Time-resolved ellipsometry measurements of the optical properties of silicon during pulsed excimer laser irradiation

Abstract

A technique has been developed for continuously carrying out time-resolved ellipsometric measurements on the nanosecond timescale. Using this technique, the optical properties of silicon have been measured during and immediately after pulsed excimer (KrF, λ=248 nm) laser irradiation. From these data the optical functions of liquid silicon at λ=632.8 nm have been determined to be n=3.8 and k=5.2±0.1, in minor disagreement with the results of Shvarev, Baum, and Gel’d [High Temp. 15, 548 (1977)]. The surface temperature before and after melting was also continuously determined by comparing these results with elevated constant-temperature measurements of the optical functions. The results demonstrate that time-resolved ellipsometry is a powerful technique for examining changes in optical properties on the nanosecond timescale.