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Enhanced thermal stability of yttrium oxide-based RRAM devices with inhomogeneous Schottky-barrier
2020, Piros, Eszter, Petzold, Stefan, Zintler, Alexander, Kaiser, Nico, Vogel, Tobias, Eilhardt, Robert, Wenger, Christian, Molina-Luna, Leopoldo, Alff, Lambert
This work addresses the thermal stability of bipolar resistive switching in yttrium oxide-based resistive random access memory revealed through the temperature dependence of the DC switching behavior. The operation voltages, current levels, and charge transport mechanisms are investigated at 25 °C, 85 °C, and 125 °C, and show overall good temperature immunity. The set and reset voltages, as well as the device resistance in both the high and low resistive states, are found to scale inversely with increasing temperatures. The Schottky-barrier height was observed to increase from approximately 1.02 eV at 25 °C to approximately 1.35 eV at 125 °C, an uncommon behavior explained by interface phenomena. © 2020 Author(s).
Toward Reliable Compact Modeling of Multilevel 1T-1R RRAM Devices for Neuromorphic Systems
2021, Perez-Bosch Quesada, Emilio, Romero-Zaliz, Rocio, Perez, Eduardo, Kalishettyhalli Mahadevaiah, Mamathamba, Reuben, John, Schubert, Markus Andreas, Jimenez-Molinos, Francisco, Roldan, Juan Bautista, Wenger, Christian
In this work, three different RRAM compact models implemented in Verilog-A are analyzed and evaluated in order to reproduce the multilevel approach based on the switching capability of experimental devices. These models are integrated in 1T-1R cells to control their analog behavior by means of the compliance current imposed by the NMOS select transistor. Four different resistance levels are simulated and assessed with experimental verification to account for their multilevel capability. Further, an Artificial Neural Network study is carried out to evaluate in a real scenario the viability of the multilevel approach under study.
Role of Oxygen Defects in Conductive-Filament Formation in Y2O3-Based Analog RRAM Devices as Revealed by Fluctuation Spectroscopy
2020, Piros, Eszter, Lonsky, Martin, Petzold, Stefan, Zintler, Alexander, Sharath, S.U., Vogel, Tobias, Kaiser, Nico, Eilhardt, Robert, Molina-Luna, Leopoldo, Wenger, Christian, Müller, Jens, Alff, Lambert
Low-frequency noise in Y2O3-based resistive random-access memory devices with analog switching is studied at intermediate resistive states and as a function of dc cycling. A universal 1/fα-type behavior is found, with a frequency exponent of α≈1.2 that is independent of the applied reset voltage or the device resistance and is attributed to the intrinsic abundance of oxygen vacancies unique to the structure of yttria. Remarkably, the noise magnitude in the high resistive state systematically decreases through dc training. This effect is attributed to the stabilization of the conductive filament via the consumption of oxygen vacancies, thus reducing the number of active fluctuators in the vicinity of the filament.