MSE Seminar Series: Katayun Barmak
Friday, September 25, 2015
1:00 p.m.-2:00 p.m.
Room 2108, Chemical and Nuclear Engineering Building
Grain Boundary and Surface Scattering of Electrons in Metals for Deeply-Scaled Interconnects
Philips Electronics Professor
Department of Applied Physics and Applied Mathematics
The classical resistivity size effect, wherein conductors with dimensions on the order of the mean free path of electrons (39 nm for Cu at room temperature) exhibit higher resistivity than bulk conductors, was first noted by Thompson in 1901. The importance of the resistivity size effect to Cu interconnects was first identified by Chen and Gardner of Intel in 1998 and has been of concern to the semiconductor community since then. Over the past 100 years, a number of models that take into account surface scattering, grain boundary scattering and the effect of surface roughness have been proposed to explain the size effect. The talk addresses the classical resistivity size effect in interconnect metals and presents our work on understanding and quantifying the contributions of grain boundary and surface scattering to the observed resistivity increase. Experimental studies of both Cu and W films will be described, including the development of improved metrology techniques for nanoscale metals characterization that employ crystal orientation mapping in the transmission electron microscope. The extent to which semiclassical models of surface and grain boundary scattering mechanisms can be used to describe the experimental results will also be discussed.
About the Speaker
Katayun Barmak obtained her B.A. (First Class Honours) and M.A. degrees in Natural Sciences, Metallurgy and Materials Science from the University of Cambridge, England in 1983. She completed her M.S. in Metallurgy and Ph.D. in Materials Science at the Massachusetts Institute of Technology in 1985 and 1989, respectively. During her doctoral work she was a recipient of an AT&T Foundation Fellowship. Prior to her appointment to the Faculty at Lehigh University in 1992, she spent three years at IBM T. J. Watson Research Center and IBM East Fishkill development laboratory working on materials, structures and processes for field effect and bipolar junction transistors. She joined the Department of Materials Science and Engineering at Carnegie Mellon University in 1999 and was promoted to the rank of Full Professor in 2002. She received the National Young Investigator (NYI) award in 1994 and the Creativity Award in 2001, both from the National Science Foundation. She was a Meeting Chair for the Spring 1999 meeting of the Materials Research Society (MRS) and served as a member of the MRS Council from 1998-2000. She co-edited and authored three chapters in a book on Metallic Films to be appear in 2014. Barmak joined Columbia University in 2011 as the Philips Electronics Chair of Applied Physics and Applied Mathematics, and Materials Science and Engineering.