Diamond-like carbon films prepared by rf substrate biasing in an ECR discharge

Abstract

The optical band gap, density, and hydrogen content of diamond-like carbon films have been controllably varied by rf biasing the substrate in an ECR discharge of pure methane. The optical band gap varied from 2.7 to 1.2 eV, the density from 1.4 to 2.2 g/cm3, and the atomic fraction of hydrogen from 50 to 5%. The range of measured values is in agreement with those predicted by both the random covalent network and defected graphite models.