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 VI 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.