Fabrication of high-frequency moiré gratings for microscopic deformation measurement using focused ion beam milling

In this paper, the fabrication technique of high-frequency moiré gratings with a focused ion beam (FIB) is studied thoroughly and comprehensively. The concept is proposed for the first time that the frequency and the size of the grating must be designed to meet the requirements of measurement accuracy and the view field at the same time. Some skills are summarized to get high quality gratings. To check its ability for high temperature use, a grating with a frequency of 2000 lines mm^-1 is fabricated on the amorphous SiC micro-beam. SEM moiré are recorded at room temperature and after high temperature of 350 °C and 550 °C respectively. The fringes are distinct at all stages except for a contrast degradation after high temperature, which demonstrates that SEM moiré combined with the grating fabricated by FIB milling is a promising tool to measure microscopic deformation of micro-device at room temperature and high temperature.