Resistivity, Hall Mobility and Leakage Current Variations in Undoped Semi-Insulating GaAs Crystal Grown by LEC Method

The resistivity and Hall mobility (measured at 400 K) variations across undoped semi-insulating GaAs wafers obtained from the upper part of the LEC grown ingot have been measured and are compared with the dislocation density variation. It has been found that the resistivity is almost inversely proportional to the dislocation density and Hall mobility is proportional to the logarithm of the dislocation density. We have further measured the leakage current variation in comparison with the resistivity and dislocation density variation. Both the leakage current and resistivity show an M shaped variation across the wafers which have a W shaped dislocation density variation.