Structural property investigation on obliquely deposited thick Al films

摘要

As we know, high-quality large-area thick Al films have important applications in echelle gratings. To fabricate them, the deposition angle is one of the most decisive factors. In this study, for the first time we investigate the structural properties of thick Al films deposited by electron beam evaporation at different deposition angles. By measuring film morphology, surface roughness and hardness, we demonstrate the influences of deposition angle on structural properties of thick Al films. A large amount of columnar microstructures and air voids appear in thick Al films with deposition angle increasing, which seriously degrade surface roughness and film hardness. The formation origin of columnar microstructures and air voids is clarified through growth dynamics analysis of Al films. The large deposition angle could significantly reduce the structural properties of Al films. So to attain thick Al films with large-area uniformity and high quality, the deposition angle should be precisely controlled.