Composite metal/C:H films prepared in an unbalanced magnetron

Films of the composition of Ag/C:H, Ni/C:H and Mo/C:H have been deposited onto substrates using an unbalanced planar magnetron. The metal was sputtered and the C:H phase was formed via plasma polymerization processes from the n-hexane in the residual atmosphere. The energy to drive this comes from positive ion bombardment of the vapour (n-hexane molecules and their fragments) present on the growing film surface. The ions are accelerated through the potential difference between that of the plasma and that of the surface. This negative bias appears on the growing film surface as a result of the immersion of it in the plasma leaked from the magnetron. Additional bias could be created using an rf potential. The ageing of these films was investigated in terms of their electrical resistance. The ageing effects decrease with increasing values of the negative bias during deposition. For those composites deposited without bias the ageing effects were greatest, with Ag demonstrating the fastest effect which became slower going to Ni and then to Mo. (C) 1997 Elsevier Science Ltd. All rights reserved.