Process for etching gallium nitride compound based semiconductors

• US 6,605,548 B1
• Filed: 05/30/2000
• Issued: 08/12/2003
• Est. Priority Date: 06/01/1999
• Status: Expired due to Term

• Current Assignee: National Research Council Canada
• Original Assignee: National Research Council Canada
• Inventors: Bardwell, Jennifer
• Primary Examiner(s): Utech, Benjamin L.
• Assistant Examiner(s): DEO, DUY VU NGUYEN
• Application Number:
  US09/579,497
• Time in Patent Office: 1,169 Days
• Field of Search: 438/745, 438/752, 216/2, 216/65, 216/67
• US Class Current: 438/745
• CPC Class Codes: H01L 21/30617 Anisotropic liquid etching

Abstract

A method for wet etching a gallium nitride compound-based semiconductor is disclosed. The method uses an aqueous solution containing an oxidizing agent such as peroxydisulfate ions. The sample and solution are irradiated with visible or ultraviolet light in order to promote the etching.

Claims

1. A method for etching a gallium nitride compound-based semiconductor, comprising:

applying to the semiconductor an aqueous solution containing an oxidizing agent, the solution and said oxidizing agent in combination capable of dissolving gallium oxide and consuming electrons generated during etching, wherein the oxidizing agent comprises peroxydisulfate ions, the solution comprising hydroxide or hydrogen ions.

2. The method according to claim 1 wherein said solution and said semiconductor are irradiated with light of a wavelength selected from the visible and ultraviolet.

3. The method according to claim 2, wherein the semiconductor is irradiated with light of a frequency above the band gap of the semiconductor.

4. The method according to claim 1, wherein both the sample and solution are irradiated with light of wavelength shorter than 260 nm such that free radicals are produced by the photochemical reaction of the peroxydisulfate ions.

5. The method according to claim 2, wherein the aqueous solution is purged with an inert gas to remove dissolved oxygen before any light illumination is provided, and throughout the etching process.

6. The method according to claim 1, wherein the semiconductor is partially masked with a metal that is essentially resistant to etching under the gallium nitride compound-based semiconductors etching conditions.

7. The method according to claim 1, wherein the semiconductor is partially masked with a non-metallic material that is essentially chemically inert under the gallium nitride compound-based semiconductor etching conditions.

8. The method according to claim 1, wherein the gallium nitride compound-based semiconductor includes at least one of Al_xGa₁₋

xN, In<sub>1−

y</sub>Ga_yN and GaN semiconductors.