Department of Materials Science and Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
Department of Electrical and Computer Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
ACS Appl Mater Interfaces. 2017 Apr 5;9(13):11704-11710. doi: 10.1021/acsami.6b16559. Epub 2017 Mar 21.
Pulsed and quasi-static current-voltage (I-V) characteristics of threshold switching in TiN/TaO/TiN crossbar devices were measured as a function of stage temperature (200-495 K) and oxygen flow during the deposition of TaO. A comparison of the pulsed and quasi-static characteristics in the high resistance part of the I-V revealed that Joule self-heating significantly affected the current and was a likely source of negative differential resistance (NDR) and thermal runaway. The experimental quasi-static I-V's were simulated using a finite element electro-thermal model that coupled current and heat flow and incorporated an external circuit with an appropriate load resistor. The simulation reproduced the experimental I-V including the OFF-state at low currents and the volatile NDR region. In the NDR region, the simulation predicted spontaneous current constriction forming a small-diameter hot conducting filament with a radius of 250 nm in a 6 μm diameter device.
TiN/TaO/TiN 交叉点器件的阶跃和准静态电流-电压 (I-V) 特性随阶段温度 (200-495 K) 和 TaO 沉积期间的氧气流量而变化。在 I-V 的高电阻部分比较阶跃和准静态特性表明，焦耳自加热显著影响电流，并且可能是负微分电阻 (NDR) 和热失控的来源。使用有限元电热模型模拟了实验准静态 I-V，该模型将电流和热流耦合，并结合了带有适当负载电阻的外部电路。该模拟再现了实验 I-V，包括低电流下的关断状态和易挥发的 NDR 区域。在 NDR 区域，模拟预测自发电流收缩形成一个小直径热传导丝，在一个 6μm 直径的器件中半径为 250nm。
