Improvement in the quality, size and cost of indium phosphide (InP) single crystals is necessary in order to realize the high performance benefits of InP-based microwave and millimeter wave monolithic integrated circuit technology. To meet this need, the project will implement a novel modification to the Vertical Gradient Freeze (VGF) crystal growth method. The modification will enhance the VGF technique by enabling active control to be exerted over the defect-inducing thermal stresses that degrade the quality of InP crystals. The VGF technique is well suited to economical, large-scale production as it combines simplicity of design with low operator attention requirements. The physical processes of VGF are well understood which forms a solid foundation for the practical engineering approach. If the approach proves feasible, development of sources for the desired InP material will be straightforward.