On the Bipolar Resistive Switching Memory Using TiN/Hf/HfO2/Si MIS Structure

TiN/Hf/HfO2/poly-Si structure was employed as the platform to investigate the resistive switching mechanism of metal-insulator-semiconductor (MIS)-based resistive random access memory (RRAM) devices. Based on the presence of a HfSiOx interfacial layer containing a large amount of oxygen vacancy defects, a resistive switching model is proposed to explain the observed bipolar switching behavior which is of opposite operation polarity as compared to metal-insulator-metal (MIM)-based TiN/Hf/HfO2/TiN RRAM devices. The dependence of dopant type/concentration on operation voltage is explained by depletion/accumulation effect of poly-Si bottom electrode. In addition, the MIS-based RRAM devices exhibit good reliability performance in terms of stable dc switching endurance up to 100 cycles and ten-year retention ability at 85 degrees C, with memory window higher and close to 100, respectively. The results suggest that MIS-based RRAM using Hf/HfO2 is a promising alternative for next-generation nonvolatile applications.