Reduction of stress induced bending in MEMS suspended membrane

MEMS suspended membrane is used as moveable mirror in tunable Fabry-Pérot (FP) filters and tunable Lasers. Since the electrical and optical properties of the FP filters and VSCELs are highly dependent on the parallelism of the suspension holding the membrane in place, therefore, it has crucial role in the performance of these devices. Any bending in the suspensions results in displacement of the membrane which, in turn adversely affects the output properties of these devices. In our research work we present a multilayer suspension design with the aim to produce bend-less suspensions by compensating the stress of the materials and balancing the clock wise and counter clock wise moments within the multilayered structure. This new approach enables us to successfully reduce the displacement of the membrane to 76.7nm from several micrometer.