April 6, 2012
Hosted by: Columbia Integrated System Laboratory
Speaker: Prof. Saeed Mohammadi , Associate Professor (School of Electrical and Computer Engineering, Purdue University)
Silicon on Insulator (SOI) technology has been widely used for low power analog and digital circuits for applications in mobile computation and communication. An addition of a buried oxide layer beneath a thin Si device layer in SOI technology brings about a new physics to the CMOS transistor, one that is still not fully understood. The buried oxide layer reduces the parasitic capacitance of transistors and interconnect metallizations to the Si substrate, which in turn reduces the dynamic power dissipation. Moreover, the buried oxide layer, when combined with trench oxide, helps electrically isolate CMOS transistors from each other and from the Si substrate. Electrically isolated SOI transistors can be stacked on top of each other to form power amplifiers with large output voltage swings. On the other hand, buried oxide layer facilitates micromachining of thin Silicon Nanowires that can be easily made into suspended double-clamped nanoelectromechanical resonators. With excellent control over the fabrication process, these mechanical resonators are made reliable, reproducible and widely tunable. In addition, they can be excited in their nonlinear dynamics modes including parametric amplification and resonance modes. In this presentation, SOI applications in both power amplifiers and integrated Nanoelectromechanical systems are revisited and our most recent results are presented.
Saeed Mohammadi graduated with a Masters degree in Electrical Engineering from the University of Waterloo, ONT, Canada in 1994. He earned his PhD degree in Electrical Engineering from the University of Michigan in Ann Arbor in 2000. Since 2002, he has been at Purdue University where he currently serves as an Associate Professor. His research interests are in the areas of experimental nanotechnology and RF circuits. Together with his students, Prof Mohammadi has published more than 120 papers in these areas including the first carbon nanotube RF transistor, the first transparent flexible display technology based on carbon nanotube thin film transistors and the first RF CMOS receiver implemented in subthreshold regime.