HOT-ELECTRON EFFECTS IN 2DEGS IN SI OF LOW NDEPL

Studies have been made of Si 2DEGS formed on (001) high resistivity (r ho approximately 1000-OMEGA-cm) p-type substrates in the hot-electron region. Thermal population of an excited subband leads to a decrease i n resistance in contrast with the increase seen in 2DEGS formed on low er resistivity substrates, and this suggests that mu(E(ex)) > mu(E(o)) in these samples, though which of the excited subbands, E'(o) or E1, is lowest is not known. Tensile stress measurements indicate that mu(E '(o)) > mu(E(o)) and this is attributed to the greater average distanc e of the electrons from the interface resulting from their weaker conf inement in high-resistivity substrates.