HIGH-DENSITY SILICON-NITRIDE THIN-FILM IN PECVD

The aim of this work is to report the preparation and some chemical and physical properties of high-density silicon nitride thin films. The films are prepared by plasma-enhanced chemical vapor deposition (PECVD) at low frequency (50 kHz) with helium dilution and different silane/nitrogen/ammonia gas mixtures. In the best case the atomic hydrogen density is less than 7 x 10(21) atoms/cm3, mainly bound in NH sites, with a very low etch rate of 10 angstrom/min. The thermal stability and the diffusion barrier properties have been checked. This material must be a good candidate for chemical grafting and as a protective layer in chemical sensors.