Dr. Tonya M. Klein
- Associate Professor
Areas of Research
- In‐situ IR Spectroscopy of Thin Film Deposition
- Ph.D., Chemical Engineering, North Carolina State University, 1999
- B.S., Chemical Engineering, University of Florida, 1994
As electronic, magnetic and photonic devices become more sophisticated, there is an ever‐pressing need to fully understand the physics and chemistry of solid interfaces. Technologies such as spin valves, field effect transistors, and nano‐laminate optical coatings are all comprised of ultrathin films in the nanometer thickness regime.
At this dimension, bulk thermodynamic properties governing film stability, diffusion, and reactions as well as bulk electron transport mechanisms that determine device performance no longer apply. Hence, there is a need to develop novel preparation procedures for thin film structures with abrupt interfaces for incorporation in new devices and in test devices, which probe fundamental physical phenomena like electron scattering at interfaces in giant magneto resistance and tunneling magneto resistance recording heads.
Atomic Layer Chemical Vapor Deposition is a promising technique for the fabrication of nanometer scale thin films for alternate high k gate dielectrics in field effect transistors, dielectrics for magnetic tunnel junctions, and metal thin films for spin valves, optical coatings, or diffusion barriers for interconnects. The process involves a separation of the reaction sequence into two self-limiting steps dependent on the availability of functional groups present on the surface. This allows the formation of an atomic layer one step at a time, resulting in excellent film uniformity, conformality and thickness control.
PUBLICATIONS AND PATENTS:
- Li, S. Schafer, R. Datta, T. Mewes, T.M. Klein, A. Gupta, “Microstructural and ferromagnetic resonance properties of epitaxial nickel ferrite films grown by chemical vapor deposition” Applied Physics Letters, 101 (2012) 132409.
- J. Li, L. Zhang, D.A. Dixon, T.M. Klein, “Undulating Topography of HfO2 Thin Films Deposited in a Mesoscale Reactor Using Hafnium (IV) tert Butoxide” AICHE Journal 57 (2011) 2989-2996.
- Li, M. Liu, Z. Zhou, N.X. Sun, D.V.B. Murthy; G. Srinivasan, T.M. Klein; et al. “Electrostatic tuning of ferromagnetic resonance and magnetoelectric interactions in ferrite-piezoelectric heterostructures grown by chemical vapor deposition” Applied Physics Letters 99 (2011) 19.
- J. Li, S.G. Li, N. Li, T.M. Klein, D.A. Dixon, “Tetrakis(ethylmethylamido) Hafnium Adsorption and Reaction on Hydrogen-Terminated Si(100) Surfaces” Journal of Physical Chemistry C, 115 (2011) 18560-18571.
- Li, Y.H.A. Wang, M.N. Illiev, T.M. Klein; A. Gupta, “Growth of Atomically Smooth Epitaxial Nickel Ferrite Films by Direct Liquid Injection CVD.” Chemical Vapor Deposition 17 (2011) 261-269.
HONORS AND AWARDS:
- NSF CAREER Award, 2003
- AIChE Southeast Regional Fellow, 1994-1997
- Florida Academic Scholar, 1989-1994
- Joseph W. Fordyce Scholar, 1989-1991