Inhomogeneity in Semi-Insulating GaAs Revealed by Scanning Leakage Current Measurements

Abstract

Inhomogeneity in semi-insulating (SI)-GaAs has been examined by scanning leakage current ( I L ) measurements. The observed leakage current exhibits broad intensity variation accompanying short period sharp fluctuation along both radial and pulling directions. The undoped SI-GaAs generally shows marked inhomogeneity of the leakage current compared with the Cr-doped GaAs. The broad I L intensity variation along the radial direction is correlated with dislocation distribution. Thermal annealing at 850°C for 1 hour in H 2 significantly smooths out the inhomogeneity.