Thermally induced recrystallization of textured hydrogenated nanocrystalline silicon

By an analysis of the local crystallinity based on model potential molecular dynamics simulations we investigated the effect of dissolved hydrogen on the thermally induced recrystallization of nanocrystalline silicon. By using the Kolmogorov-Johnson-Mehl-Avrami theory to analyze the atomistic data, we find that the recrystallization rate decreases exponentially with the hydrogen contamination. At low concentration, the kinetics is moderately affected by the H atoms that tend to migrate to the boundaries increasing their effective interface. At higher H content, we find an increasing number of SimHn hydrides that affect the crystalline order of the material and severely impede recrystallization. The analysis based on crystallinity is supported by the atomic scale study of the recrystallization mechanism, here identified as an inverted bond-switching process, and by the ability of hydrates to pin the amorphous-crystalline boundaries.