A Viscous Flow Model to Explain the Appearance of High Density Thermal SiO2 at Low Oxidation Temperatures

Higher density results from the thermal oxidation of Si in dry at lower oxidation temperatures. More than 3% higher density is observed for grown at 600°C as compared with 1150°C. A consistent model for the formation of this material is deduced based on the following: the temperature dependence of the density, the annealing behavior of the higher density , and on the literature and new measurements of the intrinsic stress in films. The model considers viscous flow of a Maxwell solid and hinges on the attainment of the necessary free volume for oxidation at lower oxidation temperatures.