Yield point and dislocation velocity of diamond and zincblende semiconductors in different temperature regimes

Abstract

Abstract The present paper puts forward the hypothesis that the yield point and dislocation velocity of tetrahedrally coordinated semiconductors exhibit two different temperature domains, with a transition from the low-temperature (LT) to the high-temperature (HT) regime at approximately 0.6T m (where Tm is the melting point). In the literature this aspect has not recieved much attention, and model parameters obtained in both domains are traditionally mixed together. The reason may be sought in the fact that, for experimental demands in most cases, the yield point is generally measured in the HT regime, while the dislocation velocity is investigated in the LT domain. This leads to a problem insofar as the lower yield stress (in the HT regime) usually obeys an exponential temperature and a power-law strain-rate dependence, while the dislocation velocity (in the LT regime) shows a more complicated dependence on stress and temperature in several cases, with activation energy and stress exponent depending on stress and temperature respectively. In the present paper the available measurements are reanalysed by taking into account that only data obtained in the same temperature range are compared. In this context, investigations of the dislocation velocities of Si, Ge and InSb extending to temperatures distinctly above 0.6T m, which have not attracted much interest in the literature, play a decisive role.