Studies of hydrogen ion beam cleaning of silicon dioxide from silicon using in situ spectroscopic ellipsometry and x-ray photoelectron spectroscopy

Abstract

The removal of a thin oxide layer from a silicon substrate without significant damage has been achieved at temperatures as low as 500 °C using a low‐energy hydrogen ion beam produced by a high‐intensity and low‐energy ion source in a high‐vacuum system. In situ spectroscopic ellipsometry was found to be a sufficiently sensitive and nondestructive method for simultaneously monitoring silicon surface cleaning and ion‐induced substrate damage. This letter reports the optimum cleaning parameters for silicon (i.e., minimum ion‐induced damage with maximum etch rate of SiO₂) to be 300 eV ion beam energy, 60° beam incidence, and 500 °C substrate temperature.