Layering of ultrathin SiO2 film and study of its growth kinetics

Abstract

A systematic kinetic study of SiO2 thin film thermally grown on Si(100) substrate by a single step and two step dry oxidation process is presented. Films grown at lower temperature (750°C) show higher density than films grown at higher temperature (1000°C). If the oxidation is carried out in two steps i.e., the first oxidation step at a lower temperature (750°C) and the second one at a higher temperature (1000°C), two distinct layers of SiO2 having different densities can be obtained. The film density was measured using the grazing incidence x-ray reflectivity technique. We also observed that when the thickness of the first “top” layer increases the growth of the “bottom” layer is retarded leading to lowering of total thickness of the SiO2 film even though the total oxidation time is increased.

Observation of an Interlayer in a Nano-Scale SiO₂ Layer on Si Substrate by X-Ray Reflectivity (XRR) Analysis

“…SiO 2 films are the most widely used dielectric materials in the solid state electronic and optoelectronic devices, and SiO 2 gate dielectric films with thicknesses of a few nanometers are used for an ultra-large scale integration in submicron electronic devices [1,2]. Since the physical properties of the thin film devices are strongly dependent upon the structural properties of the thin films such as thickness, surface and interface roughness, density and composition, precise control of the structural properties is critical to the optimum performance of the devices [3,4].…”

Surface Chemistry of Aerosolized Nanoparticles:Thermal Oxidation of Silicon

“…In 1965, Deal and Grove proposed a kinetic model for oxidation that postulates a mechanism in which oxidation occurs via oxygen migration through an oxide layer and eventual reaction with silicon at a silicon−silicon oxide interface . The model accurately describes the kinetics of thick oxide layer growth under wet (i.e., oxidation in the presence of water vapor) and dry conditions. , However, the Deal−Grove model does not adequately describe the growth of ultrathin oxide layers (<20 nm) from dry molecular oxygen. − Specifically, the observed growth rate of silicon oxide films 2.0−15.0 nm thick, produced under rapid thermal oxidation conditions, is much higher than that predicted from the Deal−Grove model. , Another problem is that oxide film thicknesses are typically measured by ellipsometry, for which uncertainties are in the 0.5−1.0 nm range. , Thus, to study the oxide film formation in nanoscale regime, a more accurate and sensitive measurement method of oxide thickness must employed.…”