Author(s)

N. Ali, V.F. Neto, Y. Kousar & J. Gracio

Abstract

Modulating CH4 flow during the fabrication of improved CVD diamond coatings N. Ali, V.F. Neto, Y. Kousar & J. Gracio Centre for Mechanical Technology and Automation, Department of Mechanical Engineering, University of Aveiro, 381 0- 193 Aveiro, Portugal Abstract Diamond films were deposited onto silicon using two processes, namely, Time- Modulated Chemical Vapour Deposition (TMCVD) and conventional CVD. The TMCVD process modulated the methane (CH4) flow during film growth, whereas, with conventional CVD, the CH4 flow was kept constant throughout the growth process. Diamond films deposited using TMCVD were smoother, harder and displayed better quality than similar films grown using conventional CVD. The TMCVD process promotes secondary nucleation onto the existing diamond crystals. Modulating CH4, consecutively, at hgh and low concentrations enables the depositing film to maintain its quality, in terms of diamond-carbon phase. Films grown under constant CH4 flow during diamond CVD displayed a c

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