The production of high quality, III-V compound semiconductor crystals

A new technique, called the Gault process, has been developed at AT&T Engineering Research Center for growing large, single crystals of gallium arsenide, gallium phosphide, and indium phosphide. It can produce seeded, 50-mm diameter crystals that have lower dislocation densities and more uniform properties at all levels of doping than crystals grown by existing methods. In this paper, we describe the Gault process, which is based on the vertical gradient freeze method. Its features include seeded crystal growth in a boron nitride crucible, with much lower axial and radial thermal gradients than the conventional, liquid-encapsulated Czochralski process. We show that establishing an appropriate phosphorus or arsenic vapor pressure over the melt is an effective method of stoichiometry control. Also, a nearly planar liquid-solid interface has positive implications for radial uniformity and the occurrence of twinning and polycrystalline nucleation.