Browsing by Author "Huang, Zhong-Ying"

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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.