Structural and Electrical Properties of TiO2/HfO2 Superlattices on c-Al2O3 and Si Substrates
Y.H. Tu1*, J.W. Chou1, P.V. Wadekar1, W.C. Hsieh1, W.C. Sung1, C.F. Chang1, H.J. Chen1, H.C. Huang1, Y.P. Cheng1, C.M. Shiau1, Y.S. Hong1, P.C. Kung1, C.Y. Dang1, C.H. Lee1, L.W. Tu1, N.J. Ho1, W.K.Chu2, H.W. Seo3, Q.Y. Chen1,2
1Department of Physics, National Sun-Yat Sen University, Kaohsiung, Taiwan
2Department of Physics and Texas Center for Superconductivity, University of Houston, Houston, USA
3Department of Physics, Jeju National University, Jeju, Korea
* presenting author:Yi-Hsien Tu,
Finding oxides with high dielectric constants is crucial as metal oxide semiconductor field effect transistors (MOSFET) are scaled down to nanometer levels. Two of the best studied high-k dielectric oxides are oxides are rutile titanium dioxide (TiO2) and monoclinic hafnium dioxide (HfO2). In order to investigate the effects of superlattice structure on the dielectric and structural properties, we have grown and characterize superlattices of these materials on c-Al2O3 as well as silicon substrates. The superlattices have been grown using magnetron sputtering at elevated temperatures while structural analysis using X-ray diffraction (XRD) and X-ray reflectivity (XRR) and transmission electron microscopy (TEM) have been used to investigate the structural properties of these samples. Furthermore, these structures have also been integrated on doped Si wafers in the form of metal-insulator semiconductor (MIS) devices. Capacitance-voltage measurements have been done to extract the dielectric constants.

Keywords: superlattices, MIS devices, high-k