Inhomogeneity of Resistivity in In-Doped Dislocation-Free Semi-Insulating LEC GaAs

Abstract

In-doped dislocation-free semi-insulating GaAs crystals were prepared from various melt compositions and measurement of resistivity distributions and infrared absorption at 1 µm were carried out. Inhomogeneity of resistivity, both along the radial and longitudinal directions, was observed even in some dislocation-free crystals. This inhomogeneity strongly depends on melt composition, and is mainly due to non-uniform distribution of stoichiometry-related defects revealed by infrared absorption measurement.