Optical Measurement of Film Growth on Silicon and Germanium Surfaces in Room Air

Abstract

The thickness and growth kinetics of oxide films on polished silicon and germanium exposed to room air after having been rinsed in hydrofluoric acid were obtained by measuring the ellipticity of reflected polarized light. Film growth obeys the Elovich equation. Plots of thickness vs. the logarithm of the time in air are linear after about 15000 sec with slopes of 6.8Aå/decade (Si) and 8.1Aå/decade (Ge). Immediately after the hydrofluoric acid rinses the films are 10–15Aå thick and increase in thickness by about 11–12Aå after one day in air. A small part of the films dissolves in certain organic liquids. Measurements of ellipticity at two angles of incidence during film growth gave an experimental check of the optical theory.