Unveiling processing-structure-property correlations in SiO2-Cr-Au composite thin films from molecular dynamics simulations

Precisely-engineered thin films are essential for many technological applications such as coatings, sensors and semiconductor devices. Since the microstructure of thin films, and thereby, their functionality is shaped by the processing conditions, it is imperative to comprehend the relationship between processing, structure, and the resultant properties. Thin films of chromium and gold are employed in precision accelerometers in autonomous navigation and guidance of missiles and launch vehicles. Performance of these thin films is dependent on the stability of thin films deposited on the non-metallic, highly stable pendulous structure made of fused silica. The purpose of this work is to investigate the connection between thin film processing parameters, microstructural features, and the mechano-thermal properties of Cr-Au thin films deposited on fused silica using Molecular Dynamics (MD) simulations. Simulations mimic the sputtering phenomenon over a range of deposition energies, followed by annealing, to unravel the structural changes, defect features and ensuing properties such as Young's modulus, compressive strength, hardness and coefficient of thermal expansion. We show that moderate deposition energies and lower annealing temperatures are crucial for enhancement in modulus, strength and hardness, while lower deposition energies result in structures possessing larger toughness