Ultraviolet Laser Etching: Diatomic Temperatures by Laser-Induced Fluorescence Measurements

Laser-induced etching is receiving significant attention, motivated by applications in microelectronics and medicine and by long standing concern about optical damage phenomena. In the present experiments, we emphasize etching with pulsed UV (excimer) lasers in the low fluence, i.e. near threshold, region. Under these conditions etching has been attributed to a variety of phenomena, among them thermally activated vaporization and photochemical bond breaking processes. The present work is aimed at distinguishing between the thermal and electronic processes for several materials. According to the thermal model, one requires a sufficiently high peak temperature that vaporization is the primary source of surface etching.