The impact of ultraviolet light on the switching characteristics of NiO resistive random-access memory (ReRAM) devices

Abstract

In recent years many research groups have delved into the research and development of Resistive Random-Access Memory (ReRAM) which has the combined advantages of fast read/write speed, simplicity in structure, small device size and density, low activation bias voltage, low power consumption, allowably many periodic operating cycles and nonvolatile memory feature. In order to operate RRAM in an ultraviolet (UV) spectroscopic regime, the spectral transparency of electrodes and reliable device performance are keys to ensuring its continual applicability. Among the materials considered, nickel oxide (NiO) potentially has a broad perspective in optical applications due to their relatively wide bandgap, high mobility, high transparency, remarkably good electrical and optical characteristics. It is foreseeable in the future that the unique applicability of RRAM in UV will make its headway as a key component in many optoelectronic displaying products. The present study focuses on using Radio Frequency Magnetron Sputtering method to prepare NiO active layer and indium tin oxide (ITO) top electrode for the realization of RRAM devices and their current-voltage (I-V) and capacitance-voltage (C-V) characteristics are subsequently evaluated with and without the irradiation of ultraviolet light. Specifically, a series of reliability tests show that the fabricated memories have endured up to 100 switching cycles and the current contrast ratio between high (HRS) and low (LRS) resistance state at 0.1V has achieved more than two orders of magnitude. Furthermore, the retention time measurement has also demonstrated that the memory storage capability of these RRAMs remains in excellent operating condition after surviving more than 10,000 seconds of the test. Major attention is concentrated on finding out a correlation between the UV responsivity and switching characteristics for NiO RRAMs biased at low voltage. We found that the memory states associated with the RRAM of the smallest feature sizes could be toggled relatively easily by UV irradiation at the smallest size.