Optimization of an electro-thermally and laterally driven microactuator

 In previous research about thermally and laterally driven microactuators, Guckel et al. proposed a microactuator based on the variable cross sections but the same length of two adjacent beams. Pan and Hsu presented another type of microactuator based on different lengths but the same cross sections of two adjacent beams. Here, a microactuator that combines the traits of those two designs is proposed, optimized, and fabricated. Finite element analysis is performed to obtain the optimal dimensions of the structures when the maximum lateral displacement is achieved. When the air gap is 2 μm, the optimal performance of current design is similar to Guckel's design with optimal dimensions, but it has 65% larger displacement than Pan and Hsu's design at optimal dimensions. For the case of the large air gap beneath the structure (300 μm), the microactuator of current design has more than 25% tip displacement improvement compared to Guckel's or Pan and Hsu's designs. It is also found that the proposed structure is less sensitive to the beam length variations around optimal point no matter in small or large air gap case. Experimental results also verify that the dimension of the air gap affects the thermal boundary condition, so does the performance and optimal architecture of the microactuators.