Abstract
In this thesis, we have investigated the resistive switching characteristics of HfO2 thin film in Pt/Ti/HfO2/TiN capacitor structure. The 10-nm-thick HfO2 films are deposited on TiN/Ti/SiO2/Si substrate by atomic layer deposition (ALD), which can well control the film thickness precisely with high uniformity. The Pt top electrode and Ti inter layer are prepared by DC sputtering. The Pt/Ti/HfO2/TiN capacitors show distinct bipolar resistive switching characteristics, which the bipolar polarity would reverse during operation, with the change of Ti thickness. According to post-metal annealing effect at different temperatures, dependence of cell area on resistance state, material analysis, and electrical characteristics, it is tried to build up a model to elucidate the phenomenon of polarity reverse. In an addition, an improvement of resistive switching stability of HfO2-based memory can be achieved by using the Ti reactive interlayer, including good switching endurance and high temperature retention.