Growth Mechanisms During Thin Film Crystallization From the Melt

Recent experiments on strip heater scan-melted silicon films over SiO2 have revealed the existence of two regimes of Si solidification separated by an abrupt discontinuity as the thermal gradient, in the region of the freezing front is varied. If is reduced to below is equivalent to 4 degrees K/mm the scan-' recrystallized Si films are found to have long straight non-branched subboundaries with tilt misalignment of 0.1 degrees or less, a lateral spacing usually in excess of 50 micron, and to consist of rows of threading dislocations. This is in marked contrast to material scan recrystallized at higher which shows conventionally branched 1 degree to 3 degree subboundaries that consists of edge dislocations running in the plane of the film.