Unbalanced magnetron ion-assisted deposition and property modification of thin films

Abstract

Unbalanced magnetron (UM-gun) sputtering sources with the unique characteristic of a high deposition rate and concomitant high ion flux represent an exciting new development in ion-assisted deposition of thin films. We have used a UM-gun capable of producing ion current densities up to 5 mA cm−2 (ion flux 3×1016 cm−2 s−1) when operated at a power of 500 W to produce a variety of thin films of amorphous and crystalline materials by varying both the bombarding ion energy in the range 2–100 eV and the ion/atom arrival rate ratio in the range 0.4–10. The great flexibility and usefulness of UM-guns is demonstrated with examples which include (a) hard diamondlike a-C films prepared under very low ion energy (13–16 eV) bombardment which possess a metastable bonding configuration consisting of a mixture of tetrahedral and trigonal coordination that varies with ion energy, (b) hard and wear-resistant TiN films whose electrical and optical properties change dramatically with ion bombardment, and (c) Ni/Cr alloy films showing ion-induced structural modifications.