Galeckas A, Linnros J, Pirouz P
Department of Microelectronics and Information Technology, Royal Institute of Technology, Electrum 229, SE-164 40 Stockholm, Sweden.
Phys Rev Lett. 2006 Jan 20;96(2):025502. doi: 10.1103/PhysRevLett.96.025502. Epub 2006 Jan 18.
We report on optically induced nucleation and expansion of stacking faults in hexagonal SiC structures. The activation energy for partial dislocation glide under optical excitation is found to reduce to 0.25 +/- 0.05 eV, which is about 2 eV lower than for pure thermal activation. From the measurements of thermal activation and below-gap excitation spectroscopy of dislocation glide, we conclude that the elementary process controlling expansion of stacking faults is kink pair nucleation aided by the phonon-kick mechanism. We propose that solitons on 30 degrees Si(g) partials with a silicon core act as deep 2.4 eV + Ev trap sites, readily providing electron-hole recombination energy to enhance the motion of dislocations. Our results suggest that this is a general mechanism of structural degradation in hexagonal SiC.
