----------- Dear All, I would like to invite you to attend my preliminary examination. Free cookies and coffee will be served. The details of the exam are given below. Thanks Ankit Jain http://web.ics.purdue.edu/~jain28/<http://web.ics.purdue.edu/%7Ejain28/> -- Venue: BRK 1001 Date: August 27th (Monday) Time: 10:30 AM-12:30PM Title: Fundamental Design Principles of MEMS Actuators for More-than-Moore Applications Abstract: Micro-Electro-Mechanical-Systems (MEMS) are known to create new "More-than-Moore" applications because of their versatile use in diverse fields. Examples include: Classical sensors like pressure sensors, accelerometer, etc., and actuators like RF-MEMS capacitive/ohmic switches and varactors in communication, NEMFET in computation, deformable mirrors and Mirasol displays in optical applications. Commercialization of MEMS actuators, however, has not been as widespread as compared to classical MEMS sensors. This is because of the fundamental problems intrinsic to the physics of MEMS actuation. For example: RF-MEMS capacitive switches suffer from the problem of hard-landing, intrinsic hysteresis of NEMFET puts a fundamental limit on the minimum power dissipation, and travel range of deformable mirrors is fundamentally limited by pull-in instability. In this thesis, we explore the application space of MEMS actuators using modeling and simulations, and provide solutions to the fundamental problems mentioned above. We propose (i) strategies of resistive/capacitive braking to address the problem of hard-landing, (ii) idea of reconfigurable nano-structured electrodes to extend the travel range, (iii) techniques of hysteresis-free sub 60mV/dec operation in NEMFET, and (iv) a new class of electromechanical biosensors named Flexure-FET that utilize nonlinear MEMS actuation to achieve exponentially higher sensitivity towards capture of bio-molecules. We also explored the electromechanical reliability issues related to (i) dielectric charging and creep in RF-MEMS, (ii) NBTI, HCI and creep in NEMFET. In future work, we plan to (i) extend the idea of Flexure-FET to stress based vapor and pH sensor thereby developing new critical-point sensors and (ii) evaluate the prospects of ferroelastic MEMS actuators.