Selective thermal decomposition of ultrathin silicon oxide layers induced by electron-stimulated oxygen desorption

The mechanism of electron-beam-induced selective thermal decomposition of ultrathin oxide layers on Si surfaces was studied by scanning reflection electron microscopy, Auger electron spectroscopy, and x-ray photoelectron spectroscopy. We found that the change in the oxide layer composition caused by electron-stimulated oxygen desorption accounted for the selective thermal decomposition, where nanometer-scale voids were densely generated at a low heating temperature (720 degrees C). This implies that oxygen desorption from the oxide layers promotes the formation of a volatile oxide (SiO), and generates void nucleation sites. (C) 1997 American Institute of Physics.