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DF: Fachverband Dielektrische Festkörper
DF 19: Poster 2
DF 19.11: Poster
Mittwoch, 13. März 2013, 15:00–17:30, Poster B2
Oxygen Related Defects and the Reliability of Strained High-κ Dielectric Films in Field Effect Transistors: A First Principles Investigation — •Ebrahim Nadimi1,2,4, Rolf Öttking2, Philipp Plänitz2, Martin Trentzsch3, Christian Radehaus2, and Michael Schreiber1 — 1Institut für Physik, Technische Universität Chemnitz — 2GWT-TUD GmbH Geschäftsstelle Chemnitz — 3Global Foundries, D-01109 Dresden, Germany — 4Faculty of Electrical and Computer Engineering, K.N. Toosi University of Technology, Tehran, Iran
The strain engineering of the silicon channel in metal-oxide-field-effect transistors (MOSFET) along with the high-k (HK) and metal gate (MG) technology has been used in order to improve the performance of these transistors. Applying both techniques raises the question: what would be the interaction of these two techniques. The main concern in HK/MG stacks is the reliability and degradation of the gate dielectric which is mainly related to the oxygen vacancies. In this work we try to study the influence of mechanical stress on the electronic properties of such defects. First principles calculations based on the density functional theory and beyond that (hybrid functionals) were applied to investigate the formation energy and induced trap levels. The calculations reveal that mainly the charged defects are responding to the mechanical stress. In agreement with experimental results which show larger negative bias temperature instability (NBTI) for compressively stressed samples, the calculated formation energy of positively charged defects reduces by compressive stress while it rises with tensile stress.