Reduction Mechanism of Dislocation Density in GaAs Films on Si Substrates

Significant reduction of dislocation densities in GaAs films grown on Si substrates have been demonstrated. High-quality GaAs films on Si with average etch-pit density on the order of 10 4 cm -2 have been obtained by combining the low-temperature growth technique and the atomic hydrogen irradiation. The reduction mechanism of dislocation density in GaAs on Si as well as possible growth kinetics have been discussed based on reflection high-energy electron diffraction (RHEED) and transmission electron microscope (TEM) observations. Most of the threading dislocations have annihilated in the low-temperature grown GaAs layers by forming closed loops. As a consequence of the dislocation density reduction, the electron mobilities of GaAs films on Si have been improved.