Atomic Scale Insights into Si Transport Pathway in Si-oxide Film Based on Theoretical Investigation of Medium Density Effects

Abstract

To elucidate the effect of medium strain on silicon (Si) transport in Si oxides, first-principles calculations were employed to evaluate the variation in the diffusion barrier of excess Si in isotropically strained quartz. Our results reveal that the barrier height exhibits significant dependence on density. The optimal barrier height, determined from the most stable metastable structure and the lowest transition state structure, was found to be 5.06 eV, in excellent agreement with the experimental value of 5.13 eV. Furthermore, a detailed analysis of experimental Si diffusion coefficients suggests that oxide films used in experiments can be categorized into at least two distinct types. This finding underscores the necessity of classifying oxide films based on structural characteristics rather than treating them as a single amorphous phase, ensuring a more precise understanding of their quality.