Methods for cleaving facets in III-V nitrides grown on c-face sapphire substrates

• US 6,379,985 B1
• Filed: 08/01/2001
• Issued: 04/30/2002
• Est. Priority Date: 08/01/2001
• Status: Expired due to Term

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Cervantes, Tanya J., Romano, Linda T., Kneissl, Michael A.
• Primary Examiner(s): Mulpuri, Savitri
• Application Number:
  US09/682,181
• Time in Patent Office: 272 Days
• Field of Search: 438/33, 438/478, 438/460, 438/462, 438/483, 438/973, 438/974, 438/975, 438/977, 257/13, 257/103, 257/96, 372/45, 372/46
• US Class Current: 438/33
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 33/007 comprising nitride compounds
• CPC Class Codes: H01L 33/0095 Post-treatment of devices, e.g. annealing, recrystallisation or short-circuit elimination
• CPC Class Codes: H01S 5/0202 Cleaving
• CPC Class Codes: H01S 5/0213 Sapphire, quartz or diamond based substrates
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP

Abstract

Methods for cleaving semiconductor structures formed on c-face sapphire substrates are disclosed. An exemplary method includes forming at least one III-V nitride layer on the top c-face of a c-face sapphire substrate. A line of weakness is formed on the bottom c-face of the c-face sapphire substrate in the a-plane direction of the c-face sapphire substrate. A force is applied to the bottom c-face to cleave the c-face sapphire substrate along the line of weakness in the a-plane direction, and to form a cleaved facet along an m-plane of each III-V nitride layer. The III-V nitride layers can be included in laser diodes and other light-emitting devices.

Claims

1. A method for cleaving at least one III-V nitride layer of a semiconductor structure formed on a c-face sapphire substrate, comprising:

forming a semiconductor structure comprising at least one III-V nitride layer on a top c-face of a c-face sapphire substrate, the c-face sapphire substrate including a bottom c-face and an edge between the top c-face and bottom c-face;

forming a line of weakness on the bottom c-face of the c-face sapphire substrate along at least substantially the length of a line that (i) extends in an a-plane direction of the c-face sapphire substrate and (ii) extends from one portion of the edge of the c-face sapphire substrate to another portion of the edge; and

applying a force to the bottom c-face of the c-face sapphire substrate to cleave the c-face sapphire substrate along the line of weakness in the a-plane direction and to form a cleaved facet along an m-plane of the at least one III-V nitride layer.

2. The method of claim 1, wherein the cleaved facet formed in the at least one III-V nitride layer is substantially perpendicular to the top c-face of the c-face sapphire substrate.

3. The method of claim 1, wherein the c-face sapphire substrate has a thickness of less than about 250 microns.

4. The method of claim 1, wherein the c-face sapphire substrate has a generally circular configuration and a diameter, and forming the line of weakness comprises weakening the bottom c-face of the c-face sapphire substrate along substantially the entire diameter in the a-plane direction of the c-face sapphire substrate.

5. The method of claim 1, wherein the line of weakness if formed by scribing the bottom c-face of the c-face sapphire substrate in the a-plane direction of the c-face sapphire substrate.

6. The method of claim 1, wherein the line of weakness is formed by ablating the bottom c-face of the c-face sapphire substrate in the a-plane direction of the c-face sapphire substrate by laser ablation.

7. The method of claim 1, wherein the line of weakness is formed by etching the bottom c-face of the c-face sapphire substrate in the a-plane direction of the c-face sapphire substrate.

8. The method of claim 1, wherein the line of weakness is formed along the entire length of the line on the bottom c-face of the c-face sapphire substrate in the a-plane direction of the c-face sapphire substrate.

9. The method of claim 1, wherein the cleaved facet of the at least one III-V nitride layer has an rms roughness of less than about 200 Å

.

10. The method of claim 1, wherein the at least one semiconductor structure comprises at least one diode laser.

11. The method of claim 1, wherein the at least one semiconductor structure comprises at least one light-emitting diode.