Dynamics of Q-switched laser annealing

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Abstract
Using time‐resolved optical‐reflectivity measurements, the duration of the thin liquid layer accompanying Q‐switched laser annealing in Si, Ge, and GaAs has been determined. The duration of this melted layer has been studied as a function of laser energy at 1.06‐ and 0.53‐μm wavelength for both implanted and unimplanted samples. Thresholds for initiation of melting and damaging the surface are obtained directly. With the aid of channeling–Rutherford‐backscattering measurements, the duration of melt necessary for annealing implanted samples is determined. Results for unimplanted silicon at 530 nm are compared with recent numerical calculations. In addition, measuremnts of the fall time of the reflectivity as the liquid‐solid interface approaches the surface enables us to estimate regrowth velocities. A simple scheme is also discussed for efficient annealing with dual wavelengths.