Filamentary Resistive Switching and Capacitance-Voltage Characteristics of the a-IGZO/TiO2 Memory

In this study, molybdenum tungsten/amorphous InGaZnO (a-IGZO)/TiO2/n-type Si-based resistive random access memory (ReRAM) is manufactured. After deposition of the a-IGZO, annealing was performed at 200, 300, 400, and 500 degrees C for approximately 1h in order to analyze the effect of temperature change on the ReRAM after post annealing in a furnace. As a result of measuring the current-voltage curve, the a-IGZO/TiO2-based ReRAM annealed at 400 degrees C reached compliance current in a low-resistance state, and showed the most complete hysteresis curve. In the a-IGZO layer annealed at 400 degrees C, the O-1/O-total value increased most significantly, to approximately 78.2%, and the O-3/O-total value decreased the most, to approximately 2.6%. As a result, the a-IGZO/TiO2-based ReRAM annealed at 400 degrees C reduced conductivity and prevented an increase in leakage current caused by oxygen vacancies with sufficient recovery of the metal-oxygen bond. Scanning electron microscopy analysis revealed that the a-IGZO surface showed hillocks at a high post annealing temperature of 500 degrees C, which greatly increased the surface roughness and caused the surface area performance to deteriorate. Finally, as a result of measuring the capacitance-voltage curve in the a-IGZO/TiO2-based ReRAM in the range of -2V to 4V, the accumulation capacitance value of the ReRAM annealed at 400 degrees C increased most in a nonvolatile behavior.