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HL: Halbleiterphysik

HL 40: Grenz- und Oberfl
ächen

HL 40.1: Vortrag

Donnerstag, 27. März 2003, 11:00–11:15, BEY/154

Interface Characterization of the High-k Gate Dielectric Pr₂O₃ — •Hans-Joachim Müssig¹, Jarek Dabrowski¹, and Dieter Schmeisser² — ¹IHP, Im Technologiepark 25, D-15236 Frankfurt (Oder), Germany — ²BTU, Angewandte Physik-Sensorik, Postfach 101344, D-03013 Cottbus, Germany

Pr₂O₃ is currently under consideration as a potential alternative gate dielectric candidate for sub-0.1 µm Complementary Metal Oxide Semiconductor (CMOS) technology. For all thin gate dielectrics, the interface with silicon plays a key role, and in most cases is a dominant factor in determining overall electrical properties. We studied the Pr₂O₃/Si(001) interface by a non-destructive depth profiling using synchrotron radiation photo-electron spectroscopy and ab initio calculations. Our results provide evidence that a chemical reactive interface exists consisting of a mixed Si-Pr oxide such as (Pr₂O₃)_x(SiO₂)_1−x, typically in non-stoichiometric composition. There is no formation of neither an interfacial SiO₂ nor interfacial silicide: all Si-Pr bonds are oxidized and all SiO₄ units dissolve in the Pr oxide. Interfacial silicates like (Pr₂O₃)_x(SiO₂)_1−x are promising high-k dielectric materials because they represent incremental modification of SiO₂ films by Pr ions so that the interface characteristics can be similar to Si-SiO₂ interface properties. Under ultrahigh vacuum conditions, silicide formation is observed when the silicate film is heated above 800^∘C. The praseodymium silicate system observed at the interface between Si(001) and Pr₂O₃ offers greater flexibility towards integration of Pr₂O₃ into future CMOS technologies.