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      Permanent link:
      https://www.ias.ac.in/article/fulltext/boms/038/03/0717-0724

    • Keywords

       

      Microwave plasma CVD; polycrystalline diamond; transmission electron microscopy; microstructure; defects.

    • Abstract

       

      Diamond coatings were grown on SiO2/Si substrate under various process conditions by microwave plasma chemical vapour deposition (MPCVD) using CH4/H2 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 ∼150 nm thickness before diamond was allowed to grow under CH4–H2 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.

    • Author Affiliations

       

      Kalyan Sundar Pal1 2 3 Sandip Bysakh1 Awadesh Kumar Mallik1 Nandadulal Dandapat1 Someswar Datta1 Bichitra K Guha2

      1. Central Glass & Ceramic Research Institute, Kolkata 700 032, West Bengal, India
      2. Department of Physics, Indian Institute of Engineering Science and Technology, Howrah 711 103, India
      3. National Test House (ER), Kolkata 700 091, India
    • Dates

       

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