Precisely controlled shallow p+ diffusions in GaAs

Precisely controlled shallow p+ diffusions have been made in GaAs using ZnO/SiO2 as a doped oxide source for zinc, and a layer of phosphosilicate glass as a cap. Diffusions were made in an open-tube system with a nitrogen gas ambient, and exhibit a junction depth reproducibility of better than ±5%. The technique is shown to be relatively insensitive to all process parameters other than diffusion time and temperature, and to be comparable in convenience and ease to diffusion in silicon.