Fabrication of Diffraction Gratings on Aluminum Thin Film Specimens using Focused Ion Beam (FIB)

Different techniques have been used to fabricate diffraction gratings on optical waveguides, switches, and other optical elements. In this research, the Ga+ Focused Ion Beam (FIB) instrument was used to directly write the specimen gratings on the surface of aluminum thin film specimens. The process parameters were optimized and were used to fabricate diffraction gratings.When the Ga ion beam strikes the sample, various particles and radiations are emitted from the sample through the interaction cascade. During this process, there are a number of unwanted phenomena that happen, leading to damage or anomalies in the sample. These damages are in the form of Ga implantation, anomalous Ga phase formation, material redeposition and amorphization, and beam induced grain growth. Since the aluminum films were later used to probe their mechanical properties, the microstructural damage due to the FIB milling has also been studied and the results are presented