Effect of the bias voltage on the structure of carbon nitride films

The effect of the bias voltage on the structural, optical and mechanical properties of amorphous carbon nitride films deposited by the plasma decomposition of methane (CH4) and nitrogen (N-2) atmosphere is investigated. A series of films was deposited under the condition in which diamond-like, a-C:H, films are obtained, i.e. bias of - 200 V, and pressure of 1.0 Pa. Another series of films was deposited under the condition graphitic-like films is obtained, i.e. bias of - 800 V, and pressures of 12 Pa. In order to investigate the effect of these conditions on the properties of the films, optical, Nano hardness, EELS, and stress measurements were undertaken. It was observed that the incorporation of nitrogen and the investigated properties depend on the starting structure (diamond-like vs. graphitic-like). The use of high gas pressure and high bias allowed the preparation of stable and thick (> 1 micron) nitrogen-carbon films, with high hardness (18 GPa), and low stress (0.5 GPa) deposited at relatively high deposition rate (0.5 nm/s). (C) 2004 Elsevier B.V All rights reserved.