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DF: Dielektrische Festkörper

DF 1: Elektrische und optische Eigenschaften I

DF 1.9: Fachvortrag

Montag, 26. März 2001, 12:50–13:10, S18/19

Ab Initio Band Structures of HfO₂ and PrO₂ — •Victor Zavodinsky¹, Jarek Dabrowski¹, Hans-Joachim Müssig¹, Konstantin Ignatovich¹, and Andrzej Fleszar² — ¹IHP, Im Technologiepark 25, D-15236 Frankfurt (Oder), Germany — ²Institut für Theoretische Physik und Astrophysik der Universität Würzburg, Sanderring 2, D-97070 Würzburg, Germany

Due to their high dielectric constant, ability to grow epitaxially on Si(001) substrates, and compatibility with CMOS technology, praseodymium and hafnium oxides are prospective candidates to substitute SiO₂ in decanano MOSFET transistors [1]. We report first ab initio pseudopotential calculations of band structures, dielectric functions, and electronic excitation energies for these materials. We find that fluorite phases of PrO₂ and HfO₂ have similar electronic structures. The important difference is a narrow subband forming the conduction band bottom in PrO₂ but absent in HfO₂. Electrons in this f-type subband have large masses. This explains why ultrathin epitaxial praseodymium oxide films have low leakage currents in spite of a relatively small conduction band offset (about 1 eV) between the praseodymium oxide and the Si substrate.

[1] H. J. Osten, J. P. Liu, P. Gaworzewski, E. Bugiel, P.Zaumseil, Techn. Dig. IEDM 2000.