Dislocation reduction by impurity diffusion in epitaxial GaAs grown on Si

Abstract
Data are presented showing that low-temperature Zn diffusion (680 °C) is effective in reducing the dislocation density in epitaxial GaAs grown on Si. The GaAs-on-Si is analyzed using both cross-sectional and plan-view transmission electron microscopy. For comparison, simple thermal annealing of the GaAs-on-Si at higher temperature (850 °C) is also performed and analyzed. The reduction in the dislocation density that occurs with Zn diffusion is suggested to be due to the increased concentration of point defects generated during the Zn diffusion, resulting in enhanced dislocation climb. This mechanism is consistent with impurity-induced layer disordering, via Zn diffusion, in AlxGa1−xAs-GaAs heterostructures.