title: Electro-Thermal Model of Threshold Switching in TaOx-Based Devices.
abstract: Pulsed and quasi-static current-voltage (I-V) characteristics of threshold switching in TiN/TaOx/TiN crossbar devices were measured as a function of stage temperature (200-495 K) and oxygen flow during the deposition of TaOx. 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.
authors.affiliation: Department of Materials Science and Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Jonathan M
authors.identifier: http://orcid.org/0000-0002-3466-3350
authors.initials: JM
authors.lastname: Goodwill
authors.affiliation: Department of Electrical and Computer Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Abhishek A
authors.initials: AA
authors.lastname: Sharma
authors.affiliation: Department of Materials Science and Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Dasheng
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Electrical and Computer Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: James A
authors.initials: JA
authors.lastname: Bain
authors.affiliation: Department of Materials Science and Engineering, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
authors.forename: Marek
authors.identifier: http://orcid.org/0000-0002-2087-0068
authors.initials: M
authors.lastname: Skowronski
keywords: Poole−Frenkel conduction; negative differential resistance; tantalum oxide; thermal runaway; threshold switch