Improvement of data retention in HfO<inf>2</inf>/Hf 1T1R RRAM cell under low operating current

Abstract

One of the key concerns related to low operating current (<;50μA) of RRAM is the degraded data retention. Most of the retention studies so far focused on high switching current range. In this work, we investigate the retention degradation mechanism at low programming current range (10-40μA) and identify the key parameters that control retention in oxygen vacancy filamentary switching HfO<;sub>2<;/sub>/Hf 1T1R RRAM cells. Based on this understanding we demonstrated significant improvement in retention by adding an additional thermal budget into our process flow. The impact of the Forming process on retention property was also investigated and Forming/SET conditions were optimized to improve the retention without increasing the operation current.