This dissertation presents a series of studies which explores the use of the structural phase transition of VO2 in MEMS actuators. MEMS actuators enable the interaction of devices with their surroundings, instead of simply sensing it. Actuation mechanisms, which are very common in the macro scale, such as pneumatics, induction motors, and combustion engines, are very difficult and inefficient to implement in the micro scale. Therefore, new actuation techniques must be developed and optimized. Current actuation mechanisms such as electrostatic or thermal expansion have limited performance in terms of total displacement, applied force, operating voltage, and power requirements. This has resulted in a push to incorporate new multifunctional smart materials into standard MEMS devices to improve performance. VO2 has proven to be one of the most promising materials for the creation of new sensors and actuators. Although most of its electrical and optical properties have been thoroughly studied, there is very little work related to its SPT and its application to MEMS actuators. Throughout this dissertation the SPT of VO2 is extensively studied, methods are developed for the optimal design of VO2-based actuators. The memory effect caused by the hysteresis in the SPT is exploited to create very robust programmable multiple state actuators. And fabrication processes are developed which combine the use of VO2 with standard MEMS fabrication processes.
Read
