Dielectric breakdown of SiO/sub 2/ thin films deposited by ion beam induced and plasma enhanced CVD

This paper presents a comparative study of SiO/sub 2/ thin films prepared at room temperature by ion beam induced chemical vapor deposition (IBICVD) and plasma enhanced chemical vapor deposition (PECVD) methods. The films are characterized by AFM, TEM, RBS, ERDA, NRA, X-ray reflectometry and spectroscopic ellipsometry. While the films prepared by IBICVD are very compact and dense and have a high refractive index, those prepared by PECVD exhibit a lower refractive index value, lower density and have a higher surface roughness. Films prepared by IBICVD present a breakdown electric field value (49.14 MV/cm), four times higher than that of the films prepared by PECVD (12.11 MV/cm) and other SiO/sub 2/ materials reported in the literature. This higher value is a consequence of the low roughness and high density of the IBICVD films. This type of microstructure is produced by the effect of the highly energetic ion beams (e.g. 400 eV) impinging on the surface of the growing films during their preparation.