Effects of Anodic Polarization Upon Electrochemically Grown Oxide Films on p‐Si, Studied by Ellipsometric and Capacitance Measurements

Electrochemically grown p‐Si/SiO2 structures were anodically biased in a glycol‐water‐KNO3 electrolyte at voltages below the growth voltage and studied as a function of time by means of ellipsometric and capacitance measurements. In all cases, including zero bias, further growth of the oxide film was observed by ellipsometry. The growth mechanism appeared to be different for low and for high biasing voltages. From the comparison between ellipsometric and capacitance results, additional evidence was collected for the hypothesis that water or a species originating from water diffuses into the oxide film, modifying its dielectric properties and possibly leading to erroneous determinations of the layer thickness by capacitance measurements.