Robustly Stable Ferroelectric Polarization States Enable Long-Term Nonvolatile Storage against Radiation in HfO2-Based Ferroelectric Field-Effect Transistors

Siwei Dai; Qijun Yang; Binjian Zeng; Shuaizhi Zheng; Xiangli Zhong; Jinjuan Xiang; Jianfeng Gao; Jie Zhao; Jiajia Liao; Min Liao; Yichun Zhou

doi:10.1021/acsami.2c13392

Robustly Stable Ferroelectric Polarization States Enable Long-Term Nonvolatile Storage against Radiation in HfO₂-Based Ferroelectric Field-Effect Transistors

ACS Appl Mater Interfaces. 2022 Nov 16;14(45):51459-51467. doi: 10.1021/acsami.2c13392. Epub 2022 Nov 1.

Authors

Siwei Dai^{1

2}, Qijun Yang³, Binjian Zeng³, Shuaizhi Zheng³, Xiangli Zhong³, Jinjuan Xiang⁴, Jianfeng Gao⁴, Jie Zhao⁴, Jiajia Liao^{1

2}, Min Liao^{1

2}, Yichun Zhou^{1

2}

Affiliations

¹ School of Advanced Materials and Nanotechnology, Xidian University, Xi'an710126, China.
² Frontier Research Center of Thin Films and Coatings for Device Applications, Academy of Advanced Interdisciplinary Research, Xidian University, Xian710126, China.
³ Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, School of Materials Science and Engineering, Xiangtan University, Xiangtan411105, China.
⁴ Integrated Circuit Advanced Process R&D Center and Institute of Microelectronics of Chinese Academy of Sciences, Beijing100029, China.

PMID: 36318591
DOI: 10.1021/acsami.2c13392

Abstract

The ferroelectric field-effect transistors (FeFETs) with HfO₂-based ferroelectric layers in the gate stacks are emerging as one of the most promising candidates for the next-generation nonvolatile memory devices due to their scalability and compatibility with conventional Si technology. Moreover, owing to the high radiation hardness of the HfO₂-based ferroelectric thin films, HfO₂-based FeFETs have attracted great interest in the fields of radiation-hard (rad-hard) memory. However, the reliability of their memory states under irradiation, which represents the validity of the stored information, has not been investigated. Here, we focus on the impact of the total ionizing dose (TID) on erased and programmed states of HfO₂-based FeFETs. The TID radiation (X-ray) characteristics of erased and programmed HfO₂-based FeFETs are characterized using an on-site read operation. Both the erased and programmed states show robust stability under irradiation at a dose rate of 90 rad(Si)/s, and even at 230 rad(Si)/s, only the erased state shows a slight variation. The possible factors contributing to memory state degradation are discussed. Through the analysis of the threshold voltage shift and subthreshold swing evolution, as well as studies of ferroelectric polarization stability under radiation, it is revealed that the erased state degradation is caused by oxide-trapped charges rather than interface degradation or polarization switching. The physical mechanism of the difference in radiation-induced oxide-trapped charges buildup in programmed and erased FeFETs is analyzed to explain different TID radiation characteristics between them. Our work suggests that the HfO₂-based FeFETs have great potential in radiation environment applications.

Keywords: HfO2-based ferroelectric thin film; ferroelectric field-effect transistor; polarization states; programmed/erased states; total ionizing dose effect.