DETERMINATION OF THE REFLECTIVITY OF LIQUID SEMICONDUCTORS OVER A WIDE TEMPERATURE-RANGE

A new method for the determination of the reflectivity of liquid semiconductors in the temperature range from the melting point to the boiling point is presented in the paper. The method is based on the pulsed laser irradiation of the semiconductor surface, the time-resolved reflectivity (TRR) measurement technique, and the numerical simulation of the process using a nonequilibrium thermal model. Matching the experimental and computed values of the maximum reflectivity of the cw probe laser and the surface melt duration in the dependence on energy density of the laser pulse and a least-squares-based fitting procedure lead to the determination of the reflectivity of the liquid at the wavelength of the primary laser beam. The method is illustrated by experimental data on XeCl (308-nm) and ArF (193-nm) excimer laser irradiation of Si(100), giving the results B-1 = 0.67 +/- 0.01 - (8 +/- 1) x 10(-5) (T-1687) at 308nm and R(1) = 0.755 +/- 0.010 - (7 +/- 1) x 10(-5) (T-1687) at 193nm, where R(1) is the reflectivity of the liquid and Tis temperature in K.