Dynamical recovery and self-diffusion in silicon

Abstract

The stress at the beginning of stage III of the strain-hardening curve has been measured as a function of temperature and strain rate in silicon single crystals. It is shown that the results can be successfully described by two current theories for steady-state creep, which were modified for the purpose of the dynamical test: the expression developed by Barrett and Nix (1965) on the basis of the diffusion-controlled motion of jogged screw dislocations and that of Mohamed and Langdon (1974) which is based on the diffusion-controlled climb of edge dislocations. For high temperatures the experimental results are fitted equally well by both theories while for low temperatures the agreement is better using the expression for the creep rate given by Barrett and Nix (1965). From this the activation energy of self-diffusion has been evaluated to be 3·6 eV; it may be ascribed to a mono-vacancy mechanism.