Patent ID: 8349076

Claim:
A method of fabricating a freestanding gallium nitride (GaN) substrate, the method comprising: preparing a GaN substrate layer within a reactor; supplying HCl and NH 3 gases and N 2 carrier gas into the reactor and using the HCl and NH 3 gases to treat a surface of the GaN substrate layer and to form a porous GaN layer in the GaN substrate layer; forming a GaN crystal growth layer directly on the porous GaN layer; and naturally in the reactor, cooling to room temperature the GaN substrate layer on which the porous GaN layer and the GaN crystal growth layer are formed, thereby separating the GaN crystal growth layer from the GaN substrate layer and GaN porous layer to provide the freestanding GaN substrate, wherein the preparing of the GaN substrate layer comprises loading a semiconductor substrate into the reactor and forming the GaN substrate layer on the semiconductor substrate.