Annealing and recrystallization of hydrogenated amorphous silicon - art. no. 075403

Using a combination of positron annihilation and x-ray-diffraction techniqu es, we have shown that low hydrogen concentration hot wire chemical vapor d eposition grown a-Si:H forms a continuous random network with no detectable free volume in the form of microvoids, and no evidence of a microcrystalli ne phase. On annealing up to 400 degreesC, the amorphous network is seen to relax and the first stages of recrystallization occur. There is also evide nce of vacancy clustering to form a low concentration of microvoids. The st ructural relaxation has a very low activation energy, around 0.1 eV, and is probably caused by a reconfiguration of hydrogen-terminated dangling, bond defects. The formation of microvoids and the recrystallization can both be interpreted by the migration of unterminated dangling-bond defects.