Dear All:

I would like to invite you for my PhD defense examination. The details are given below-

Thanks
Regards,
Ankit

Date: July 30th, 2014
Venue: Birck 1001
Time: 2-4PM

Title:

Fundamental Design Principles of Novel MEMS based "Landau" Switches, Sensors, and Actuators : Role of Electrode Geometry and Operation Regime

Abstract:

Microelectromechanical systems (MEMS) are considered as potential candidates for "More-Moore" and "More-than-Moore" applications due to their versatile use as sensors, switches, and actuators. Examples include: Accelerometers for sensing, RF-MEMS capacitive switches in communication, suspended-gate (SG) FET in computation, and deformable mirrors in optics. In spite of the wide range of applications of MEMS in diverse fields, one of the major roadblocks for MEMS is their instability. Instability divides the operation regime into stable and unstable and poses fundamental challenges for several applications. For example: Tuning range of deformable mirrors is fundamentally limited by pull-in instability, RF MEMS capacitive switches suffer from the problem of hard landing, and intrinsic hysteresis of SG-FET puts a lower bound on the minimum power dissipation.  

In this thesis, we provide solutions to the application specific problems of MEMS and utilize operation in or close to unstable regime for performance enhancement in several novel applications. Specifically: (i) We propose novel device concepts with nanostructured electrodes to address the aforementioned problems of instability, (ii) We propose a switch with hysteresis-free ideal switching characteristics based on the operation in unstable regime, and (iii) We propose a Flexure biosensor that operates at the boundary of stable and unstable regimes to achieve improved sensitivity and signal-to-noise ratio. In general, we have advocated electrode geometry as a design variable for MEMS and used MEMS as an illustrative example of "Landau" systems to advocate operation regime as a new design variable.