Dr. Yi-Chia Chou is a Professor in the Department of Materials Science and Engineering at National Taiwan University. She received her B.Sc. degree in Materials Science and Engineering from National Tsing Hua University at Hsinchu, Taiwan and Ph.D. degree from University of California Los Angeles in CA, USA. She was a visiting student at Lawrence Berkeley Laboratory with support of a fellowship. Her postdoc research was at IBM Thomas J. Watson Research Center and was appointed as a guest scientist at Brookhaven National Laboratory. Before joining NTU, she was a professor in the Department of Electrophysics at National Yang Ming Chiao Tung University.
Her research interests focus on fundamental understanding of materials science including the reactions in semiconductors, the growth of semiconductor nanostructures, and the microstructure and defect in high entropy alloys analyzed using high performance transmission electron microscopy.
She was a recipient of UCLA Graduate Fellowship in 2006, a recipient of Dissertation Fellowship Award in 2010, and a recipient of TSMC Outstanding Graduate Student Award in 2010. For her achievement at postdoc research on investigation of the growth of Si/Ge heterojunction nanowires with alloy catalysts using in situ UHV-TEM and Cs-corrected ETEM, she was awarded Presidential Postdoctoral Award from Microscopy Society of America in 2012. She was awarded as Taiwan Promising Women in Science in 2019, IBM Faculty Award in 2017, and Ministry of Science and Technology (MOST) Young Scholar Fellowship-Columbus Project (2018-2023), for her career in Taiwan.
Many electronic devices, such as field-effect transistors, depend on achieving precise control of both a semiconductor nanostructure and its contact with the larger scale circuit. The control of the contact between nanowire and circuit is a key step that involves integrating different types of materials and bridging between length scales. In Si nanowires, we show that silicide formation can occur through a point contact reaction and we demonstrate that the reaction shows different kinetics from those already known in thin film silicide technology. We discuss the strain effect on the nucleation and growth of silicides in nanowires with thermodynamic, kinetic, and strain energy implications. Such nanowires have an oxidized surface and this controls the reaction pathway and kinetics. To follow up the present model, the gradient of stress potential is treated as the driving force for “uphill diffusion” of metal atoms in Si to migrate to the epitaxial interface. Additionally, the strain effect is taken as a reason that an extremely high degree of supersaturation of Ni, over a factor of 1000 needed for NiSi formation, can take place near the interface. The need of an extremely high super-saturation, about a factor of 1000, of Ni interstitials for the nucleation is because of the extremely low equilibrium solubility of Ni in Si. Also what is the diameter of the point contact is irrelevant, provided that it is not closed to stop the reaction.