Effects of the electrode materials and operating environment on magnesium fluoride based bipolar RRAMs

Abstract

Emerging memory technologies show the potentials of new memory devices to store more data at a lower cost compared to the industry-standard silicon-based devices. Among these, resistive switching random access memory (RRAM) devices, which are based on the metal-insulator-metal (MIM) structure, have shown potential in non-volatile memory applications due to their characteristics of low-power consumption, superior switching speed, excellent reliability, ultimate scaling potential with the simple fabrication process and adaptive aptitudes for the neuromorphic applications [1, 2]. The advantage of the biodegradable materials is non-toxic and eco-friendly but the essential material properties remain the major issues in the scaling of biomass-based RRAMs [3]. Biodegradable magnesium fluoride (MgFx) is an insulator with a large bandgap (11.3 eV) which makes it a favorable candidate for biodegradable RRAM devices. Recently, a couple of reports on MgFx based RRAM devices have shown excellent resistive switching and biodegradable properties [2, 4]. Nevertheless, the conduction mechanism and resistive switching mechanism in the MgFx based RRAM devices are not fully understood. The electrodes in RRAM devices may significantly affect the resistive switching (RS) behavior. The effects of electrode materials and operating environment including cryogenic temperature on the device performance have not been studied yet. In this study, we report resistive memory devices employing MgFx as the resistive switching layer that is inserted between the platinum and titanium metal electrodes. The MgFx based RRAM devices exhibit electroforming free bipolar resistive switching characteristics at room temperature and open-air environment. We also report the effects of electrode materials (Top: Pt, Au/Ni, ITO, and Bottom: p+ Si, n+ Si, ITO) on MgFx based RRAM devices. It is found that the difference in workfunctions affects the performances of the devices. We have also analyzed the effect of the operating environment as well as temperature from room temperature down to cryogenic temperature. The detailed performance of the devices, their conduction and switching mechanisms, the effects of the electrode materials, and the operating environment including cryogenic temperature will be presented at the virtual conference.