STUDIES OF HYDROGEN-ION BEAM CLEANING OF SILICON DIOXIDE FROM SILICON USING INSITU SPECTROSCOPIC ELLIPSOMETRY AND X-RAY PHOTOELECTRON-SPECTROSCOPY

The removal of a thin oxide layer from a silicon substrate without significant damage has been achieved at temperatures as low as 500-degrees-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-degrees beam incidence, and 500-degrees-C substrate temperature.