Method of manufacturing a semiconductor substrate having a cavity

• US 8,481,411 B2
• Filed: 02/10/2011
• Issued: 07/09/2013
• Est. Priority Date: 06/10/2009
• Status: Expired due to Fees

• Current Assignee: Seoul Viosys Co., Ltd. (Seoul Semiconductor Co., Ltd.)
• Original Assignee: Seoul Optodevice Company Limited (Seoul Semiconductor Co., Ltd.)
• Inventors: Sakai, Shiro
• Primary Examiner(s): PARENDO, KEVIN A
• Application Number:
  US12/929,712
• Publication Number:
  US 20110151647A1
• Time in Patent Office: 880 Days
• Field of Search: 438/46, 438/47, 438/478, 438/479, 438/481, 438/695, 438/700, 438/745, 438/746, 438/747, 257/E33.025, 257/E21.221
• US Class Current: 438/481
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 29/2003 Nitride compounds
• CPC Class Codes: H01L 33/0075 comprising nitride compounds

Abstract

The present invention provides a method of fabricating a semiconductor substrate, the method including forming a first semiconductor layer on a substrate, forming a metallic material layer on the first semiconductor layer, forming a second semiconductor layer on the first semiconductor layer and the metallic material layer, etching the substrate using a solution to remove the metallic material layer and a portion of the first semiconductor layer, and forming a cavity in the first semiconductor layer under where the metallic material layer was removed.

Claims

1. A method of fabricating a nitride semiconductor substrate, the method comprising:

forming a first nitride semiconductor layer on a substrate;

forming a metallic material layer on the first nitride semiconductor layer;

forming a second nitride semiconductor layer on the first nitride semiconductor layer and the metallic material layer, wherein a hole is formed in the metallic material layer and a first cavity is formed in the first nitride semiconductor layer under the metallic material layer during formation of the second nitride semiconductor layer;

etching the substrate using a solution to remove the metallic material layer and a portion of the first nitride semiconductor layer after forming the second nitride semiconductor layer;

forming a third nitride semiconductor layer on the second nitride semiconductor layer; and

forming a second cavity in the first nitride semiconductor layer under where the metallic material layer was removed.

2. The method of claim 1, wherein the solution comprises potassium hydroxide (KOH).

3. The method of claim 2, wherein the solution comprising KOH is heated to 200°

C.

4. The method of claim 1, wherein the solution comprises sodium hydroxide (NaOH).

5. The method of claim 4, wherein the solution comprising NaOH is heated to 300°

C.

6. The method of claim 1, wherein after the metallic material layer and the portion of the first nitride semiconductor layer is removed, the substrate comprises an irregular surface.

7. The method of claim 6, wherein the irregular surface comprises an unetched portion of the first nitride semiconductor layer and the second cavity.

8. The method of claim 1, wherein the surface of the third nitride semiconductor layer is formed to be substantially flat.

9. A method of fabricating a nitride semiconductor substrate, the method comprising:

forming a first nitride semiconductor layer on a substrate;

forming a metallic material layer on the first nitride semiconductor layer;

forming a second nitride semiconductor layer on the first nitride semiconductor layer and the metallic material layer, wherein a hole is formed in the metallic material layer and a first cavity is formed in the first nitride semiconductor layer under the metallic material layer during formation of the second nitride semiconductor layer;

dipping the substrate in a solution to remove the metallic material layer and a portion of the first nitride semiconductor layer after forming the second nitride semiconductor layer;

forming a third nitride semiconductor layer on the second nitride semiconductor layer; and

forming a second cavity in the first nitride semiconductor layer under where the metallic material layer was removed.

10. The method of claim 9, wherein the solution comprises hydrogen fluoride (HF).

11. The method of claim 10, wherein the solution comprises 50% HF.

12. The method of claim 9, wherein after the metallic material layer and the portion of the first nitride semiconductor layer is removed, the substrate comprises an irregular surface.

13. The method of claim 12, wherein the irregular surface comprises an unetched portion of the first nitride semiconductor layer and the second cavity.

14. The method of claim 9, wherein the surface of the third nitride semiconductor layer is formed to be substantially flat.