Sensitivity of Si diffusion in GaAs to column IV and VI donor species

Secondary ion mass spectroscopy and carrier concentration measurements are used to characterize Si diffusion into GaAs wafers containing two fundamentally different forms of donors, the column IV donors Si or Sn and the column VI donors Se or Te. A decrease in the Si diffusion rate is found in GaAs containing the column VI donors compared to the column IV donors. This trend is consistent with the model in which the Si diffuses as donor‐gallium‐vacancy complexes. The decrease in the Si diffusion coefficient is attributed to the greater binding energy of column VI donor‐gallium‐vacancy nearest‐neighbor complexes, thus reducing the concentration of free‐gallium vacancies available to complex with the Si.