Monolithic Silicon Nanowires: Technology and Device Integration Aspects
Prof. Erdem Alaca, Koç University
Date: Tuesday, January 17, 2017
Si nanowires have been shown to impart significant operational enhancement to microelectromechanical systems (MEMS) as piezoresistive building blocks. Their use is especially promising in next-generation, miniature and low-power sensor platforms for physical and biological applications. However, the need for anchoring suspended nanowires to the surrounding microscale architecture with a two-order-of-magnitude scale difference poses significant integration challenges. Assembly rate, interface quality and alignment accuracy are current issues tackled for the successful batch production. In this talk, a monolithic technology is introduced addressing the shortcomings of available integration techniques. Thanks to a combination of a two-stage etch process with a suitable protection technology the silicon nanowire is patterned and generated, while the surrounding microscale architecture is formed within the same silicon crystal through deep reactive ion etching. The technique inherently assures registration between nano and microscale components. In principle, any combination of patterning techniques including mix-and-match lithography can be utilized within the scope of the proposed approach. As nanowires are fabricated at the wafer surface – as opposed to lying underneath the thick MEMS layer, the technique also allows carrying out surface processes such as contact formation and doping. The implications of the technique are discussed in the case of both passive (double-anchored) and active (MEMS-integrated) devices. Characterization results of the associated mechanical and piezoresistive behavior are presented.
B. Erdem Alaca received the B.S. degree in mechanical engineering from Boğaziçi University, Istanbul, Turkey, in 1997, and the M.S. and Ph.D. degrees in mechanical engineering from the University of Illinois at Urbana–Champaign in 1999 and 2003, respectively. He is currently an Associate Professor in the Department of Mechanical Engineering at Koç University, where he manages Mechanical Characterization and Microfabrication facilities. His research interests include small-scale mechanical behavior, fabrication technologies and precision instruments based on nanoelectromechanical devices. Prof. Alaca is a member of the Turkish National Committee on Theoretical and Applied Mechanics and the Institute of Electrical and Electronics Engineers (IEEE). He was a recipient of the 2009 Distinguished Young Scientist Award from the Turkish Academy of Sciences.