Feasibility study of SrRuO3/SrTiO3/SrRuO3 thin film capacitors in DRAM applications
MetadataShow full item record
SubjectSimulation; leakage current; high-k dielectric; feasibility study; Dynamic random access memory (DRAM) cell
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 SrTiO (STO) layer as a dielectric material and SrRuO as electrodes, have been examined. Electrical measurements performed at different temperatures reveal leakage currents that exceed 10. A/cm 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. © 1963-2012 IEEE.
Showing items related by title, author, creator and subject.
Role of defect relaxation for trap-assisted tunneling in high-kappa thin films: A first-principles kinetic Monte Carlo study Jegert G; Popescu D; Lugli P; Haufel MJ; Weinreich W; Kersch A (AMER PHYSICAL SOC, 2012)We assess the impact of structural relaxation of defects upon charging on trap-assisted tunneling in high-kappa dielectric materials. ZrO(2)/Al(2)O(3)/ZrO(2) thin films are taken as an exemplary system. In our completely ...
Popescu B; Popescu D; Saraniti M; Lugli P (Institute of Electrical and Electronics Engineers Inc., 2015)In this paper, we have investigated the electron transport and frequency response of the state-of-the-art single-InAs nanowire (NW) FETs using a full-band Monte Carlo simulator. InAs transistors using a single NW as the ...
Popescu B; Popescu D; Luppina P; Julian T; Koblmüller G; Lugli P; Goodnick S (IEEE, 2015)In this paper, we investigate the electrical and optical properties of novel InGaAs nanowire solar cells. Key features like high optical absorption and excellent charge carrier mobility make them an attractive candidate ...