Journal of Physics and Chemistry of Solids 69 (2008) 685–687 Chemical vapor deposition and characterization of hafnium oxide films T.P. Smirnova a,b,Ã , L.V. Yakovkina a,b , V.N. Kitchai a,b , V.V. Kaichev c , Yu.V. Shubin a , N.B. Morozova a , K.V. Zherikova a a Nikolaev Institute of Inorganic Chemistry, Siberian Division, Russian Academy of Sciences, Lavrent’ev ave., 3, Novosibirsk 630090, Russia b Tomsk State University, Lenin ave., 36, Tomsk 634050, Russia c Boreskov Institute of Catalysis, Siberian Division, Russian Academy of Sciences, Lavrent’ev ave., 5, Novosibirsk 630090, Russia Abstract HfO 2 layers were grown on silicon by metalorganic chemical vapor deposition using (C 5 H 5 ) 2 Hf(CH 3 ) 2 , (C 5 H 5 ) 2 Hf(N(C 2 H 5 ) 2 ) 2 and Hf(dpm) 4 as volatile precursors and were characterized by IR, XP, ED-spectroscopy, X-ray diffraction, ellipsometry and electrophysical methods. The films were shown to consist of monoclinic HfO 2 and to contain hafnium silicide and silicate at the HfO 2 /Si interface. The presence of hafnium silicide was attributed to oxygen deficiency induced by argon ion sputtering of the film during XPS analysis. Hafnium silicate was formed as a result of the reaction between hafnia and silicon oxides during annealing. Current–voltage and capacitance–voltage measurements on Al/HfO 2 /Si test structures were used to determine the dielectric permittivity and electrical resistivity of the films: k ¼ 15–20, r ¼ 10 15 O cm. r 2007 Elsevier Ltd. All rights reserved. Keywords: A. Oxides; A. Thin films; B. Vapour deposition; C. Photoelectron spectroscopy 1. Introduction Since advances in the technology of SiO 2 /Si transistors are approaching their limit, further development of information storage and transfer systems is highly depen- dent on the engineering of novel materials with high dielectric permittivity, capable of replacing SiO 2 in the next generation of giga- and tera-bit memory devices. Metal oxides, such as TiO 2 , Ta 2 O 5 , ZrO 2 and HfO 2 , are potentially attractive as gate insulators in silicon transis- tors. Of particular interest are HfO 2 layers, which offer a high dielectric constant k ¼ 25, large band gap E g ¼ 5.68 eV and high thermodynamic stability of their interface with silicon. Although considerable research effort has been concentrated on the synthesis of high- permittivity layers, no commercially viable, reproducible process has been proposed to date. HfO 2 layers can be synthesized using a wide range of precursors: chlorides [1], nitrates [2], alkoxides [3], b-diketonates [4] and amino complexes [5]. Very attractive precursors are cyclopenta- dienyl derivatives of Hf 4+ and hafnium b-diketonate, which have high saturated vapor pressure. Hafnium b- diketonates are more stable and require no special storage conditions. The aim of this work was to deposit hafnia layers by metalorganic chemical vapor deposition (MOCVD) using dipivaloilmethanate hafnium(IV), Hf(dpm) 4 ; dicyclopenta- dienyl hafnium dimethyl, (C 5 H 5 ) 2 Hf(CH 3 ) 2 and cyclopen- tadienyl hafnium bisdiethylamide, (C 5 H 5 ) 2 Hf(N(C 2 H 5 ) 2 ) 2 , as precursors and to examine the relationship between the structure of the precursor and the chemical composition, crystal structure and electrical properties of the films. 2. Experimental HfO 2 films about 100 nm in thickness were grown in the quartz reactor schematized in Fig. 1. The volatile precursor (P) was placed in a boat, which was then mounted in the reactor together with the substrate (S). Two heating elements (T 1 , T 2 ) enabled independent control over the evaporation source and substrate temperatures. As substrates, we used (1 0 0) silicon wafers. Precursor vapors ARTICLE IN PRESS www.elsevier.com/locate/jpcs 0022-3697/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.jpcs.2007.07.123 Ã Corresponding author. Nikolaev Institute of Inorganic Chemistry, Siberian Division, Russian Academy of Sciences, Lavrent’ev ave., 3, Novosibirsk 630090, Russia.