Laser-induced etching of Si surfaces: The effect of weak background light

Two different lasers were used to etch patterns on Si surfaces employing a thin film cell configuration. A strong, pulsed, 20 W KrF excimer laser was used for etching. A weak, cw, 5 mW HeNe laser provided background light. This laser, by itself, was incapable of etching the Si surface. A substantial enhancement of the laser etching process with background light was observed either when using many pulses or only one UV laser pulse. An even bigger change was observed as a function of the etchant concentration. (C) 1996 American Institute of Physics.