Optical and Other Properties of MPACVD Diamond

Abstract

The exceptional properties of diamond have stimulated a considerable research effort into the low pressure synthesis of diamond thin films for a diverse range of applications including:- tribological coatings, semiconductor heat sinks and (as in this work) protective optical coatings. Numerous deposition techniques have been reported in the literature including Microwave Plasma Assisted CVD (MPACVD). This paper briefly describes the MPACVD deposition system used at Plessey Research Caswell Ltd and outlines the effects of important deposition parameters on the growth morphology of diamond crystallites and thin films. Techniques including SEM, TEM and X-ray diffraction have been used to study the growth mechanisms of MPACVD diamond. IR and Raman spectroscopy have been used to characterise the deposited films and an IR reflection technique is described for studying the infrared properties of the layers. The effect of deposition parameters on the properties of diamond thin films is discussed with regard to the use of these films for protecting IR windows and domes.