STUDY OF THE INFLUENCE OF THE PHOSPHORUS PRESSURE ON THE PREPARATION OF NOMINALLY UNDOPED SEMI-INSULATING INP WAFERS

The conditions for the preparation of nominally undoped semi-insulating (SI) InP wafers by annealing under controlled phosphorus pressure are described. It is demonstrated by the results of electrical profile measurements (differential Hall effect) and by photoluminescence that diffusion effects in a thin peripheral layer (almost-equal-to 20-mu-m) can be correlated to a phosphorus in- and indium out-diffusion. But diffusion of these species is correlated to a donor behavior and relatively slow. It can, therefore, not be used to explain the SI bulk property which seems not to depend on the phosphorus overpressure during annealing.