Formation of submicron oxide widths on aluminum in the presence of keV electron beams and CO2 or N2O

Abstract

The purpose of this paper is to report the size of oxide islands or line w idths that can be grown as smaller diameter electron beams are used for the ox idation. The implications of the potential lateral resolution available b etween oxide  lines  for electronic materials are discussed. The localize d oxide growth on thin Al films occurs in the presence of .5 to 10 keV ele ctron beams and high vacuum level pressures of carbon dioxide or nitrous o xide. Auger electron spectroscopy shows saturation of the O (KLL) signal and depletion of the Al (LMM) signal after an exposure of 5000 l carbon di oxide with a 2 keV beam of 7 A/sq. cm. The oxide is spatially restricted to the beam impact region and is stable for long periods of time in vacuum . The most plausible mechanism for this oxide growth is dissociation of t he carbon dioxide or the nitrous oxide by the electron beam in the region of impingement on or near the surface. Oxygen atoms thus formed can then react with the Al, and carbon monoxide or nitrogen desorbs. (AIP)