Variation of spin densities and the solid-phase crystallization of amorphous Si1−xGex:H films

Abstract

We have investigated the solid-phase crystallization (SPC) of hydrogenated amorphous silicon–germanium (a-Si1−xGex:H) alloy films by using x-ray diffraction and electron spin resonance measurements. The films were deposited on glass in a plasma-enhanced chemical vapor deposition system by using SiH4 and GeH4 gases. The deposited films were then annealed at 600 °C, which resulted in crystallization. The variation of the spin densities with annealing time was found to be strongly correlated with the structural changes in the SPC process, and the Ge dangling bonds were the dominant defects involved in the SPC process for Si1−xGex:H films (for x>0.05). The incubation time and the final grain size of the recrystallized films depended on the Ge composition and were closely related to the variations of the Si–H and the Ge–H dissociation energies. The SPC process is thought to be influenced by the initial structural disorder of the a-Si1−xGex:H films, and by the Ge composition.