Reflectivity of Silicon-on-Sapphire During Pulsed Laser Annealing

Abstract

ABSTRACTUsing a visible probe laser (632.8 nm) we have directly observed motion of the melt front in silicon-on-sapphire during pulsed laser annealing. The average penetration and regrowth velocities have been determined to be 13 and 6.5 m/sec. respectively. These values are in agreement with recent conductivity measurements and heat flow calculations. In addition, the data demonstrate that the high-reflectivity phase can penetrate at least .5 um (Si thickness) and requires a significant amount of the time to do so. These results are further evidence that the high–reflectivity phase is molten silicon.