Browsing by Author "Tseng, Chih-Yang"

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Gamma-Ray Irradiation Effect on Ferroelectric Devices with Hafnium Aluminum Oxides
(2019-12-01)
Liu, Chien
;
Tung, Yi-Chun
;
Wu, Tian-Li
;
Cheng, Chun-Hu
;
Tseng, Chih-Yang
Herein, the gamma-ray irradiation effect on ferroelectric HfAlO(x)capacitors for biomedical and space applications is investigated. The experimental results focus on the observation of ferroelectric polarization characteristics in support of different defect mechanisms induced by annealing, endurance cycling, and gamma-ray irradiation. It is found that the HfAlO(x)with low Al doping of 6.5% become more vulnerable to radiation exposure, but a remarkable improvement in 9%-Al-doped HfAlO(x)due to less oxygen vacancies is demonstrated. In addition, the results also confirm that the fatigue property of ferroelectric HfAlO(x)capacitor is determined by the electric-stress-induced defect during endurance cycling, not mainly contributed by irradiation damage, which shows the potential for memory applications in rigorous irradiation environment.
Investigation of Polarization Hysteresis and Transient Current Switching in Ferroelectric Aluminum-Doped Hafnium Oxides
(2018-01-01)
Liu, Chien
;
Fan, Chia-Chi
;
Tseng, Chih-Yang
;
Hsu, Hsiao-Hsuan
;
Cheng, Chun-Hu
In this work, we investigated ferroelectric and antiferroelectric effects in ferroelectric HfAIO capacitor with various aluminum doping concentrations. With the increase of aluminum doping concentration, the transition from ferroelectric to weak anti-ferroelectric properties can be observed by measuring polarization hysteresis and transient current response. The experimental results prove that the aluminum doping concentration of HfAIO material not only affects the ferroelectric-antiferroelectric transition, but also determine the leakage issue during domain switching.
Stabilizing Ferroelectric Domain Switching of Hafnium Aluminum Oxide Using Metal Nitride Electrode Engineering
(2019-09-17)
Liu, Chien
;
Tung, Yi-Chun
;
Tseng, Chih-Yang
;
Wang, Wei-Chun
;
Chen, Hsuan-Han
In this work, we comprehensively investigated the metal-electrode stress engineering on HfAlO metal-ferroelectric-metal capacitor. According to experimental results, we confirm that high-nitrogen tantalum-nitride electrode with good chemical stability not only mitigates the anti-ferroelectric property and gate leakage current, but also improves the wake-up effect and endurance cycling characteristics, which shows the great potential for future applications of low-power ferroelectric memories. (c) 2019 The Electrochemical Society.