NANOSCALE STRUCTURAL INVESTIGATION OF SI CRYSTALLITES GROWN FROM SILICON SUBOXIDE FILMS BY THERMAL ANNEALING

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-SiO2, x < 2) films by thermal annealing at 1000-1100 degrees C. II was considered that the crystallites were grown through the precipitat ion, nucleation and phase transition from amorphous to crystal, of the excess Si atoms forming the stoichiometric SiO2 network during the th ermal annealing. The growth of the Si crystallites was dependent on ti le oxygen content x, which suggested the presence of a critical conten t, x(c). Surface facetting-and anisotropic growth of the Si crystallit es were observed to result from dependence of the growth rate on the l attice planes of Si. Twins and stacking faults were occasionally obser ved in the {111} lattice planes of the Si crystallites. These atomic-s cale structures are considered to be of the solid-phase crystallizatio n of Si.