Computational simulations of pulsed laser induced melting and solidification of monocrystalline GaSb

Numerical analysis of pulsed laser induced phase change processes in the ne ar-surface region of monocrystalline bulk GaSb is done using a thermal none quilibrium model. The calculations of basic parameters of the processes suc h as surface melt duration, maximum reflectivity of the probe laser beam, e tc., are verified using results of experimental work on GaSb samples irradi ated by the ruby (694 nm, 35 ns FWHM) and ArF (193 nm, 13 ns FWHM) lasers. The comparison of experimental data with numerical predictions shows that w hile for the ruby laser a reasonable agreement in surface melt duration is achieved. the results for the ArF laser differ quite a lot. The amorphizati on of the topmost surface layer is identified as a main reason for these di fferences. The subsequent experimental analysis of the surface structure by low energy electron diffraction (LEED) and Auger electron spectroscopy (AE S) confirms the theoretical predictions and clearly indicates the appearanc e of an amorphous GaSb structure after ArF laser irradiation. (C) 2000 Else vier Science B.V. All rights reserved.