Physical model of threshold switching in NbO₂ based memristors

Abstract

This paper investigates the origin of the threshold switching effect in niobium oxide based filamentary switching cells.

Multidimensional Simulation of Threshold Switching in NbO2 Based on an Electric Field Triggered Thermal Runaway Model

“…This combination is under increasing investigation due to its potential to enable fast and highly scalable memory devices. [ 11,13,24 ] In contrast, the intrinsic conductivity change during the phase transition of NbO 2 is slightly lower than a factor of ten as reported by Sakata et al [ 25 ] Therefore, it is questionable if the IMT effect can provide the correct physical explanation of threshold switching observed in the NbO 2 . At this voltage, the resistance changes from a high resistive state (OFF Th ) to a low resistive state (ON Th ).…”

“…It might even be increased by stacking multiple layers of passive matrices to a 3D structure. [7][8][9][10][11][12][13][14][15][16][17][18] Threshold devices show an abrupt resistance change at a certain voltage stress V Th,ON . [ 1,4 ] This serious issue is alleviated by either complementary resistive switching devices or by the integration of a selector device in addition to the passive ReRAM, so called "1S1R" structures.…”

“…[4][5][6] A bipolar switching memristive element requires a bipolar selector device that possesses a highly nonlinear current-voltage ( I-V ) characteristic for both voltage polarities. [ 7,11,21,23 ] Although widely accepted for the explanation of the threshold switching effect, the IMT approach bears two major confl icts. This combination is under increasing investigation due to its potential to enable fast and highly scalable memory devices.…”

“…[7][8][9][10][11][12][13][14][15][16][17][18] Threshold devices show an abrupt resistance change at a certain voltage stress V Th,ON . In the recent works of Slesazeck et al [ 11 ] and Gibson et al [ 10 ] it is shown that the negative slope of the NDR current-voltage characteristics can be reproduced quite nicely by the Poole-Frenkel (PF) conduction mechanism in combination with a moderate Joule heating and an external serial resistance. In contrast to the memristive operation threshold switching is volatile: The resistance state switches to OFF Th as soon as the voltage is reduced below the turn-off voltage V Th,OFF .…”

Heteroepitaxial Growth of T-Nb2O5 on SrTiO3

“…For example, niobium oxides are very attractive for energy storage applications due to their intercalation pseudocapacitance [3,4]. In addition, niobium oxides can be used as selectors or data storage elements in future nonvolatile memory applications [5,6]. The most thermodynamically stable niobium oxide is niobium pentoxide (Nb 2 O 5 ) [1,2].…”