IMPURITY-ASSISTED INTERVALLEY ELECTRON SCATTERING OF GERMANIUM AND SILICON UNDER UNIAXIAL COMPRESSION

Application of uniaxial stress along a particular crystallographic axis of a many-valley semiconductor causes up- and down-valleys in the momentum-energy space for electrons. The cyclotron resonance linewidth of the down-valley signals are broadened as a function of stress for certain doped germanium and silicon crystals. The electron transferred from up- to down-valley has an extra kinetic energy at the down-valley, corresponding to the valley energy difference, and the observed broadening is ascribed to the raised electron temperature there. From the broadening of the down-valley signal and observed down-to-up electron population ratio, the impurity-assisted intervalley scattering frequency is estimated for Ge/Ga, Ge/In and Si/P at 4.2°K. The magnitude is 1/20∼1/30 of the overall impurity scattering. There is an indication that it is strongly dependent of temperature. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.