Preferential nucleation along SiO2 steps in amorphous Si

Abstract

Annealing characteristics for amorphous Si film deposited on an SiO2 layer were investigated with the hope that this would throw further light on aspects of solid phase epitaxy. Preferential nucleation, which initiated from the bottom region of deposited Si film, was found along SiO2 steps. The activation energy for the growth speed of the nuclei was evaluated to be 1.7 eV. As this value is significantly smaller than 2.0 eV, the bond breaking energy of Si, stress originating mainly from the thermal expansion difference between SiO2 and Si, is considered to be the driving force.