Pal, Kalyan Sundar and Bysakh, Sandip and Mallik, Awadesh Kumar and Dandapat, Nandadulal and Datta, Someswar and Guha, Bichitra Kumar (2015) Influence of growth conditions on microstructure and defects in diamond coatings grown by microwave plasma enhanced CVD. Bulletin of Materials Science, 38 (3). pp. 717-724. ISSN 0250-4707

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Abstract

Diamond coatings were grown on SiO2/Si substrate under various process conditions by microwave plasma chemical vapour deposition (MPCVD) using CH4/H-2 gas mixture. In this paper, we present a microstructural study to elucidate on the growth mechanism and evolution of defects, viz., strain, dislocations, stacking faults, twins and non-diamond impurities in diamond coatings grown under different process conditions. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy were used to characterize the diamond coatings. It has been shown that our new approach of prolonged substrate pre-treatment under hydrogen plasma yielded a new growth sequence that the SiO2 layer on the Si substrate was first reduced to yield Si layer of similar to 150 nm thickness before diamond was allowed to grow under CH4-H-2 plasma, created subsequently. It has also been shown that Si and O as impurity from the substrate hinders the initial diamond growth to yield non-diamond phases. It is being suggested that the crystal defects like twins, stacking faults, dislocations in the diamond grains and dislocations in the intermediate Si layer are generated due to the development of non-uniform stresses during diamond growth at high temperature.

Item Type:	Article
Subjects:	Microstructure and Characterization
Divisions:	Bioceramics & Coating
Depositing User:	Bidhan Chaudhuri
Date Deposited:	01 Jan 2016 09:26
Last Modified:	01 Jan 2016 09:26
URI:	http://cgcri.csircentral.net/id/eprint/3059

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