Vertical Gradient Freeze of Large Diameter, Low Effect Density Indium Phoside

The demand for larger diameter, low dislocation density InP substrates has traditionally been filled by highly doped LEC-grown material. We describe a superior process that produces uniformly high quality wafers from 111> seeded, 750 gram, 50 mm diameter single crystals. Typical dislocation levels are in the low 10(2)/cm(2) range, independent of doping level. The dislocations are shown to be uniformly distributed across a wafer and from seed to tail. The process features seeded growth in pyrolytic boron nitride crucibles under low axial and radial thermal gradients as well as independent stoichiometry control. The reduction of thermally generated strain eliminates the need for impurity of InP to achieve low defect levels.