Thermal Engineering of Volatile Switching in PrMnO3 RRAM: Non-Linearity in DC IV Characteristics and Transient Switching Speed

Resistive Random-Access Memory (ReRAM) devices with filamentary and non-filamentary resistive switching (RS) mechanisms are extensively explored for Neuromorphic applications to cater to the present-day dataintensive computing requirements. In filamentary RRAMs, the electric field and Joule heating dependent threshold switching is well established ( Fig. 1a ) [1] . Alternatively, electric-field driven ionic transport was responsible for nonfilamentary memory characteristics ( Fig. 1b ) [2] . In recent studies, self-heating-based mechanism in addition to ionic transport has been suggested in non-filamentary devices ( Fig. 1c ) [3] . This boosts thermally activated ionic drift, thereby enhancing the switching behavior within the device. Different techniques like the incorporation of heater elements or thermally insulating layers such as GST to improve heat confinement within the stack has been proposed to improve device characteristics [4] . Recently, highly non-linear I-V characteristics have been demonstrated in PMO based RRAM in its Low Resistance State (LRS). The PMO material has very low thermal conductivity (0.5W/m-K), which facilitates thermal feedback leading to non-linearity (NL). Further, independent of enhanced RS, two capabilities of PMO-RRAM devices have been demonstrated. Firstly, NL enabled selector-less memory operations, which are highly attractive in crossbar memory arrays ( Fig. 1d ) [5] . Secondly, it facilitates oscillations based on NL related NDR from thermal runaway( Fig. 1e ) [6] , [7] . Thus, investigating & engineering the NL is of significant interest. In this paper, we modify the thermal circuit of the PMO RRAM device stack by changing isolation SiO 2 thickness, keeping the rest of the electronic/ionic aspects of the RRAM structure identical. We show~ 38% reduction in threshold voltage in DC and an 8x improvement in heating transients as a response to thermal circuit engineering.