Diamond thick film deposition in wafer scale using single-cathode direct current plasma assisted chemical vapour deposition

Abstract

Deposition behavior of CVD diamond thick film by direct current (DC) plasma assisted chemical vapour deposition method was investigated on a wafer scale of 4 inches (10 cm) in diameter. A diode configuration with a cathode connected to the DC power supply and a grounded substrate was used, on which diamond was deposited. Plasma of methane and hydrogen mixed gas was generated at 150 Torr with the power up to 50 kW. Typically wafers showed a thickness gradient in a radial direction. A wafer bowing was also observed due to residual stress in the film. Both the thickness gradient and the bow could be minimized by process control. The physical properties such as Raman characteristic and thermal conductivity were very uniform. The average growth rate increased with methane concentration up to 19 mum/h, which could be increased further by increasing methane concentration and input power. (C) 2003 Elsevier Science B.V. All rights reserved.