PULSED LASER-INDUCED DAMAGE THRESHOLD OF THIN ALUMINUM FILMS ON QUARTZ - EXPERIMENTAL AND THEORETICAL-STUDIES

Pulsed 532-nm laser-induced damage thresholds of aluminum films on qua rtz were systematically measured for film thickness ranging from 13 to 50 nm, using simple yet reliable acoustic and optical techniques. Exp erimental data were found to be consistent and reproducible, and could be satisfactorily simulated by a one-dimensional heat diffusion model with a temperature-dependent absorptance. Damage thresholds measured with the acoustic probe (interpreted as evaporative events) were in th e 30- to 100-mJ/cm(2) range, which are about 30% higher than those mea sured with the optical probe (interpreted as melting events). This sma ll difference is consistent with the temperature-dependent absorptance assumption, and helps to explain the unexpected sensitivity of the ac oustic probe relative to the optical probe, especially for thicker fil ms. (C) 1996 American Institute of Physics.