Dresden 2011 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 85: Poster Session II

HL 85.51: Poster

Donnerstag, 17. März 2011, 18:00–21:00, P4

First Principles Investigation of La incorporation in high-κ Dielectric Film of the Field Effect Transistors — •Ebrahim Nadimi¹, Rolf Öttking², Philipp Plänitz², Martin Trentzsch³, Torben Kelwing³, Rick Carter³, Christian Radehaus², and Michael Schreiber¹ — ¹Institut für Physik, Technische Universität Chemnitz — ²GWT TU Dresden GmbH, Geschäftsstelle Chemnitz — ³Global Foundries, Dresden

The introduction of high-k dielectric and metal gate in silicon field effect transistors (FETs) has involved many challenges. The key requirements are threshold voltage adjustment, reliability of the gate dielectric, low leakage and high channel mobility. Incorporation of metals such as La, Sr, Nb and Mg into thin HfO2 film has been shown to improve the device in terms of threshold voltage, reliability and leakage current. In this work La doping into the HfO2 were investigated on microscopic level using first principles method. Our calculations show that the doped La atoms are energetically favorable when they replace Hf atoms in the first neighboring lattice site of an oxygen vacancy. Furthermore, their interaction with oxygen vacancy leads to the passivation of O-vacancy defect states. Further calculations in multilayer system (Si/SiO2/HfO2) reveal that La atoms tend to migrate into the SiO2/HfO2 interface. This leads to an induced dipole at the interface, which is responsible for the desirable shift in the band alignment. This work was supported by the German ministry of education and research BMBF under SIMKON project Grant No. 01M3138A. The authors are responsible for the content of this paper.