Non-Arrhenius reorientation kinetics for the B-H complex in Si: Evidence for thermally assisted tunneling.

Abstract

The B-H complex in Si can be aligned by stress and reorients with an activation energy of roughly 0.2 eV. We combine new measurements of the reorientation kinetics of the B-H complex made by the stress-induced dichroism technique with previous internal friction results to show that the reorientation kinetics are non-Arrhenius. These results support Stoneham's suggestion Phys. Rev. Lett. 63 1027 1989 that reorientation occurs by thermally assisted tunneling. We have also discovered the remarkable fact that the reorientation rate for B-D is greater than that of B-H for $T>57$ K.