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Professor Katayun Barmak Professor of Materials Science and Engineering Ph.D., Massachusetts Institute of Technology Department of Materials Science and Engineering Carnegie Mellon University 5000 Forbes Avenue Roberts Engineering Hall 143 Pittsburgh, PA 15213 Email: Phone: (412) 268-4380 Fax: (412) 268-3113

Biography

Dr. Katayun Barmak obtained her B.A. (First Class Hons.) and M.A. degrees in Natural Sciences, Metallurgy and Materials Science from the University of Cambridge, England in 1983 and 1987, respectively. 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 in 1992, Dr. Barmak spent three years at IBM T.J. Watson Research Center and IBM East Fishkill development laboratory working on materials, structures and processes for advanced generations of 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. Dr. Barmak received the National Young Investigator in 1994 and a Deutscheforschunggemeinschaft Fellowship the same year. She was one of four Technical Chairs of the Materials Research Society Meeting in Spring 1999. She was a Visiting Scientist at the IBM T. J. Watson Research Center 1998-2004. She is an Associate Editor of the Journal of Electronic Materials.

Research Interests

Professor Barmak’s research addresses the relationship of processing and structure (crystal structure and microstructure) to electrical and magnetic properties of metal films. Metal films play an important role in the advance of many modern technologies such as integrated circuits, information storage systems, displays, sensors and coatings. They also provide model systems for the study of phenomena that are not easily accessible in bulk systems.

Barmak is a member of the Materials Research Science and Engineering Center and aims to develop a transmission electron microscopy based automated orientation imaging technique that can be applied to the study of nanostructured materials. Her group has been an internationally recognized group in the use of differential scanning calorimetry for the study solid state reactions and phase transformations in thin films.

Phase Transformations

The engineering of phase transformations continues to be key to successful implementation of metals and alloys in micro/nanoscale structures. Whether the promotion or inhibition of a solid state reaction or phase transformation is the desired end for a given application, the quantification of the associated kinetics (e.g., rate) and thermodynamics (e.g., enthalpy) allows for a deeper fundamental understanding and, in principle, more rapid engineering of the transformation. We are a leading group in the use of conventional differential scanning calorimetry for the study of phase transformations in a broad range of technological and model thin film systems.

Microstructure

The microstructure of polycrystalline systems is known to have a profound effect on their electrical and magnetic properties, and therefore quantitative stereological analysis of microstructures is important. Proper characterization includes information not only about the size, shape and orientation of constituent grains, but also the geometry and crystallography of the associated grain boundaries. In addition to experimental studies of thin film microstructures, it is of interest to develop predictive models of microstructure evolution that address nucleation and growth to coalescence followed by grain growth (coarsening). Our aim is for these models to incorporate experimentally measured materials properties, such as grain boundary energy and mobility, and for the simulated microstructures to be validated against experimentally characterized microstructures. To this end, the statistical properties of simulated grain structures are compared with those for experimental grain structures; the latter obtained via semi-automated and automated techniques developed in our laboratory.

Techniques

For the study of thin film phase transformations and microstructures, we use a wide variety of experimental processing and characterization techniques such as sputter deposition, electrodeposition, microfabrication, differential scanning calorimetry, conventional and synchrotron x-ray diffraction for phase identification and texture analysis, scanning and transmission electron microscopy and orientation imaging microscopy. Close collaborations with industry and national laboratories give students access to expertise, instrumentation and techniques not available in our laboratory.

Integrated circuit technology nodes below 100 nm require careful engineering of metals used as interconnections, as contacts to the source, drain and gate of the metal oxide semiconductor field effect transistor (MOSFTET), etc. The engineering of these metal components requires detailed understanding of the evolution of microstructure and/or the mechanisms and paths of solid state reactions and transformations at the nanoscale. The impact of surfaces and grain boundaries on properties and performance of these nanoscale metals is also of great importance. The materials of interest include Al, Cu and Cu alloys, silicides and aluminides. The images show grain growth in Cu films.

Recent Publications

T. Sun, B. Yao, A. Warren, V. Kumar, S. Roberts, K. Barmak, and K. R. Coffey, “Classical size effect in oxide-encapsulated Cu thin films: Impact of grain boundaries versus surfaces on resistivity”, J. Vac. Sci. Technol. A 26, 605-609 (2008).

D. C. Berry, K. Barmak, “Time-temperature-transformation diagrams for the A1 to L1 0 phase transformation in FePt and FeCuPt thin films”, J. Appl. Phys. 101, 014905-1:14 (2007).

(Critical Review) K. Barmak, C. Cabral, Jr., J. M. E. Harper, K. P. Rodbell, “On the use of alloying elements for Cu interconnect applications”, J. Vac. Sci. Technol. B 24, 2485-2498 (2006).

K. Barmak, W. E. Archibald, J. Kim. C.-S. Kim, A. D. Rollett, G. S. Rohrer, S. Ta’asan, D. Kinderlehrer, “Grain boundary energy and grain growth in highly-textured Al films and foils: Experiment and Simulation”, Materials Science Forum495-497, 1255-1260 (2005).

K. Barmak, A. Gungor, A. D. Rollett, C. Cabral, Jr., and J. M. E. Harper, “Texture of Cu and dilute binary Cu-alloy films: Impact of annealing and solute content”, Mater. Sci. in Semicon. Processing 6, 175-184 (2003).