Properties of carbon films by dc plasma deposition

Abstract

Perfectly smooth transparent carbon films deposit onto room-temperature silicon wafers in a dc plasma of methane (CH4) and hydrogen (H2). Transmission electron microscope analysis reveals that the films consist primarily of amorphous carbon (a-C). The nearest neighbor C–C bond length of a-C formed at low discharge current densities or low working pressures approaches that of diamond. Electrical resistivity, calculated using V-I curves for the Al-C-Si structure, is more than 1013 Ω cm. A face-centered-cubic phase with a lattice constant of 4.96 Å and diamond, both of which form at relatively high pressures, consist of crystallites having a diameter of about 100 Å.