EVOLUTION OF AN IMPURITY BAND DURING LOW-TEMPERATURE APPLICATION OF AFIELD TO WEAKLY COMPENSATED SILICON WITH A HIGH DOPING LEVEL

When an electric field is applied to Si:B with a boron concentration o f 10(17-18) cm(-3) at low temperatures, surface conduction channels fo rm at relatively high voltages on the field electrode. The particular voltage varies with the doping level. When the Si surface becomes depl eted of holes, the effect stems from the generation of a fluctuation p otential due to impurity charge exchange. In the case of enrichment, i n contrast, the effect stems from a filling of the upper Hubbard band under conditions of a hole-gas quantization. (C) 1994 American Institu te of Physics.