In this thesis a method to control the deposition process of D.C. magnetron
sputtered magnetic thin films is described. A biased anode, situated in
front of the magnetron, is used to alter the plasma characteristics which
influence the film deposition process. The magnetic field configuration
which results from biasing the anode leads to self-biasing at the
film-substrate location. Control of this film self-bias voltage allows for
controlled ion bombardment of the substrate.
The technique is investigated using Cobalt as the target material. With the
given experimental configuration, self-bias voltages up to -40 V at the
substrate location could be achieved. It is demonstrated that the use of
self-bias and ensuing ion bombardment, during film growth at the substrate,
influence the micro-structure and properties of the deposited films.
The micro-crystalline structure and coercivity of magnetron sputtered Cobalt
films exhibited considerable variation with film self-bias. For increasing
self-bias, the film coercivity attained a maximum value then decreased
toward a value less than that of the unbiased case. It is found that the
maximum value of coercivity coincides with the maximum film particle
diameter. The films are found to consist essentially of single-domain
particles, which are responsible for the observed magnetic properties of the
A Masters Thesis. Submitted in partial fulfilment of the requirements for the award of Master of Philosophy of Loughborough University.