SPECIES CHARGE AND OXIDATION MECHANISM IN THE CATHODIC PLASMA OXIDATION OF SILICON

This study discusses the sign of the charge of the gas phase species involved in the plasma oxidation of silicon and the oxidation mechanism itself in a system of a type previously reported in which oxidation occurs on a silicon surface facing away from a confined plasma. Based on grid-biasing experiments, it was found that the gas-phase oxygen species responsible for oxidation are positively charged, in marked distinction to what has been proposed for plasma anodization processes. From O-18 and Si-30 double-marker experiments, coupled with other information, the oxidation process was found to proceed by oxygen ion transport to the Si-SiO2 interface with no outdiffusion of silicon being detected.