Effect of process pressure on diamond-like carbon deposited using electroncyclotron resonance chemical vapor deposition

Diamond-like carbon films were deposited using electron cyclotron resonance chemical vapor deposition system under various process pressure conditions . The electron cyclotron resonance plasma was characterized using a Langmui r probe and optical emission spectroscopy. The film properties were charact erized using Raman and Fourier transform infrared spectroscopy, hardness an d optical gap measurements. It was found that the ion density and all peaks in the optical emission spectrum decreased monotonously following the incr ease in process pressure. Raman spectra and optical gap measurements sugges t that the films become more diamond-like and contain a lower sp(2) content following the increase in process pressure. Infrared spectroscopy measurem ents showed a significant increase in hydrogen content as the process press ure increased from 4 to 12 mtorr, and only a slight increase as the pressur e increased from 12 to 20 mtorr. A deposition mechanism is described which involved ion bombardment and hydrogen-surface interactions. The deposition rate is correlated to the ion density and CH3 density. (C) 2001 Elsevier Sc ience B.V. All rights reserved.