On the stress dependence of the dislocation velocity in silicon

Abstract

The velocity of 60°- and screw-dislocations in silicon is measured at 422°C (0.41Tm) in a wide range of stresses (50 MPa ≦ τ ≦ 300 MPa). The double etching technique is used taking into account the individual depth of bending of the 60° dislocations below the surface. Dislocations of four different glide systems are investigated exhibiting clearly different stress exponents m = = d ln v/d ln τ. This exponent appears to be composed of two parts; one part depends on the climb force acting on the dislocation and is interpreted as a consequence of the change of the Peierls potential by core deformation. The second part depends on temperature and dislocation type.