CHARACTERIZATION OF DC UNBALANCED MAGNETRON DEPOSITION OF NI C-H COMPOSITE FILMS/

The process of depositing Me/C: H composite films in an argon/n-hexane gas mixture using a DC unbalanced magnetron was analysed by energy se lective mass spectrometry and microgravimetric techniques. With only a rgon as the working gas the ion mass spectra show contributions typica lly expected from the process gas and sputtered metal. The plasma comp osition changes with n-hexane admixture, resulting in densely packed i on mass spectra from CxHY+ fragments and oligomer ions of higher molec ular mass than the parent molecule. Poisoning of the nickel target is revealed by the time dependent ion current signals. The ion energy dis tribution is dominated by two groups of ions: a low energy peak genera ted by thermalised plasma ions gaining an energy of several eV during transit across a small plasma sheath in front of the grounded discharg e anode, and high energy ions produced either by direct ionisation of high energy neutrals from the sputter process, by elastic collisions w ith the high energy neutrals, or by backscattering of neutralised prim ary ions. The collisional processes require ions with a sufficiently h igh elastic collision cross-section and low dissociation probability. As a result of the influence of the discharge parameters on the ion en ergy distribution, the grounded substrate is bombarded mainly by posit ive CH3+, Ar+ and Ni+ ions with a mean energy of between 2 and 10 eV. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.