Effect of annealing conditions on resistive switching in hafnium oxide-based MIM devices for low-power RRAM

Abstract This work presents resistive switching (RS) behaviour in HfO 2 -based low-power resistive random-access memory (RRAM) devices. A metal-insulator-metal (MIM) structure (Au/HfO 2 /Pt) was fabricated by sandwiching a thin insulating layer of HfO 2 between Pt and Au electrodes. HfO 2 films deposited by RF sputtering at room temperature were rapid thermally annealed in N 2 ambient at 400 °C and 500 °C. Grazing angle x-ray diffraction (GIXRD), Field emission gun-scanning electron microscopy (FEG-SEM), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS) were employed to analyse the phase, crystal structure, morphology, surface roughness and chemical composition of the HfO 2 films. The bipolar RS could be observed in both as-deposited and annealed HfO 2 film-based devices from I – V characteristics measured using a source meter. We have investigated the effect of annealing temperature and annealing ambient on the phase formation of HfO 2 as well as the RS characteristics and compared with as-deposited film-based device. Annealed HfO 2 film-based devices exhibited improved electrical characteristics, including stable and repeatable RS at significantly lower switching voltages (<1 V) which indicates low power consumption in these devices. The relatively lower processing temperature of the HfO 2 films and that too in the films deposited by physical vapor deposition (PVD) technique-RF magnetron sputtering makes this study significantly useful for resistive switching based non-volatile memories.