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

Hydrogenated amorphous carbon (a-C:H) films have been deposited from acetyl ene gas in a microwave electron cyclotron resonance (ECR) plasma reactor. T he films were deposited at a pressure of 0.2 mTorr and at radio frequency ( r.f.) induced substrate biases from 80-300 V. Selected him properties, incl uding optical bandgap and bonded hydrogen content, were measured. At r.f. i nduced biases from 150 to 300 V, corresponding to ion energies for C2H2+ of approximately 150-300 eV, the hydrogen content remains constant and the op tical bandgap peaks at a bias of 200 V, or approximately 100 eV per carbon in the C2H2+ ions. This ECR system result is in agreement with those observ ed by other researchers using different deposition methods where an optical bandgap maximum and an sp(3) maximum occurs at ion energies of 90-100 eV p er carbon atom. The discharge properties measured include a partial pressur e analysis of the residual exit gas and the substrate current density. (C) 2000 Elsevier Science S.A. All rights reserved.