GROWTH AND CHARACTERIZATION OF NANOSTRUCTURED THIN FILMS FOR SWITCHING APPLICATIONS

Abstract

Non-volatile memory technology plays a important role in the market of electronics products. Until now, Flash memory dominates the market of non-volatile memories, which is based on traditional floating gate concept. With rapid scaling of microelectronic technology, it has encountered serious technical challenges. To overcome these challenges Resistive Random Access Memory (ReRAM) is a promising candidate for next generation of non-volatile memory. In the present study c-axis oriented Pulsed Laser Deposited Ag/MgxZn1-xO/Cu//Si structure was investigated for its Resistive switching behaviour. The presence of (002) and (103) MgxZn1-xO peaks without any impurity phases in X-ray diffraction confirms the presence of sharp and abrupt interface formation between MgxZn1-xO 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 ~ 3V magnitude. The durability of Non-Volatile Memory nature of the heterostructure was also examined by Keithely 4200 using the ± 4V voltages applied in closed loops. The Resistive Switching behaviour present in the MgxZn1-xO thin film was explained by formation and rupture of the nano-scale conduction filament due to Oxygen vacancies. The leakage analysis revealed the dominance of Ohmic conduction in LRS region and Poole Frenkel emission in HRS region. Improvement in resistive switching behaviour is observed by substitution of Mg in ZnO thin film. Such a Silicon integrated low voltage tuned MgxZn1-xO thin film having non volatile two resistance states could prove useful in future power efficient memory devices.