Infrared Measurement of Carrier Density, Lattice Temperature and Melt Depth during Nanoseoond Pulsed Laser Annealing of Silicon and Germanium

We have performed infrared reflectivity measurements using 5.3 and 10.6μm probes to determine the plasma density, lattice temperature and melting kinetics of silicon and germanium following excitation by 25 nanosecond, 0.53 and 1.06μm pulses. Below the threshold of melting, the maximum plasma densities are approximately 1020 cm−3 for both materials; these values and the spatial and temporal evolution of the plasma are consistent with well known generation, diffusion and recombination processes. Above the threshold for melting we have taken advantage of the large skin depth at infrared wavelengths to determine the melt front kinetics for depths up to 1000 Å using a contactless technique.