Determination of the phonon modes involved in the carrier-phonon interaction in silicon inversion layers at low temperatures by nonohmic transport measurements

Abstract

A study of nonohmic carrier transport in high magnetic fields in silicon inversion layers is presented in a range of lattice temperatures between 1.5 and 10 K. Carrier temperatures ${T}_{C}$ as a function of the electric field are deduced from measurements of the amplitudes of Shubnikov-de Haas oscillations in dependence on lattice temperature ${T}_{L}$ and electric field $E$ at carrier densities in the inversion layer larger than 1\ifmmode\times\else\texttimes\fi{}${10}^{12}$/${\mathrm{cm}}^{2}$. The temperature and field dependence of the mean energy loss per carrier $〈\frac{d\ensuremath{\epsilon}}{\mathrm{dt}}〉=\frac{\ensuremath{\sigma}{E}^{2}}{n}$ is used to determine the phonon modes involved in the carrier-phonon interactions. It is found that in silicon inversion layers of metal-oxides-semiconductor structures scattering by acoustic phonons is the dominant carrier-phonon interaction at low temperatures. In high-mobility samples the two-dimensional behavior of the electron gas dominates the carrier-phonon interaction whereas in low-mobility devices ($\ensuremath{\mu}<1000$ ${\mathrm{cm}}^{2}$/V sec at 4.2 K) energy-level broadening has to be considered. In this case bulklike phonons must be incorporated. In $p$-type inversion layers a possible contribution of surfon scattering cannot be ruled out.