In situcrystallization of amorphous silicon in the transmission electron microscope

Amorphous Si thin films have been crystallized by in situ annealing in the transmission electron microscope. Crystallization occurred at about 700°C in electron-beam-deposited Si films, 400 Å thick, on amorphous Si3N4 substrates. Dendritic Si crystallites were observed with ⟨110⟩ and ⟨111⟩ orientations. The fast growth direction was parallel to ⟨112⟩. All crystallites were internally twinned with Σ = 3, {111} twin boundaries providing nucleation sites for atom attachment. The amorphous-crystal interface propagation was recorded on videotape to study the mechanism of crystallization. Interface velocities were measured at several temperatures and an activation energy of 3·36±0·23 eV was obtained for crystal growth.