6 research outputs found
Theoretical study of kinks on screw dislocation in silicon
Theoretical calculations of the structure, formation and migration of kinks
on a non-dissociated screw dislocation in silicon have been carried out using
density functional theory calculations as well as calculations based on
interatomic potential functions. The results show that the structure of a
single kink is characterized by a narrow core and highly stretched bonds
between some of the atoms. The formation energy of a single kink ranges from
0.9 to 1.36 eV, and is of the same order as that for kinks on partial
dislocations. However, the kinks migrate almost freely along the line of an
undissociated dislocation unlike what is found for partial dislocations. The
effect of stress has also been investigated in order to compare with previous
silicon deformation experiments which have been carried out at low temperature
and high stress. The energy barrier associated with the formation of a stable
kink pair becomes as low as 0.65 eV for an applied stress on the order of 1
GPa, indicating that displacements of screw dislocations likely occur via
thermally activated formation of kink pairs at room temperature