Reduced subboundary misalignment in S0I films scanned at low velocities.

Silicon-on-insulator (S0I) films on Si0(2) scan-melted at low velocities (20 to 300 micron/sec) with reduced thermal gradients at the melt-freezing interface are found to have qualitatively different properties from similar films melt- scanned at higher gradients and scan velocities. The transition between the two regimes appears to be abrupt. Scanning at intermediate velocities often results an admixture of patches containing one or the other type of material. The slow scan regime is characterized by long straight non-branched subboundaries having a lateral spacing 5-60 micron, and very small tilt misalignments of 0.1 degrees or less. These slow scan subboundaries are found to consist largely of threading dislocations in contrast conventional subboundaries which are tilt boundaries of up to 3 degrees and typically consist of edge dislocations running in the plane of the film.