A Novel Model of the H Radical in Hot-Filament Chemical Vapor Deposition

Amorphous hydrogenated and crystalline silicon thin films were prepared by hot-filament chemical vapor deposition. A structural transformation from amorphous phase to crystalline phase by increasing the filament temperature T _fil from 1600 °C to 1650 °C was observed. This phenomenon may result from the associated abundance of H radicals participating in the growth of the films. A probability distribution model of the H radical is proposed to elucidate this phenomenon. According to this model, the phase transition is due to a distinct difference in the probability distribution of the H radicals, which seems to be dependent upon T_fil.