Method of oxidizing nitride material enhanced by illumination with UV light at room temperature

• US 6,190,508 B1
• Filed: 04/07/1999
• Issued: 02/20/2001
• Est. Priority Date: 04/07/1998
• Status: Expired due to Fees

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Huang, Chao-Nien, Hsu, Yi-Chien, Chen, Chin-Yuan, Peng, Lung-Han, Ho, Jin-Kuo
• Primary Examiner(s): Gorgos, Kathryn
• Assistant Examiner(s): TRAN, THAO T
• Application Number:
  US09/287,326
• Time in Patent Office: 685 Days
• Field of Search: 204/157.46, 204/157.5, 204/157.4, 204/157.41
• US Class Current: 204/157.46
• CPC Class Codes: C01B 13/324 by solid combustion synthesis
• CPC Class Codes: C01G 1/02 Oxides
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram

Abstract

A method of forming oxide from nitride, in which the oxidation is enhanced by illuminating the nitride material with UV light. This method produces a rapid growth of oxide and allows for the monitoring of the oxide thickness in situ. The method comprises the steps of (i) placing the nitride material on an illuminating holder; (ii) dipping the nitride material and the illuminating holder in an electrolyte; and (iii) illuminating the nitride material with a light having an energy larger than the energy gap of the nitride material. The nitride material can be connected to a conductive electrode located in the electrolyte via a galvanometer to monitor a photo current generated by the oxidation of the nitride material so as to monitor the thickness of the oxide formed on the nitride material in situ. A metal coating can be coated on the nitride material to define the oxide forming region. The pH value of the electrolyte is in a range of approximately 3 to 10, and is preferably about 3.5.

Claims

1. A method of oxidizing a nitride material at room temperature comprising the steps of:

(i) placing the nitride material on an illuminating holder;

(ii) dipping the nitride material and the illuminating holder in an electrolyte having a pH value approximately ranged from 3 to 10; and

(iii) illuminating the nitride material with a light having an energy larger than the energy gap of the nitride material.

2. A method of oxidizing a nitride material as claimed in claim 1 further comprising a step of coating a metal coating on the nitride material to define a region of forming oxide prior to step (i).

3. A method of oxidizing a nitride material as claimed in claim 1 further comprising a step of connecting the nitride material to a conductive electrode located in the electrolyte via a galvanometer after step (iii) to monitor a photo current generated by oxidation of the nitride material so as to monitor a thickness of the oxide formed on the nitride material in situ.

4. A method of oxidizing a nitride material as claimed in claim 1 wherein the nitride material is gallium nitride.

5. A method of oxidizing a nitride material as claimed in claim 1 wherein the light illuminating the nitride material is UV light.

6. A method of oxidizing a nitride material as claimed in claim 2 wherein the metal coating is dual-layer including an inner layer and an outer layer, in which a work function of the outer layer is larger than that of the inner layer.

7. A method of oxidizing a nitride material as claimed in claim 1 wherein the electrolyte is one of KOH, H₂O₂, H₂SO₄ or H₃PO₄.

8. A method of oxidizing a nitride material as claimed in claim 1 wherein the pH value is around 3.5.

9. A method of oxidizing a nitride material as claimed in claim 5 wherein the light source is one of a 308-nm XeCl excimer laser, a 248-nm KrF excimer laser, a 193-nm ArF excimer laser, a 157-nm F₂ excimer laser, a N₂ molecular laser, He—

Cd molecular laser, a quarter-wavelength YAG laser, a deuterium lamp or a xenon lamp.

10. A method of oxidizing a nitride material as claimed in claim 6 wherein the outer layer of the dual-layer metal coating is one of Re, Pt, Ru, Rh, Pd, Au, Ir, Ni or a composition thereof.

11. A method of oxidizing a nitride material as claimed in claim 6 wherein the inner layer of dual-layer metal coating is one of Ti, V, Cr, Zr, Mo, Hf, Ta, W or a composition thereof.