Investigation of the Impact of High Temperatures on the Switching Kinetics of Redox‐Based Resistive Switching Cells using a High‐Speed Nanoheater

Abstract

Ionic transport greatly influences the switching kinetics of filamentary resistive switching memories and depends strongly on temperature and electric fields. To separate the impact of both parameters on the switching kinetics and to further deepen the understanding of the influence of local Joule heating, a nanometer‐sized heating structure is employed. It consists of a 100 nm wide Pt electrode which, due to Joule heating, serves as heating source upon an electrical stimulus. These self‐heating properties are underlined by a 3D finite elements simulation model, which confirms a temperature increase of almost 500 K. Experimental electrical pulse measurements indicate that for this temperature a steady state is achieved in less than 100 ns. By employing this heating structure, kinetic measurements of a Pt/Ta2O5/Ta cell are performed at different temperatures and reveal that significantly decreased SET times are obtained with increasing temperature. This effect is accompanied by an increasing slope of the current prior to the SET event. The experimental results are further confirmed by predictions of an analytical model based on ionic conduction.

Recommended Methods to Study Resistive Switching Devices

“…[1] Several unique structures have been used to evaluate the local temperature in resistive memory devices, [196][197][198] and ultrafast transient electrical measurements were proposed to study an effective device temperature. Understanding heat and energy dissipation is crucial for the evaluation and design of devices (see also Section 4: simulation of RS), since most proposed switching mechanisms rely on thermally activated processes such as defect generation, ionic transport, etc.…”

The ultimate switching speed limit of redox-based resistive switching devices

“…For example, it has been demonstrated that the non-linearity of the switching kinetics in lamentary switching VCM cells originates from the temperatureaccelerated dri of the ionic defects. [21][22][23][24][25][26] In AgI-based ECM cells, the strong nonlinearity of the switching kinetics results from the nucleation of the conducting lament at the inert electrode at low voltages, the redox reactions at the metal/insulator interfaces at intermediate voltages and ion migration at very high voltages. 27 Also for other ECM systems these processes have been identied as rate-limiting.…”

“…[20][21][22] Higher local temperatures will lead to faster switching speed. According to eqn (19), the value of the effective thermal resistance is the design parameter of choice.…”

Picosecond multilevel resistive switching in tantalum oxide thin films

“…This small current, however, increases the local temperature, which in turn increases the electrical conductivity. This results in a thermal runaway leading to an abrupt SET transition 19,20 . During the RESET Joule heating also occurs, and the oxygen vacancies drift away from the active electrode (high work function metal).…”