Interfacial reactions of Y and Er thin films on both (111)Si and (001)Si have been studied by transmission electron microscopy (TEM). Epitaxial rare-earth (RE) silicide films were grown on (111)Si. Planar defects, identified to be stacking faults on {1010} planes with 1/6<1213> displacement vectors, were formed as a result of the coalescence of epitaxial silicide islands. Double-domain epitaxy was found to form in RE silicides on (001)Si samples resulting from a large lattice mismatch along one direction and symmetry conditions at the silicide/(001)Si interfaces. The orientation relationships are [0001]RESi 2-x // [110]Si, (1100)RESi 2-x //(001)Si and [0001]RESi 2-x /[110]Si, (1100)RESi 2-x //(001) Si. The density of staking faults in (111) samples and the domain size in (001) samples were found to decrease and increase with annealing temperature, respectively.

High-resolution transmission electron microscopy (HRTEM) in conjunction with auto-correlation function (ACF) analysis has been applied to investigate the crystallization processes in amorphous silicon. For both electron beam evaporated and ion implanted amorphous silicon thin films, a high density of Si nanocrystallites was detected in as-deposited films. The density was found to diminish in amorphous films with annealing temperature first then increase. The conclusions are discussed in the context of free energy change with annealing temperature.