A vapor transport growth process for bulk growth of high quality gallium
nitride for semiconductor applications is disclosed. The method includes
the steps of heating a gallium nitride source material, a substrate
suitable for epitaxial growth of GaN thereon, ammonia, a transporting
agent that will react with GaN to form gallium-containing compositions,
and a carrier gas to a temperature sufficient for the transporting agent
to form volatile Ga-containing compositions from the gallium nitride
source material. The method is characterized by maintaining the
temperature of the substrate sufficiently lower than the temperature of
the source material to encourage the volatile gallium-containing
compositions to preferentially form GaN on the substrate.