The effect of N+ ion energy on the properties of ion bombarded plasma polymer films

This work describes the influence of the ion bombardment on the electrical, optical and mechanical properties of polymer films deposited from radio-fr equency plasmas of benzene. Irradiations were conducted using N+ at 5 x 10( 19) ions/m(2), varying the ion energy, E-0, from 0 to 150 keV. Film element al composition was determined by Rutherford backscattering spectroscopy. El ectrical resistivity and hardness were obtained by the two-point probe and nanoindentation technique, respectively. Ultraviolet-visible spectroscopy w as employed to investigate the optical constants of the samples. Etching ra te was determined by exposure of the films to reactive oxygen plasmas. Ion bombardment induced gradual loss of H and increase in C and O concentration s with Eo. As a consequence the electrical, optical and mechanical properti es were drastically affected. Interpretation of these results is proposed i n terms of chain cross-linking and unsaturation. (C) 2001 Elsevier Science B.V. All rights reserved.