Silicon Oxidation Studies. Silicon Orientation Effects on Thermal Oxidation

摘要

The initial stage of the thermal oxidation of various crystallographic orientations of silicon reveals a complex rate behavior. This behavior is not understood within the conventional linear - parabolic model. A recently revised model which explicitly contains the areal density of Si atoms and mechanical stress effects is shown to provide both a qualitative and somewhat quantitative explanation of the complex substrate orientation effects. The purpose of this study is to analyze the crossover effect in terms of a recently proposed viscous flow model for Si oxidation. This model utilizes the notion of mechanical stress and viscous relaxation in SiO2 which occur as a result of the oxidation process on a Si substrate in addition to the other assumptions in the L-P model such as a steady state between the interface reaction and the transport of oxidant through the oxide. It is reported herein that the new viscous flow model provides a reasonable qualitative explanation for the crossover effect and in some instances a quantitative correlation of the effect.