Nanoscale structural investigation of Si crystallites grown from silicon suboxide films by thermal annealing

Abstract

Nanoscale structures of Si crystallites were investigated using a high-resolution transmission electron microscope (HRTEM). Si crystallites, a few nanometers in size, were grown from amorphous silicon suboxide (a-SiO x, x < 2) films by thermal annealing at 1000–1100°C. It was considered that the crystallites were grown through the precipitation, nucleation and phase transition from amorphous to crystal, of the excess Si atoms forming the stoichiometric SiO 2 network during the thermal annealing. The growth of the Si crystallites was dependent on the oxygen content x, which suggested the presence of a critical content, x c. Surface facetting and anisotropic growth of the Si crystallites were observed to result from dependence of the growth rate on the lattice planes of Si. Twins and stacking faults were occasionally observed in the {111} lattice planes of the Si crystallites. These atomic-scale structures are considered to be characteristic of the solid-phase crystallization of Si. PACS 61.16.Bg 68.35.Rh