Designing Wake‐Up Free Ferroelectric Capacitors Based on the HfO2/ZrO2 Superlattice Structure. (25th October 2022)

• Record Type: Journal Article
• Authors: Bai, Na; Xue, Kan‐Hao; Huang, Jinhai; Yuan, Jun‐Hui; Wang, Wenlin; Mao, Ge‐Qi; Zou, Lanqing; Yang, Shengxin; Lu, Hong; Sun, Huajun; Miao, Xiangshui
• Is Part Of: Advanced Electronic Materials. Volume 9:Number 1(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-25
• Subjects: ferroelectric capacitors -- Hf 0.5Zr 0.5O2 -- Pt/ZrO 2 interfaces -- rapid thermal annealing -- wake‐up free; Materials -- Electric properties -- Periodicals; Materials science -- Periodicals; Magnetic materials -- Periodicals; Electronic apparatus and appliances -- Periodicals; 537
• DOI: 10.1002/aelm.202200737
• Languages: English
• ISSNs: 2199-160X

Abstract

Abstract: The wake‐up phenomenon widely exists in hafnia‐based ferroelectric capacitors, which causes device parameter variation over time. Crystallization at a higher temperature has been reported to be effective in eliminating wake‐up, but high temperature may yield the monoclinic phase or generate more oxygen vacancies. In this work, a unidirectional annealing method is proposed for the crystallization of Hf0.5 Zr0.5 O2 (HZO) superlattice ferroelectrics, which involves heating from the Pt/ZrO2 interface side. It is demonstrated that 600 °C annealing only leads to a moderate content of monoclinic phase in HZO, and the TiN/HZO/Pt capacitor exhibits wake‐up free nature and a switchable remnant polarization value of 27.4 µC cm −2 . On the other hand, heating from the TiN/HfO2 side, or using 500 °C annealing temperature, could yield ferroelectric devices that require a wake‐up process. The special configuration of Pt/ZrO2 is verified by comparative studies with several other superlattice structures and HZO solid‐state solutions. It is discovered that heating from the Pt/HfO2 side at 600 °C leads to high leakage current and a memristor behavior. The mechanisms of ferroelectric phase stabilization and memristor formation have been discussed. The unidirectional heating method can also be useful for other hafnia‐based ferroelectric devices. Abstract : Wake‐up free Hf0.5 Zr0.5 O2 (HZO) device is achieved through a delicate capacitor design together with a new annealing method. A unidirectional annealing method is proposed for the crystallization of HZO superlattice ferroelectrics, which involves heating from the Pt/ZrO2 interface side. The unidirectional heating is of potential value to optimize the ferroelectric crystallization in hafnia‐based ferroelectric capacitors.