Thermometry of Filamentary RRAM Devices

Abstract

Since thermal effects play a major role in filamentary RRAM devices, we compare the two localized thermometry methods developed for such devices. One method is based on short-pulsed measurements and the other on the measurement of minority-carrier injection from the filament into a semiconductor electrode by thermionic emission. We carried out and compared the measurements on the same functional oxide layer. Both methods indicate that the filament temperature is at least ∼550 K during device operation. Furthermore, comparison between the measured thermal resistance and the thermal simulations of both techniques shows that under the conditions of low forming current compliance (∼10 μA), the filament dimensions are below ∼5 nm. We show that the thermionic emission method is useful for high-resistance (>100 k ) devices operating at low-power conditions (<10 μW), whereas the pulsed thermometry is more suitable for lower resistance devices (<500 k ) operated above 1 μW. The average thermal resistance measured by the pulse technique decreases with applied power. Our simulations indicate that the expansion of the heated zone surrounding the filament can explain the observed reduction in thermal resistance with applied power. The underlying physics of the two methods is discussed.

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.…”

“…[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. [198] Scanning thermal microscopy (SThM) [200,201] is a good candidate for measuring spatially resolved temperature with nanoscale resolution in future work. Experimental measurement of the local temperature in nanoscale devices is extremely challenging.…”

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

“…From the resulting electron contribution, they deduced a filament temperature of up to 1300 K . By additionally performing 3D finite elements simulations, it was shown that these results are only consistent assuming a filament diameter of 1–3 nm . Janousch et al observed an elevated filament temperature by capturing the temperature profile of a lateral µm‐sized Cr‐doped SrTiO 3 ‐based cell using infrared thermal imaging .…”

Recent Advances in Resistive Switching Materials and Devices: From Memories to Memristors

“…These differences can be critical in understanding the underlying mechanism of the imaged devices, or even changes their final functions. Thus, special care should be taken to conduct the imaging experiment, and compromise is necessary between the ideal real [82][83][84][85][86][87][88][89][90][91][92][93][94][95][96][97][98][99][100] device and the sample for imaging.…”