Effect of annealing temperature on microstructural evolution and electrical properties of sol-gel processed ZrO2/Si films

Abstract

High-permittivity (k) ZrO2/Si(100) films were fabricated by a sol-gel technique and the microstructural evolution with the annealing temperature (Ta) was correlated with the variation of their electrical performance. With increasing Ta, the ZrO2 films crystallized into a tetragonal (t) phase which was maintained until 700 °C at nanoscale thicknesses. Although the formation of the t-ZrO2 phase obviously enhanced the k value of the ZrO2 dielectric layer, the maximum capacitance in accumulation was decreased by the growth of a low-k interfacial layer (IL) between ZrO2 and Si with increasing Ta. On the other hand, the gate leakage current was remarkably depressed with increasing Ta probably due to the combined effects of the increased IL thickness, optical band gap of ZrO2, and density of ZrO2 and decreased remnant organic components.

Zr4+ Doping in Li4Ti5O12 Anode for Lithium‐Ion Batteries: Open Li+ Diffusion Paths through Structural Imperfection

“…[44] Very interestingly, we could not find any notable change in the Ti 2p spectra, such as evidence of the formation of the Ti 3 + state, with changing Zr content. [45] It should be noted that no prominent change in the binding energy with increasing Zr 4 + doping was detected. The Zr 3d signals (d 5/2 and d 3/2 ) clearly appeared at 181.4 and 183.8 eV for all the Zr-doped LTO samples, indicating that the Zr 4 + has an ionic bonding characteristic.…”

Growth and electrical properties of spin coated ultrathin ZrO2 films on silicon

“…This may be due to the presence of grain boundaries which serve as the predominant leakage current path as the thickness of ZrO 2 films reduced during annealing. 24 The dielectric breakdown measurement is done by measuring the leakage current with the applied voltage. At the breakdown voltage, the leakage current increases sharply.…”

“…Hardy et al 5 also fabricated ZrO 2 ultrathin film (10-30 nm) on SiO 2 /Si substrate by the chemical route and presented the electrical characterization results of the films. Hwang et al 24 also deposited ZrO 2 thin film (7-13 nm) on Si (100) by a sol-gel technique. They studied the microstructural evolution of the films with the annealing temperature and reported the electrical properties of the films also.…”

“…In spite of its advantages like low cost and simplicity, there is very little report on ultrathin ZrO 2 films due to the inherent shortcoming of the sol-gel method. 24 Majority of the previously published literatures discussed about the x-ray photoelectron spectroscopy (XPS) analysis of the ultrathin ZrO 2 film's chemical stability and its interface with Si, 7,10,11,13,21,25,26 which is indeed a very important parameter for MOS applications. But there are very few reports on dielectric quality of the ultrathin ZrO 2 film, 9,11,13,18,26 another equally important parameter.…”

Phase and structural evolution of sol–gel synthesized ZrO2/Si thin films under heat treatment

“…Alternatively, a sol-gel route has advantages such as simplicity and cost-effectiveness in processing, controllability of diverse chemical compositions, and applicability to large-area devices [19]. In our previous research, we examined the phase, microstructure, and dielectric performances of sol-gel processed ZrO 2 thin films for application to high-k dielectrics and demonstrated the stabilization of the nanocrystalline t-phase evolving from the amorphous phase by increasing the film thickness and/or annealing temperature [20]. However, we did not address the phase evolution via chemical state changes from the sol to gel to Zr oxide by heat treatment, which could be essential for modulating the phase formation via process modification or for doping with foreign elements.…”