Browsing by Author "Chen, Hsuan-Han"

Now showing 1 - 9 of 9

Ferroelectric Characterization of Hafnium-Oxide-Based Ferroelectric Memories with Remote Nitrogen Plasma Treatments
(2019-01-01)
Lee, You-Ting
;
Chen, Hsuan-Han
;
Tung, Yi-Chun
;
Shih, Bing-Yang
;
Hsiung, Szu-Yen
In this paper, we experimentally demonstrated the advantage of remote nitrogen plasma on improving interface quality of HfO2-based ferroelectric devices. The remote nitrogen plasma not only reduces leakage current of gate stack to appropriately sustain the ferroelectricity during ferroelectric domain switching, but also effectively improve the ferroelectric fatigue to enhance endurance cycling performance.
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.
High performance negative capacitance field-effect transistor featuring low off-state current, high on/off current ratio, and steep sub-60 mV dec(-1) swing
(2020-04-01)
Liu, Chien
;
Chen, Hsuan-Han
;
Tung, Yi-Chun
;
Wang, Wei-Chun
;
Huang, Zhong-Ying
In this work, we demonstrated that the 5-nm-thick HfAlOx negative capacitance transistor (NCFET) with optimized Al doping can achieve a minimum 33 mV dec(-1) subthreshold swing (SS), an ultralow l(off) of 7.44 fA mu m(-1), and a high l(on)//l(off) ratio of 1.9 x 10(8). The NC switching with sub-60 mV dec(-1) SS can be implemented from V-DS - 0.2 V to 0.8 V due to an ultralow off-state leakage current. The experimental results reveal that well-controlled Al doping in HfAlOx not only reduces off-state leakage of the transistor, but also improves the ferroelectric NC effect to achieve a sub-60 mV dec-1 switching under a favorably low sub-1 voltage. This scaled HfAlOx NCFET with optimized Al doping and fluorine defect passivation shows the great potential for the application of low power logic devices. (C) 2020 The Japan Society of Applied Physics
Improved Thermal Stability and Stress Immunity in Highly Scalable Junctionless FETs Using Enhanced-Depletion Channels
(2018-12-05)
Liu, Chien
;
Cheng, Chun-Hu
;
Lin, Ming-Huei
;
Shih, Yi-Jia
;
Hung, Yu-Wen
In this work, we report a novel multi-PNPN-channel junctionless transistor with short channel length of 60nm. The multi-PNPN junctionless transistor exhibits the larger drive current of > 1 mu A/mu m, the steeper turn-on switching of 77 mV/decade, and the higher on/off current ratio of > 10(7) than the hybrid PN channel device under the same gate overdrive. The improved performance is mainly attributed to the enhanced depletion effect of multi-PNPN channel to optimize the electric field modification of surface p-channel. The stronger immunity to constant-voltage stress is also obtained for multi-PNPN channel due to the lower lateral electric field near drain side to reduce the impact ionization ratio. (C) 2018 The Electrochemical Society.
Investigation of Gate-Stress Engineering in Negative Capacitance FETs Using Ferroelectric Hafnium Aluminum Oxides
(2019-02-01)
Cheng, Chun-Hu
;
Fan, Chia-Chi
;
Liu, Chien
;
Hsu, Hsiao-Hsuan
;
Chen, Hsuan-Han
In this paper, we reported a ferroelectric HfAlOx negative capacitor transistor with gate-stress (GS) engineering. Compared to control device, the HfAlOx transistor with GS engineering percentage of I-ON enhancement and 27% V-T reduction under the assistance of the negative capacitance (NC) effect. The orthorhombic phase transition played a crucial role in realizing the NC effect. From the results of the material analysis, the theoretical Landau simulation and electrical measurement, we demonstrated that the GS is favorable for inducing orthorhombic phase crystallization of HfAlOx and stabilizing the NC effect, which shows the potential for the application of advanced technology node.
Investigation of Phase Transformation in HfO2 Ferroelectric Capacitor by Means of a ZrO2 Capping Layer
(2019-01-01)
Liu, Kuan-Wei
;
Chen, Hsuan-Han
;
Huang, Zhong-Ying
;
Wang, Wei-Chun
;
Fan, Yu-Chi
In this paper, the ferroelectric polarization effect of ZrO2 capping layer on HfO2 NUM capacitor was investigated. Based on crystallinity analysis, the phase transformation from monoclinic to orthorhombic phase in HfO2 film can be induced by a thin ZrO2 capping layer. The thickness of ZrO2 capping layer plays an important role in the ferroelectric polarization of HfO2 MFM capacitor. Compared to mixed HfZrO film, the stacked ZrO2/HfO2 film shows the advantage for suppressing the leakage issue during high-temperature ferroelectric phase transition.
Investigation on polarization characteristics of ferroelectric memories with thermally stable hafnium aluminum oxides
(2019-08-01)
Chang, Tun-Jen
;
Liu, Chien
;
Fan, Chia-Chi
;
Hsu, Hsiao-Hsuan
;
Chen, Hsuan-Han
In this work, we successfully demonstrated the 9.6-nm-thick HfAlOx ferroelectric memory using light aluminium doping of 6.5% to form ferroelectric orthorhombic phase. Compared to ferroelectric HfZrOx film with zirconium diffusion issue, the HfAlOx film showed excellent thermal stability under high temperature annealing. Besides, the ferroelectric HfAlOx also exhibited robust polarization characteristics under endurance cycling test. A > 10(6) stressed cycles with 4 MV/cm can be measured and a long endurance was sustained over 5 x 10(7) cycles under 3.6 MV/cm. Therefore, the HfAlOx film showed the great promise for integrating in high performance ferroelectric memory with thermal budget concerns.
Negative Capacitance CMOS Field-Effect Transistors with Non-Hysteretic Steep Sub-60mV/dec Swing and Defect-Passivated Multidomain Switching
(2019-01-01)
Liu, Chien
;
Chen, Hsuan-Han
;
Hsu, Chih-Chieh
;
Fan, Chia-Chi
;
Hsu, Hsiao-Hsuan
We demonstrated that the 2.5nm-thick HfAO(x) N-type NCFET based on defect-passivated multidomain switching can achieve a minimum 9 mV/dec subthreshold swing (SS), a negligible hysteresis of 1 mV, an ultralow I-off of 135 fA/mu m, a large I-on/I-off ratio of 8.7x 10(7) and a sub-60 mV/dec SS over 5 decade. For P-type NCFET, the non-hysteretic steep-slope switch is still reached under the synergistic effect of gate stress, defect passivation and doping engineering. The Al doping and defect passivation play the key role for reducing trap-related leakage, enhancing NC, and stabilizing multidomain switching. The highly scaled HfAlOx. CMOS NCFET shows the potential for low power logic applications.
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.