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Theory

Theory

Objective

SiO2 gate dielectrics in MOS transistors and MIM capacitors have approached the limit of viable thicknesses. To answer some of the key questions appearing in this context one needs insight into atomic processes during dielectric formation and operation. We address these questions by ab initio calculations. Two groups of problems here are of major practical interest: defect chemistry and band structures. Point defects and their complexes are responsible for leakages across the MOS structure, that is, for power losses. They also deteriorate MOSFET parameters, e.g., charged defects shift the threshold voltage and interfacial states reduce the switching speed. These defects must be identified and methods to reduce their concentration must be found. Band gaps and band offsets are the other crucial factor determining the MOS leakage. We address these issues primarily for Pr-based dielectrics (oxides, silicates, and aluminates).  

IHP`s Contribution

Project coordination and total energy calculations.

Funding

Supercomputer time grant from von Neumann Institute for Computing.

Project Partners

  • IHP
  • TU Würzburg

Selected Publications

  • J. Dąbrowski, A. Fleszar, G. Lippert, G. Lupina, A. Mane, H.-J. Müssig, T. Schroeder, R. Sorge, H. Thieme, Ch. Wenger and P. Zaumseil, Atomic-scale properties of high-k dielectrics: ab initio study for Pr-based materials, accepted for publication in Advances of Solid State Physics 2005 (2005).

  • J. Dąbrowski, A. Fleszar, G. Lippert, G. Lupina, A. Mane and Ch. Wenger, Charge traps in high-k dielectrics: ab initio study of defects in Pr-based materials, accepted for publication by Springer Verlag “Topics in Applied Physics” (July 2005).

  • J. Dabrowski, E. R. Weber, H.-J. Müssig, and W. Schröter, Transistors and Atoms, in “Predictive Simulation of Semiconductor Processing – Status and Challenges”, Springer Series in MATERIALS SCIENCE, Chapter 1, Springer-Verlag Berlin, Heidelberg 2004. 
  • J. Dabrowski and V. Zavodinsky, Ab initio study of Pr oxides for CMOS technology to Dielectric Properties of Thin-Films, NIC Series 20, (2004), 171, by John von Neumann Institute for Computing (ISBN 3-00-012372-5).
  • J. Dabrowski and E. R. Weber (Editors), Predictive Simulation of Semiconductor Processing – Status and Challenges, Springer-Verlag Berlin, Heidelberg 2004.  
  • J. Dabrowski, et al., Pseudopotential Study of PrO2 and HfO2 in Fluorite Phase, Microelectronics Reliability 41(7), 1093 (2001).
The building and the infrastructure of the IHP were funded by the European Regional Development Fund of the European Union, funds of the Federal Government and also funds of the Federal State of Brandenburg.