Effect of annealing on forming-free bipolar resistive switching of Gd2O3 thin films

Abstract

Oxide-based resistive switching devices are a promising candidate for non-volatile memory applications. Here, we present a Gd2O3-based non-volatile memory device deposited using e-beam evaporation. In order to know the effect of annealing on the device performance, the as-grown sample was annealed at 500 °C. The capacitance (C) – voltage (V) and conductance (G) – voltage (V) measurements were investigated in the range of 200 kHz to 1 MHz. It was observed that the C-V and G-V changes with frequency due to the presence of interface states. The effect of series resistance (Rs) and interface state density (Dit) was also investigated for both devices. Furthermore, the resistive switching was recorded at± 5 V. Both devices exhibit bipolar resistive switching with charge conduction mechanism ascribed to ohmic, space charge limited conduction, and trap-filled space charge limited conduction. Consequently, the annealed device displayed an improved resistance ratio of 102 and a stable endurance of up to 1000 cycles with better data retention of over 103 s.