Browsing by Author "Fan, Yu-Chi"

Now showing 1 - 5 of 5

Characteristic Simulation of Hybrid Multilayer Junctionless Field Effect Transistors with Negative Capacitance Effect
(2020-01-01)
Ma, Jun
;
Liu, Chien
;
Liu, Wei-Dong
;
Hung, Yu-Wen
;
Fan, Yu-Chi
In this study, we reported a hybrid multi-PNPN channel junctionless field effect transistor (JLFET) with negative capacitance (NC) effect by simulation. By incorporating a ferroelectric HfAlO capacitor with NC effect, an extremely low subthreshold swing of 34 mVdecade, a very high onoff current ratio and a very low driven voltage were achieved in the NC-enhanced hybrid multi-PNPN channel JLFET. This novel device not only improves the on-state current reduction while channel scaling down, but also shows great potential for the next-generation low-power three-dimensional stacked integrated circuit applications.
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
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 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.
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.