Regensburg 2007 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 11: Symposium: New Materials for Nanoelectronics

DS 11.3: Hauptvortrag

Dienstag, 27. März 2007, 10:30–11:00, H32

Rare Earth based amorphous ternary oxide layers as alternative gate dielectrics — •Jürgen Schubert¹, Tassilo Heeg¹, Martin Roeckerath¹, Joao Marcelo Jordao Lopes¹, Uffe Littmark¹, Chao Zhao², Matty Caymax², Valerie Avanasiev³, Lisa Edge⁴, Yunfa Jia⁴, Wei Tian⁴, and Darrell Schlom⁴ — ¹IBN 1-IT and CNI, Forschungszentrum Jülich GmbH, 52425 Jülich — ²IMEC, Kapeldreef 75, B-3001 Leuven, Belgium — ³Department of Physics, University of Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium — ⁴Penn State University, 16802 University Park, Pennsylvania, USA

Rare Earth based oxide thin films are promising candidate materials to replace SiO₂ as a gate dielectric in MOSFETs of the next generation. So far most attention attracted HfO₂ and Hf-containing silicates but they have severe drawbacks such as too low recrystallization temperature (T_cr=600^∘C). Calculations on the thermal stability of ternary oxides in direct contact with silicon were resulted in a number of more appropriate oxides [1]. E.g. GdScO₃ single crystals showed excellent properties which could be reproduced for amorphous films. Permittivity of 22, a bandgap of 5.6 eV, band offsets larger than 2 eV and a good thermal stability (T_cr>900^∘C) could be verified. Furthermore those oxides are not hygroscopic in contrast to most of the binary systems. Another promising system is LaLuO₃ which shows k-values of 32 combined with a high thermal stability (T_cr>900^∘C). Most recent results will be presented and discussed. [1] D.G. Schlom and J. Haeni, MRS Bulletin V. 27, No. 3 (2002)