Increasing of dislocation mobility by heat treatment of deformed pure and doped InP crystals

The influence of dopant impurity type on the dislocation mobility in InP crystals is investigated. It is shown that the dislocation mobility (γ, γs) under action of a concentrated load depends on impurity type and deformation temperature. The critical temperature (Tcr) of dislocation activation for pure and iron doped InP is close to 600 K. The donor impurity (Sn) displaces Tcr towards low temperatures (T≈550 K) and raises the γ and γs parameters. Acceptor impurity leads to increase of Tcr (>800 K) and decreases the γ and γs values. The nature of this phenomenon consists in change of the lattice parameter (a) of the InP crystals — a is increased by doping with donor impurity and decreased by acceptor doping. The deformation (dislocation and twinning) mechanisms are concerned with the size of lattice parameter as well.