Materials Science in Semiconductor Processing 7 (2004) 231–236 Growth of lanthanum oxide films for application as a gate dielectric in CMOS technology P. Pisecny a,b,Ã , K. Husekova a , K. Frohlich a , L. Harmatha b , J. Soltys a , D. Machajdik a , J.P. Espinos c , M. Jergel d , J. Jakabovic b a Institute of Electrical Engineering, SAS, Du´bravska´ cesta 9, 841 04 Bratislava, Slovak Republic b Faculty of Electrical Engineering and Information Technology, STU, Ilkovicova 3, 812 19 Bratislava, Slovak Republic c Instituto de Ciencia de Materiales de Sevilla, CSIC, Avda. Americo Vespucio s/n., 41092 Sevilla, Spain d Institute of Physics, SAS, Du´bravska´ cesta 9, 845 11 Bratislava, Slovak Republic Available online 12 October 2004 Abstract We have investigated properties of insulating lanthanum oxide (La 2 O 3 ) films in connection with the replacement of silicon oxide (SiO 2 ) gate dielectrics in new generation of CMOS devices. The La 2 O 3 layers were grown using metal organic chemical vapour deposition (MOCVD) at 500 1C. X-ray diffraction analysis revealed polycrystalline character of the films grown above 500 1C. The X-ray photoemission spectroscopy detected lanthanum carbonate as a principal impurity in the films and lanthanum silicate at the interface with silicon. Density of oxide charge, interface trap density, leakage currents and dielectric constant (k) were extracted from the C  V and I  V measurements. Electrical properties, in particular dielectric constant of the MOCVD grown La 2 O 3 are discussed with regard to the film preparation conditions. The as grown film had k  11: Electrical measurements indicate possible presence of oxygen vacancies in oxide layer. The O 2 -annealed La 2 O 3 film had k  17: r 2004 Published by Elsevier Ltd. Keywords: MOCVD; High-k dielectric; Lanthanum oxide; MOS structure 1. Introduction In the present time a lot of research effort is devoted to search for new alternative dielectric materials for CMOS technology. As the dimensions of MOS FET devices are scaled down, materials having higher di- electric constant should replace SiO 2 gate dielectric: high-k materials. Lanthanum oxide, La 2 O 3 , could be considered as a candidate for CMOS gate application, since it has high dielectric constant close to 30 and enough large band gap equal to 4.3 eV [1,2]. However, the La 2 O 3 films were reported to be hygroscopic and unstable in the air, forming carbonate and hydroxide impurities [3,4]. These impurities are harmful for a MOS FET device, since they create charges in the gate dielectric and consequently, result in large flat-band voltage shifts [5]. Thin lanthanum oxide films were already prepared by molecular beam epitaxy [4], vacuum evaporation [6–8], atomic layer deposition (ALD) [4] and by metal organic chemical vapour deposition (MOCVD) [9]. Even though the latter methods (ALD and MOCVD) exhibit enough ARTICLE IN PRESS 1369-8001/$-see front matter r 2004 Published by Elsevier Ltd. doi:10.1016/j.mssp.2004.09.020 Ã Corresponding author. Faculty of Electrical Engineering and Information Technology, Slovak University of Technol- ogy, Ilkovicova 3, 812 19 Bratislava, Slovak. Tel.: +421260291872; fax:+421254775816. E-mail address: pavol.pisecny@stuba.sk (P. Pisecny).