Selective growth process for group III-nitride-based semiconductors

• US 6,265,322 B1
• Filed: 09/21/1999
• Issued: 07/24/2001
• Est. Priority Date: 09/21/1999
• Status: Expired due to Term

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Agere Systems Guardian Corp. (Broadcom, Inc.)
• Inventors: Anselm, Klaus Alexander, Cho, Alfred Yi, Chu, Sung-Nee George
• Primary Examiner(s): Utech, Benjamin L.
• Assistant Examiner(s): DEO, DUY VU NGUYEN
• Application Number:
  US09/399,655
• Time in Patent Office: 672 Days
• Field of Search: 117/88, 117/89, 117/92, 117/97, 117/103, 117/108, 117/952, 438/47, 438/94, 438/745, 438/757, 372/45, 257/94, 257/103
• US Class Current: 438/745
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02639 Preparation of substrate for selective deposition
• CPC Class Codes: H01L 21/3185 of siliconnitrides

Abstract

A method of forming selected Group III-nitride regions uses a masking layer to cause differential growth between single crystal Group III-nitride material and polycrystalline Group III-nitride material. The epitaxial process is chosen to provide vertical growth so as to allow for replication of the mask edges at the defined limits for the selected regions. By using an etchant that is selective between polycrystalline and single crystal Group III-nitride material, the polycrystalline material (that grew over the mask layer) can be removed, leaving only the single crystal Group III-nitride (that grew over the exposed substrate material).

Claims

1. A method for selectively forming Group III-nitrides on selected substrate areas, the method comprising the steps of:

a) providing a substrate of material compatible with the growth of a Group-III-nitride layer;

b) masking said substrate with a layer of masking material so as to leave exposed those areas of said substrate selected for growth of a Group III-nitride layer;

c) epitaxially growing a Group III-nitride layer over the structure formed in step b) using an epitaxial process that yields vertical growth, the epitaxial material grown over the masking layer being polycrystalline with both Group III-polar crystal surfaces and N-polar crystal surfaces and the epitaxial material grown over the substrate being single crystal with Group III-polar crystal surfaces;

d) etching the epitaxial Group III-nitride material with an etchant that selectively removes the N-polar crystal surfaces of the polycrystalline material with respect to the Group III-polar single crystal material; and

e) removing the masking layer of step b).

2. The method as defined in claim 1 wherein the Group III-nitride comprises GaN.

3. The method as defined in claim 1 wherein in performing step a), the substrate material is chosen from the group consisting of Al₂O₃, SiC and GaN.

4. The method as defined in claim 3 wherein in performing step a), the substrate material comprises GaN.

5. The method as defined in claim 1 wherein in performing step a), a planar substrate is provided.

6. The method as defined in claim 1 wherein in performing step a), a non-planar substrate is provided.

7. The method as defined in claim 1 wherein in performing step b), silicon dioxide is used as the masking material.

8. The method as defined in claim 1 wherein in performing step c), a reactive nitrogen plasma process is used to generate the vertical epitaxial growth.

9. The method as defined in claim 1 wherein in performing step d), potassium hydroxide is used as the etchant.

10. The method as defined in claim 1 wherein in performing step e), hydrofluoric acid is used to remove the masking layer.