Parametric investigation on laser micro-patterned CuAlNi Shape-memory alloy (SMA) bimorph micromirror and its actuation performance

In this work, Shape-memory alloy (SMA)-based micromirrors were fabricated and the actuation was controlled through thermal stimulus. The micromirrors play a significant role in scanning and light deflection in the MEMS field. The SMA micromirrors were developed by coating CuAlNi thin film on strained kapton polyimide substrate using thermal evaporation. Later patterns were made on micromirrors for transmission and reflection of the light beam during actuation. The displacement of each distinct pattern was explored at different voltages ranging from 1 to 3 V through Joule heating technique. The maximum displacement observed was 1.9 mm for deltoid-patterned micromirror at 3 V. The ladder pattern recorded the minimum deflection of 1.1 mm at 3 V. The shape recovery ratio analysis showed that deltoid pattern bimorph had the highest recovery of 1.656. Energy-Dispersive X-ray Spectroscopy (EDS) analysis showed that the composition was maintained after the deposition.