Growth of Semiinsulating GaAs Crystals by Vertical Gradient Freeze Technique

GaAs crystals having dislocation densities of 1–2 10³ cm^?2 were grown using VGF technique. In the grown crystals Si_Ga is the dominant donor and C_As the dominant acceptor. Theoretical and experimental investigations have shown the possibilities to influence on the silicon and carbon content in GaAs. Based on these results, semiinsulating properties in the crystals could be achieved reproducibly.