Application of thin silicon films to closed-tube Si and Zn diffusion in GaAs and AlxGa1−xAs

Abstract

The application of thin Si films for selective area Si and Zn diffusion into GaAs and AlGaAs is described in detail. The concentration-dependent pair diffusion coefficient and the activation energy for Si diffusion into AlxGa1−xAs under As overpressure for 0≤x≤0.8 are measured using both secondary ion mass spectrometry and junction depth studies. Furthermore, Si films are seen to act as an ideal mask for Zn diffusion at temperatures below 750 °C. Ideal lateral Zn diffusion profiles are routinely observed using these films, independent of stress at the interface which provides new insight into the nature of laterally enhanced diffusion.