Electrical properties of nanocrystalline HfTiO4 gate insulator

Jaroslaw Domaradzki 2Danuta Kaczmarek 2Agnieszka Borkowska 2Marek Wołcyrz 1Bogdan Paszkiewicz 2

1. Polish Academy of Sciences, Institute of Low Temperature and Structure Research (INTiBS), Okólna 2, Wrocław 50-422, Poland
2. Wrocław University of Technology, Faculty of Microsystem Electronics and Photonics (WEMIF), Janiszewskiego 11/17, Wrocław 50-372, Poland

Abstract

Microelectronics technology needs the use of a stable dielectric thin films for novel metal-oxide-semiconductor (MOS) applications. So far, as a gate insulators the typical dioxides (MO2), where M = Si, Ti, Ru, Hf, have been used. Due to the fabrication of MOS devices, the structures should be characterized by low equivalent oxide thickness (EOT), bellow 1 nm. Such requirement led the need of preparation of either thin film dielectrics with large band offset (HfO2) or very high permittivity (TiO2). In the present work the results of electrical properties of mixed HfxTi1-xO2 solid solution thin films have been presented. The HfTiO4 thin films, were grown on monocrystalline (100) oriented silicon substrates by the low pressure hot target reactive sputtering from the Ti:Hf (46.7:53.3) mosaic target. Appropriate conditions of deposition process assured almost pseudoepitaxial conditions of the layer growth what is testified by the stoichiometric composition of prepared thin films by the XPS investigations. The microstructure of the thin films was verified by X-ray and AFM examinations. The stable HfTiO4 phase with the grain size in the range of few tenths of nanometers and the homogenous distribution of crystallites appeared over the whole sample surface of the thin films being investigated.
Electrical properties of prepared MOS structures were examined by means of C-V and I-V characterization. It have been shown, that the mixture of high-k TiO2 and wide band gap HfO2 dielectrics, gives the reasonable solution for fabrication of the thin films of insulator with intermediate properties.

 

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Presentation: poster at E-MRS Fall Meeting 2005, Symposium F, by Jaroslaw Domaradzki
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-19 09:38
Revised:   2014-10-07 11:54