Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 35: Poster Session I (Metal, semiconductor and oxide substrates: structure and adsorbates; Graphene)
O 35.61: Poster
Tuesday, March 12, 2013, 18:15–21:45, Poster B1
Themal stability of thin HfO2 films and structure determination of HfSi2 islands on Si(110) surfaces. — •Frank Schönbohm1,2, Tobias Lühr1, Dominique Handshak1, Lothar Brosda1, Ulf Berges1,2, and Carsten Westphal1,2 — 1Fakultät Physik - Technische Universität Dortmund, Otto-Hahn-Str. 4, D 44221 Dortmund, Germany — 2DELTA - Technische Universität Dortmund, Maria-Goeppert-Mayer-Str. 2, D 44227 Dortmund, Germany
Thin SiO2 gate dielectrics in MOSFETs lose their efficiency because of an increasing leakage current when their thickness is reduced below 2 nm. A possible way omitting this problem is substituting the SiO2 gate dielectric by another material with a higher dielectric constant. Perspective replacement candidates among the so called high-k materials are the oxides of hafnium and zirconium. However, their thermal stability at elevated temperatures is important during the production process. Due to the recent interest in the Si(110) surface orientation we studied thin HfO2 films on Si(110). Photoelectron spectra of Si 2p, Hf 4f, and O 2s signal as a function of annealing temperature were recorded in oder to investigate the thermal stability of the system. The thin HfO2 films are stable up to 730∘C and form HfSi2 under further annealing at 770∘C. Further investigations showed that HfSi2 is arranged in islands at the surface. The HfSi2 islands were investigated by means of photoelectron diffraction (XPD) in order to examine their structure. We present the XPD diffraction pattern and the structure model of the HfSi2 islands which was obtained by computer simulations.