Berlin 2005 – scientific programme

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DS: Dünne Schichten

DS 10: FV-internes Symposium „Anorganische Dielektrika für die künftige Mikro- und Nanotechnologie"

DS 10.1: Invited Talk

Saturday, March 5, 2005, 10:00–10:45, TU HS110

Atomic-scale properties of high-k dielectrics for CMOS: ab initio study for Pr-based materials — •Jarek Dabrowski¹ and Andrzej Fleszar² — ¹IHP, Im Technologiepark 25, 15236 Frankfurt(Oder), Germany — ²Universität Würzburg, Am Hubland, 97074 Würzburg, Germany

In the nearest future, a dielectric with a dielectric constant k several times higher than that of SiO₂ will be needed for the fabrication of CMOS devices. The search for an optimal dielectric is not complete. Numerous metal oxides and silicates are being investigated, various deposition and annealing techniques are being developed which try to utilize the effects attributed to alloying, incorporation of nitrogen, gettering of oxygen, etc. At the same time, the basic knowledge on the microscopic properties of these materials is poor. Ab initio calculations assist in the interpretation of the experimental results and in the choice of the direction of further work.

Using Pr-based dielectrics as a case study, we discuss the atomic and electronic structures of bulk oxides and silicates, of various defects and impurities, and of the interfaces to Si. We consider the native defects (vacancies and self-interstitials), the defects associated with such elements as Si, Ti, Sr, or B, the effect of moisture, and the diffusion of elements and moieties (e.g., of SiO₂ in Pr₂O₃). We describe the interaction between materials during fabrication of a dielectric film, e.g., the formation of electrically active defects in SiO₂ by a Pr layer deposited on top of a SiO₂ layer. Finally, we turn our attention to the formation of the interface between Si(001) and the Pr oxide and/or silicate.