Patent ID: 7378351

Claim:
A method of manufacturing a nitride semiconductor device using a GaN substrate, the method comprising a step of forming a nitride semiconductor layer on a GaN substrate main surface; a step of polishing a back surface of the GaN substrate formed with the above-mentioned nitride semiconductor layer; a step of dry etching the back surface of the GaN substrate subjected to the above-mentioned polishing by using a gas mixture of chlorine and oxygen; a step of forming an n-type electrode on the back surface of the GaN substrate subjected to the above-mentioned dry etching; and after the step of forming an n-type electrode on the back surface of the GaN substrate, a heat treatment step at a temperature of 350° C. to 390° C. in a gas mixture of oxygen and an inert gas containing 5 to 15% oxygen in partial pressure percentage to form an ohmic contact between the n-type electrode and the GaN substrate.