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

Recently, we demonstrated a TiN/TaOx/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/TaOx/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.