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

Zirconium-doped hafnium oxide (HfZrOx) is one of the promising ferroelectric materials for next-generation memory applications. To realize high-performance HfZrOx for next-generation memory applications, the formation of defects in HfZrOx, including oxygen vacancies and interstitials, needs to be optimized, as it can affect the polarization and endurance characteristics of HfZrOx. 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 HfZrOx. HfZrOx films showed different polarization and endurance characteristics depending on the ozone exposure time. HfZrOx 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 HfZrOx. When the ozone exposure time further increased to 4 s, a reduction of polarization was observed in HfZrOx due to the formation of oxygen interstitials and non-ferroelectric monoclinic phases. HfZrOx, with an ozone exposure time of 2.5 s, exhibited the most stable endurance characteristics because of the low initial defect concentration in HfZrOx, 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 HfZrOx films for the improvement of polarization and endurance characteristics.

Automated summary

Zirconium-doped hafnium oxide (HfZrOx) films were studied to investigate the effects of ozone exposure time during the atomic layer deposition (ALD) process on their polarization and endurance characteristics. It was found that HfZrOx with an ozone exposure time of 2.5 s exhibited the most stable endurance characteristics due to its low initial defect concentration, which was confirmed by leakage current analysis. This study highlights the importance of controlling the ozone exposure time in ALD to optimize the formation of defects in HfZrOx films for improved polarization and endurance characteristics.