High-rate homoepitaxial growth of CVD single crystal diamond by dc arc plasma jet at blow-down (open cycle) mode

Growth and applications of large size high quality single crystal diamond is one of the most significant progresses in the field of CVD diamond film research ever made in the past 15 years. However, up to now most of the works were done by microwave plasma CVD operating at high pressures. In the present investigation it is demonstrated that relatively high quality single crystal diamond layer with the FWHM of the diamond Raman peak of less than 2 cm(-1) and the FWHM of the diamond (400) reflection X-ray Rocking Curve of 0.028 degrees can be obtained by the 20 kW dc arc plasma jet operating at blow down (open cycle) mode at a growth rate as high as 36 mu m/h. The reason why dc arc plasma jet is also suitable for high quality epitaxial growth of single crystal diamond is that very high concentration of atomic hydrogen can be easily provided by the extremely high gas temperature due to the arc discharging. Detailed results on the effects of the ratio of H-2/Ar, the distance between the substrate to the anode nozzle of the arc plasma torch, the concentration of methane, and the substrate temperature on the growth of single crystal diamond are presented, and discussed comprehensively, and compared to that with the MWCVD, and with our previous work on the 30 kW dc arc plasma jet operating at arc root rotation and gas recycling mode. (C) 2014 Elsevier B.V. All rights reserved.