Research Projects

Thin metallic films deposited on to crystalline substrates grow with specific orientation relationships (ORs). The mostly observed ORs are the ones with low surface energies aligned parallel to substrate surfaces. At higher thicknesses, orientations that minimize the biaxial modulus hence the strain energy preferably form. The ORs mentioned above all depend on the free energies related to the formation and growth of the nuclei. Mechanisms of dislocation plasticity and twinning are not considered extensively in conventional theories on thin film texture formation. Recently, orientations of {115}, {221} and {447}: all related to twinning of {001} and {111} were reported in CoCrFeNi films with intermediate thicknesses of 0.5 – 1 μm. Further consistent formation of a high index orientations such as {345}||(0001) was attributed to twinning. Given the background, there is huge scope for systematic experiments and theories on formation of textures other than {001} and {111} in fcc metallic films with intermediate thicknesses, especially with a reference to dislocation plasticity and twinning. The objective of the proposed study is to aim for obtaining high {hkl} orientations by selecting deposition and material parameters with a high propensity for twinning and dislocation slip. The study aims to start with Co, Ag, Cu and Ni – elements in the increasing order of the stacking fault energy (SFE), and will be extended to selected binary, ternary, quaternary alloys of these elements deposited on oxide substrates. New material variables will be introduced to the theories of thin film OR formation, complementing those existing. Possibility for extension to applications in the future projects includes, for example, CoNi magnetic thin films, Ag and alloy interconnects– both of which are relevant to semiconductor manufacturing. The benefits expected from the proposed projects are many. Firstly, existing gaps of knowledge in the literature would be addressed. Secondly, new areas such as microwave interaction in the paradigm of thin film metallic materials will be introduced. Thirdly, a low cost and reproducible technique, possible extension to future applications direct the group towards developing indigenous high-end technologies without compromise on the primary focus of theoretical aspects. Finally, development of fundamental aspects with an intention of proposing robust theories is naturally expected to result in quality publications.