NOVEL PVD FILMS BY UNBALANCED MAGNETRON SPUTTERING

The development of the unbalanced magnetron has greatly increased the versatility of the sputtering process. High quality thin films of many types can be deposited more readily than had been possible previously. The ease with which the energies of the depositing atoms can be altered, from low to very high levels, enables the unbalanced magnetron to serve as a powerful research device, as well as being, in many cases, ideal for production systems. The paper highlights the principles of operation of an unbalanced magnetron, and exhibits its versatility by describing two examples of film deposition. The deposition of OFHC copper has enabled the creation of highly dense and ductile fine grained, 'bulk' type films up to 1 mm in thickness, at deposition rates of up to 3-mu-m min-1. It has been shown that for copper, a level of substrate power density of about 0.1 W cm-2 is required to ensure a dense, non-columnar microstructure, for any combination of deposition parameters. The deposition of highly orientated reflective aluminium films onto polished silicon wafers has demonstrated how the unbalanced magnetron could be used to emulate existing and more expensive deposition techniques.