Effects of oxygen content on properties of silicon oxide films prepared at room temperature by sputtering-type electron cyclotron resonance plasma

We present the study of the effects of gas-phase oxygen fraction on properties of silicon oxide films prepared in a sputtering-type electron cyclotron resonance plasma discharge. Dielectric breakdown characteristics of the films are considerably improved by an increase in oxygen flow rate, F-O2, with a constant Ar gas flow rate of 16 sccm. Films prepared at F-O2 of more than 6 sccm have good dielectric breakdown fields of 9-11 MV/cm, which are comparable with those of high quality thermally grown SiO2. Moreover, the increase of F-O2 improved structural properties of the films. Detailed measurements of their composition and microstructure were carried out using ellipsometry, chemical etch rate measurement in a mixture of HF, H2O, and HNO3 (P etch), x-ray photoelectron spectroscopy and infrared spectroscopy techniques. Ellipsometry and XPS measurements indicated that films prepared at F-O2 of more than 3 sccm are stoichiometric. Dependence of the IR spectra and P etch rate on F-O2 of more than 3 sccm indicated that distribution of Si-O-Si bond angle and Si-O bond strain in the films decreases with an increase of F-O2. Based on the behavior of the Si-O-Si bond angle and refractive index of the films, we discuss the improvements in structural properties in terms of growth kinetics. (C) 1998 American Institute of Physics. [S0021-8979(98)03520-8]