Conventional physical vapour deposition (PVD) techniques usually result in films of lower quality than the corresponding bulk material. A major problem with PVD films is the presence of columns and voids throughout the thickness of the film. The films may have a low packing density, low micro-hardness and in many cases poor adhesion to the substrate. Many of these problems are a direct consequence of the low energy of the depositing atoms arriving at the substrate during film growth. The resulting film porosity gives rise to a reduction in mechanical strength, and in the case of dielectric optical films, a reduction in the refractive index. The properties of deposited films are greatly improved when the substrate or the growing film is bombarded with more energetic particles. An ideal deposition process requires a high flux of film atoms with an energy of approximately 5-50 eV in order to achieve sufficient surface mobility at the substrate to overcome columnar growth. [Continues.]
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.