Phenomenological model of reactive r.f.-magnetron sputtering of Si in Ar/O-2 atmosphere for the prediction of SiOx thin film stoichiometry from process parameters

The process of reactive sputtering from a silicon target in an Ar/O-2 gas m ixture is investigated. An optical plasma regulating circuit using the inte nsity of the 251.9 nm-Si I line as setpoint is employed to stabilize the sp uttering process. A phenomenological model of the process is derived that, in contrast to previous models, it allows to calculate the composition of t he growing SiOx film exclusively from measurable process parameters and acc ounts for the non-uniform deposition at the substrate. Film compositions x, predicted this way for different setpoints were verified by Rutherford bac kscattering spectroscopy. As an example, a SiO2/SiO1.5/SiO2 layer stack was prepared and via anneal transformed into a thin layer of nanocrystalline s ilicon embedded in an oxide matrix, a structure with potential for applicat ion in memory devices and Si-based light emitters. (C) 2001 Elsevier Scienc e B.V. All rights reserved.