Carbon transition efficiency and process cost in high-rate, large-area deposition of diamond films by DC arc plasma jet

A new DC plasma torch in which are jet states and deposition parameters can be regulated over a wide range has been built. It showed advantages in pro ducing stable plasma conditions at a small gas flow rate. Plasma jets with and without magnetically rotated arcs could be generated. With straight are jet deposition, diamond films could be formed at a rate of 39 mu m/h on Mo substrates of Phi 25 mm, and the conversion rate of carbon in CH4 to diamo nd was less than 3%. Under magnetically rotated conditions, diamond films c ould be deposited uniformly in a range of Phi 40 mm at 30 mu m/h, with a qu ite low total gas flow rate and high carbon conversion rate of over 11%. Me chanisms of rapid and uniform deposition of diamond films with low gas cons umption and high carbon transition efficiency are discussed. (C) 2000 Elsev ier Science S.A. All rights reserved.