure can be used as reflector, ohmic contact, bonding layer for wafer pairs.

7. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 1, wherein the metal of claim 5 can be coated on the substrate that has a metal reflector of claim 3 by thermal evaporation deposition, e-beam evaporation deposition, sputtering deposition or combination of the above methods.

8. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 1, wherein the substrate for the epiwafer film of surface-emitting laser structure can be GaAs, InP etc.

9. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 1, wherein the surface-emitting laser diode can have laser with wavelengths of 850, 1300 and 1500 nm. The laser diode can be produced by metal organic chemical vapor deposition or molecular beam epitaxial growth.

10. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 8, wherein the laser structure must have a etch stop layer, which is mainly etching solution resistant material, InxGa1-xAsyP1-y material or Alx-1Ga1-xAs.

11. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 1, wherein the wafer bonding technology can be thermal pressing, pneumatic pressing or direct bonding.

12. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 1, wherein the substrate removal technology for epiwafer film can be polishing, wet chemical etching, dry etching or combinations of the above.

13. The method for fabricating a surface-emitting laser diode with a metal reflector of claim 12, wherein if the substrate removal technology for epiwafer film is wet chemical etching, the etching solution is composed of hydrochloric acid or hydrochloric acid and phosphoric acid or ammonia water and hydrogen peroxide.