Characterization upon electrical hysteresis and thermal diffusion of TiAl 3 O x dielectric film

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Characterization upon electrical hysteresis and thermal diffusion of TiAl3Ox dielectric film Lei Shi1* and Zhiguo Liu2

Abstract In this paper, we have investigated the electrical properties of TiAl3Ox film as electrical gate insulator deposited by pulsed laser deposition and presented a simple method to describe the thermal diffusion behaviors of metal atoms at TiAl3Ox/Si interfacial region in detail. The TiAl3Ox films show obvious electrical hysteresis by the capacitancevoltage measurements after post-annealing treatment. By virtue of the diffusion models composed of TiAl3Ox film and silicon, the diffusion coefficient and the diffusion activation energy of the Ti and Al atoms are extracted. It is valuable to further investigate the pseudobinary oxide system in practice. PACS: 77.55.-g; 81.15.Fg; 81.40.Gh. Keywords: electrical hysteresis, thermal diffusion, pulsed laser deposition

Introduction High electrical permittivity (k) insulators are presently investigated as possible replacements of SiO 2 or SiON film gate dielectric in order to hurdle the increased tunneling leakage current while the devices are further scaled down. Although a huge number of single-phase high-k materials have been investigated, there is no suitable material that could completely replace the traditional SiO2 as gate dielectrics [1-4]. It is exciting that the recent researches have been concentrated upon the pseudobinary oxides mostly. This section focuses on all these candidates in an attempt to combine and complement the desirable properties from different materials, and then overcome the deficiencies associated with the individual material. Furthermore, the criteria for possible replacement dielectrics require that those materials are chemically stable on silicon substrates at high temperature as well. In fact, most of these potential candidates might partially react with silicon substrates at the interface after thermal treatment, and thus cause an increase of leakage current and degrade devices performance with high-k gate dielectrics [5,6]. As for a potential candidate, it is very important to pursue a small interfacial reaction for a

* Correspondence: [email protected] 1 Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, PR China Full list of author information is available at the end of the article

perfect gate dielectrical candidate, except the preferable electrical properties. In our earlier research, the electrical properties have shown that the TiO2-incorporated Al2O3 film may be a potential replacement as gate dielectrics because of its high dielectric constant, low leakage current, low charge density, etc. [7]. Nevertheless, the interfacial reaction between the film and silicon substrate has been observed, despite of the improved device performance. The interfacial thickness, along with the leakage current, rises rapidly with the increase of the annealing temperature. This is very damaging for high-k gate material