Sub-boundary formation and suppression in silicon films recrystallized by scanned zone melting.

We observe that the formation of low angle grain boundaries (sub-boundaries) depends strongly on the thickness of the recrystallized Si film. The average lateral spacing between adjacent sub- boundaries increases from 40microns for 4000 angstrom films to 500micron for unseeded Si films 30micron thick. For seeded 30micron Si films on 1.6 mm by 1.6 mm buried oxide islands, areas exceeding 1.0 mm by 1.0 mm have been recrystallized which are free of all sub-boundaries, but which contain dislocations in other configurations.