GROWTH-RATE STUDIES OF CVD DIAMOND IN AN RF PLASMA TORCH

This paper addresses the complex chemistry in the boundary layer over a substrate in a chemical vapor deposition rector at atmospheric press ure. In this study, a highspeed plasma (140 m/s) was created using a r adio-frequency inductively coupled plasma torch for the deposition of diamond thin films. Growth rates on the order of 50 mu m/h were obtain ed for well-faceted continuous films grown on molybdenum substrates po sitioned nor mal to the plasma flow. The highest growth rates were obt ained at substrate temperatures of 1370 K and a feed gas ratio of 2.5% CH4 in H-2. Growth rates are compared to predicted results obtained f rom numerical simulations, based on a one-dimensional stagnation-point flow, and are found to be in good agreement. Several other surface an alysis techniques were used to characterize the deposited films, inclu ding SEM, Raman spectroscopy, transmission electron microscopy, Ruther ford backscattering spectroscopy, and hydrogen-forward recoil spectros copy. Optical emission spectroscopy was used to characterize the RF pl asma during the deposition process. Results from these studies form an important database for the validation and improvement of current mode ls of the atmospheric-pressure diamond CVD environment.