GROWTH AND CHARACTERIZATION OF NANO-STRUCTURED THIN FILM FOR SWITCHING APPLICATION

Abstract

In the present study c-axis oriented DC sputter Deposited Cu/TiO2/Pt/Si structure was investigated for its Resistive switching behaviour. The presence of (101) anatase TiO2 peaks without any impurity phases in X-ray diffraction confirms the presence of sharp and abrupt interface formation between TiO2 and the electrode layers. The cross sectional FE-SEM studies were further carried out to examine the quality of the interface. The room temperature I-V characteristic of the thin films was conducted using Keithley 4200-SCS (Semiconductor characterization system) to analyze the resistive switching mechanism. I-V characterization of the thin films revealed the bipolar nature of resistive switching and presence of two resistance states i.e. High Resistance (HR) and Low Resistance (LR) which can be switched at relatively low voltage ~ 2V magnitude. The durability of Non-Volatile Memory nature of the heterostructure was also examined by Keithely 4200 using the ± 3V voltages applied in closed loops. The Resistive Switching behavior present in the TiO2 thin film was explained by formation and rupture of the nano-scale conduction filament due to Cu metallic ions. The leakage analysis revealed the dominance of Ohmic conduction in LRS region and SCLC emission in HRS region. Improvement in resistive switching behaviour is observed by adding a thin layer of AlN in the cell structure. The cell also exhibited multilevel switching. Such silicon integrated low voltage tuned TiO2/AlN bilayer thin films having non volatile multiple resistance states could prove useful in future power efficient memory devices.