Formation of shallow p(+) layers in GaAs.

The formation of shallow (0.05-0.2micron) p(+) layers in GaAs by pulse diffusion of Zn from a doped oxide source or by low energy implantation of Cd, Mg, Be or Zn ions was investigated by C-V etch profiling, secondary ion mass spectrometry and Hall effect measurements. Hole densities in excess of 10 (19) cm(-3) are easily obtainable by either of the two doping techniques, though the high temperature annealing or diffusion cycle must be kept to ~3s at ~1000C to prevent excessive movement of the acceptor species. For the regular production of p(+) regions, implantation is obviously the preferred technique because of its advantages of uniformity and reproducibility, however for production of extremely shallow layers with high surface concentrations, pulse diffusion of Zn must be used.