Optimization of TiN/TaOx/HfO2/TiN RRAM Arrays for Improved Switching and Data Retention

Recently, we demonstrated a TiN/TaO_x/HfO₂/TiN RRAM [1]. The Conductive Metal Oxide (TaOx) acted as an in-built current compliance layer and improved thermal efficiency too, leading to high-quality RRAM characteristics [1]. In this work, we report excellent resistance uniformity and endurance for these TiN/TaO_x/HfO₂/TiN RRAMs and present techniques to optimize switching and data retention. An oxygen anneal after HfO₂ atomic layer deposition is shown to improve data retention quite significantly for 1kb arrays, while not having a deleterious effect on switching. Experiments on different HfO₂ thicknesses indicate that an optimal thickness exists which gives a good tradeoff between FORM voltage and data retention.