Ultraviolet laser-induced ion emission from silicon

Abstract

Si and Ge ion ejection is observed to occur from clean silicon and germanium surfaces upon excimer laser irradiation at fluences (0–150 mJ/cm2) well below that necessary to cause thermionic emission or melting of the substrate. Quadrupole mass spectrometric techniques were employed to for the detection of emitted positive ions. Laser intensity dependent measurements were performed at 193, 248, and 351 nm to elucidate the laser fluence and photon energy threshold behavior of each of the charged species.