The effects of degeneracy on doping efficiency for n−type implants in GaAs

Abstract

The effect of degeneracy on doping efficiency for n−type implants in GaAs is computed by assuming the donor energy level to be coincident with the bottom of the conduction band. For such a case the Fermi level will always lie in the conduction band, and as a result the sheet carrier concentration can be substantially less than the implanted dose. Computations are given which show that peak carrier concentrations cannot readily exceed ∼5×10¹⁸/cm³ and doping efficiency (as conventionally measured) can be as low as 5−10% under common implantation conditions.