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In this paper, we have investigated the leakage current versus voltage characteristic of high- k thin film capacitors over a large temperature range. Fabricated samples, consisting of a 10-nm thin {\rm SrTiO}_{3} (STO) layer as a dielectric material and {\rm SrRuO}_{3}$ as electrodes, have been examined. Electrical measurements performed at different temperatures reveal leakage currents that exceed 10^{-7}~{\rm A}/{\rm cm}^{2} at 1 V, a requirement needed for dynamic random access memory (DRAM) applications. We perform a detailed simulation study for the measured samples, making use of a modified drift diffusion model, which also takes into account charge trapping/detrapping effects and nonlocal tunneling. Based on our simulations, we propose an explanation for the large leakage currents observed experimentally. They can be attributed to a trap-assisted tunneling process that is enhanced by oxygen vacancies in the STO dielectric layer. We are thus able to reproduce the temperature and voltage dependence of the measured currents and can use our model to examine the impact of different physical parameters on the behavior of the capacitor structure—a first step toward device optimization. A feasibility analysis is performed for a 1T1C DRAM cell using an optimized deep trench STO capacitor with a reduced oxygen defect density. The simulation results underline the advantages of our modeling procedure using a commercial technology computer aided design (TCAD) framework: once the complex leakage mechanism is implemented, it can be activated on arbitrary 3-D structures, taking advantage of all the postprocessing or visualization capabilities. [ABSTRACT FROM AUTHOR]

Leakage currents in \TiN/\high-\kappa\-ZrO2/ \TiN capacitors were simulated by using a novel kinetic Monte Carlo algorithm specially designed to describe tunneling transport of charge carriers in high-\kappa dielectrics, including defect-assisted transport mechanisms. Comparing simulation results with experimental data, a model for electronic transport was established and validated. Transport was found to be dominated by Poole–Frenkel emission from positively charged bulk trap states at medium voltages and trap-assisted tunneling at high voltages. Information on the conduction band offset at the \TiN/ZrO2 interface as well as on the trap depth was extracted. The model accurately describes the scaling of the leakage current with temperature and with thickness of the dielectric film, and it provides insight into the mutual interdependence of the competing transport mechanisms. [ABSTRACT FROM AUTHOR]