Microwave hot electron effects in semiconductor quantized inversion layers

Hot electron microwave conductivity of quantized inversion layers in semiconductor surfaces has been calculated based on a displaced Maxwellian approximation for the electron distribution function. The calculations performed take into account repopulation of carriers among the various subbands. The effects of the energy, momentum and intervalley population exchange rates due to scattering by acoustical and intervalley phonons are included in the derivations. The results are applied to silicon where the electron energy and momentum losses by intervalley phonons in both the zero-order coupled and first-order coupled cases are important. Numerical computations for the microwave conductivity of silicon are presented as a function of bias electric field and frequency. It is found that significant changes in the conductivity contribution for a fixed bias field occur at frequencies on the order of the intervalley repopulation rate. Though no experimental work in this frequency range has been performed, it should be easily observable.