Vapor deposition of single crystal gallium nitride

A method of manufacturing single crystals consisting essentially of gallium nitride comprising introducing gallium chloride and ammonia into an upstream portion of an open elongated reactor causing said gallium chloride and ammonia to react, said gallium chloride being produced in the reactor by the action of a first supply of hydrogen chloride on a quantity of liquid gallium contained in a bulge in said reactor, in the vapor phase while in the presence of a carrier gas depositing the resultant gallium nitride on a substrate located in the reactor downstream from the point of introduction of said gallium chloride said ammonia and most of the carrier gas being introduced into a first upstream end of said reactor thereby creating an ammonia containing atmosphere which flows from said upstream end to a second downstream end of said reactor removing residual gases from the proximity of said downstream end, directing said gallium chloride produced to flow in said reactor in a direction parallel to the flow of said ammonia containing atmosphere along a route to the deposition zone separate from that of the ammonia containing atmosphere and the rate of flow of said gallium chloride containing stream is between half and five times the rate of flow of said ammonia containing atmosphere, while introducing into said reactor a second supply of free hydrogen chloride in an amount such that the partial pressure of said hydrogen chloride in the reaction and deposition zones in said reactor is from 2 to 50% of the total pressure in said reactor, said carrier gas being free of hydrogen, the total pressure within the reactor being about the order of atmospheric pressure, the partial pressure of the ammonia being more than 0.150 atmospheres, the partial pressure of the gallium chloride being less than 0.05 atmospheres, the partial pressure of the hydrogen chloride being between 0.02 and 0.4 atmospheres and the temperatures in the reaction and deposition zones being from 720.degree. C. to 1100.degree. C.