Defect Engineering of Hafnia-Based Ferroelectric Materials for High-Endurance Memory Applications.

ABSTRACT: Zirconium-doped hafnium oxide (HfZrO_x) is one of the promising ferroelectric materials for next-generation memory applications. To realize high-performance HfZrO_x for next-generation memory applications, the formation of defects in HfZrO_x, including oxygen vacancies and interstitials, needs to be optimized, as it can affect the polarization and endurance characteristics of HfZrO_x. In this study, we investigated the effects of ozone exposure time during the atomic layer deposition (ALD) process on the polarization and endurance characteristics of 16-nm-thick HfZrO_x. HfZrO_x films showed different polarization and endurance characteristics depending on the ozone exposure time. HfZrO_x deposited using the ozone exposure time of 1 s showed small polarization and large defect concentration. The increase of the ozone exposure time to 2.5 s could reduce the defect concentration and improve the polarization characteristics of HfZrO_x. When the ozone exposure time further increased to 4 s, a reduction of polarization was observed in HfZrO_x due to the formation of oxygen interstitials and non-ferroelectric monoclinic phases. HfZrO_x, with an ozone exposure time of 2.5 s, exhibited the most stable endurance characteristics because of the low initial defect concentration in HfZrO_x, which was confirmed by the leakage current analysis. This study shows that the ozone exposure time of ALD needs to be controlled to optimize the formation of defects in HfZrO_x films for the improvement of polarization and endurance characteristics.

SUBMITTER: Kim MK 

PROVIDER: S-EPMC10210041 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature