Hydrogenated amorphous carbon films deposited in an electron cyclotron resonance-chemical vapor deposition discharge reactor using acetylene

摘要

Hydrogenated amorphous carbon (a-C:H) films have been deposited from acetylene gas in a microwave electron cyclotron resonance (ECR) plasma reactor. The films were deposited at a pressure of 0.2 mTorr and at radio frequency (r.f.) induced substrate biases from 80-300 V. Selected film properties, including optical bandgap and bonded hydrogen content, were measured. At r.f. induced biases from 150 to 300 V, corresponding to ion energies for C{sub}2H{sub}2{sup}+ of approximately 150-300 eV, the hydrogen content remains constant and the optical bandgap peaks at a bias of 200 V, or approximately 100 eV per carbon in the C{sub}2H{sub}2{sup}+ ions. This ECR system result is in agreement with those observed by other researchers using different deposition methods where an optical bandgap maximum and an sp{sup}3 maximum occurs at ion energies of 90-100 eV per carbon atom. The discharge properties measured include a partial pressure analysis of the residual exit gas and the substrate current density.