Multiscale Modeling Study of Native Oxide Growth on a Si(100) Surface

Silicon and its native oxide SiO2are the most commonly used materials in semiconductor device technology. After decades of research in this field, details of the initial oxidation and the subsequent O migration and amorphization are still a subject of interest. In this paper, we present a multiscale modeling approach to investigate the oxidation process of a Si(100) surface. Starting from the adsorption and dissociation of single O2 molecules, we further extended our investigations towards the initial oxidation of the first Si layer and subsequent O migration. Finally, we construct a realistic model of a Si/SiO2 interface consisting of around 5000 atoms. The employed simulation techniques used in this study range from density functional theory (DFT) to density functional based tight binding (DFTB) to classical molecular dynamics (MD).

I. Introduction

The thermal oxidation process of silicon has been of general interest for researchers in both engineering and scientific fields during the last five decades [1]. The Si/SiO₂ interface is unrivaled in terms of quality and usability for nano-technologies. The interplay between Si and O gains even more importance since oxygen is one of the most common impurities in commercially grown single-crystalline silicon [2]. With the continuous downscaling trend for smaller devices, understanding the initial surface oxidation as well as the growth of amorphous SiO₂ (a-SiO₂) on a Si substrate becomes crucial.