Economical deposition of a large area of high quality diamond film by a high power DC arc plasma jet operating in a gas recycling mode

In the present paper, details of a semi-closed gas recycling system incorporated with a high power jet, which allows more than 90% of the feed gas to be recycled while exhausting and feeding a small amount of fresh gas is disclosed. Recent experimental results of diamond deposition by the high power jet system operating in gas recycling mode are presented. The effect of gas recycling on diamond deposition and the quality of the deposited diamond films was discussed. By proper design of the whole system, and optimization of process parameters, thick uniform diamond wafers of Phi 60-100 mm in diameter with a thickness up to 2 mm and transparent diamond wafers of Phi 60 mm in diameter has been deposited successfully. It is demonstrated by the present study that gas recycling can be used even for high quality diamond film synthesis. This is of technical and economical importance in the development of high power DC are plasma jet CVD systems for economical fabrication of large area high quality diamond wafers. (C) 2000 Elsevier Science S.A. All rights reserved.