Design and Simulation of MEMS Actuators to Study Strain Behavior of 2D Materials
Since the 60s the semiconductor industry has successfully been able to keep pace with Moore’s Law due to the effective scaling of the silicon-based transistor. However, as scaling technology improves, passive power density has begun to dominate the overall power consumption of transistors. The inability to scale power density alongside the decreasing transistor dimensions has hindered the efficiency trend observed in the last decades. Thus, new alternatives have been researched to overcome the current power crisis. Micro-electro-mechanical system (MEMS) actuators offer excellent on/off ratios with very steep transitions. Furthermore, two-dimensional transition-metal dichalcogenide (TMD) materials have been studied due to their intrinsic properties, such as their relatively high strength and tunable bandgap resulting from mechanical strain. Semiconducting TMDs can switch between semiconducting to metallic state based on the uniaxial tensile strain they are subjected to. Furthermore, devices which exploit the bandgap tunability of the TMDs to enhance their conductivity have not been thoroughly explored. In this thesis, MEMS comb actuators were designed and simulated to achieve high electrostatic forces to mechanically strain the considerably stiff TMDs. Comb-drive actuators were successfully designed for SOI and SiGe MEMS processes. A strain of 6% is predicted in the MoS2 bilayer at sub-100 Volt operation for both cases. The SOI process has the advantage of a simpler fabrication process and greater stability due to the thicker device layer. On the other hand, the SiGe process has the potential for lower voltage actuation in the vertical direction due to a much thinner oxide layer.
Martinez, Mariana, "Design and Simulation of MEMS Actuators to Study Strain Behavior of 2D Materials" (2018). ETD Collection for University of Texas, El Paso. AAI10931108.