Browsing by Author "Wang, Y. -H."

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A Comprehensive Study of Polymorphic Phase Distribution of Ferroelectric-Dielectrics and Interfacial Layer Effects on Negative Capacitance FETs for Sub-5 nm Node
(2018-01-01)
Tang, Y. -T
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Su, C. -J.
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Wang, Y. -S.
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Kao, K. -H.
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Wu, T. -L.
The impact of a realistic representation of gate-oxide granularity on negative-capacitance (NC) FETs at sub-5nm node is studied by a newly developed thermodynamic energy model based on the first principle calculation (FPC). For the first time, the calculation fully couples the Landau-Khalatnikov (L-K) equation with grain-size effect equation in NC-FETs. It explains the experimental results in phase transition and reveals excellent immunity against depolarization in ferroelectric (FE) layer owing to dopant concentration and stress in thin films. A sub-5nm node (L-G=10nm) NC-FET with thin FE layer (T-FE similar to 2nm) is integrated to achieve low subthreshold slope (SS) of 52mV/dec via a 1.9GPa-tensor stressed interfacial layer (IL) and 12% Zr-doped HfO2.
First Demonstration of CMOS Inverter and 6T-SRAM Based on GAA CFETs Structure for 3D-IC Applications
(2019-01-01)
Chang, S. -W.
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Sung, P. -J.
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Chu, T-Y.
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Lu, D. D.
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Wang, C. -J.
For the first time, CMOS inverters and 6T-SRAM cells based on vertically stacked gate-all-around complementary FETs (CFETs) are experimentally demonstrated. Manufacturing difficulties of vertically stacked source and drain electrodes of the CFETs have been overcome by using junctionless transistors, thereby reducing the number of lithographic steps required. Furthermore, with post metallization treatments, both the voltage transfer characteristics (VTCs) of CMOS inverters and butterfly curves of SRAM show significant improvements due to the symmetry of nMOS and pMOS threshold voltages. Simulation shows that 3-dimensional CFET inverters have lower input parasitic capacitance than standard 2-dimensional CMOS, leading to reduced gate delay and lower power consumption.
Ge Nanowire FETs with HfZrOx Ferroelectric Gate Stack Exhibiting SS of Sub-60 mV/dec and Biasing Effects on Ferroelectric Reliability
(2017-01-01)
Su, C. -J.
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Hong, T. -C.
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Tsou, Y. -C.
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Hou, F. -J.
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Sung, P. -J.
Ge nanowire (NW) FETs exhibiting subthreshold swing (SS) of 54 mV/dec at room temperature are demonstrated with ferroelectric HfZrOx (FE-HZO) gate stack for the first time. I-ON/I-OFF ratios higher than 10(7) and 10(6) for p- and n-NWFETs, respectively, have been achieved by adopting the gate-all-around (GAA) configuration. Electrical biasing effects on the HZO ferroelectric reliability have been systematically investigated in this work. It is found that the polarization behavior will degrade with electrical stress time and can be recovered. The Ge HZO FinFET CMOS inverter shows experimentally voltage gain of 24.8 V/V.
High Performance Complementary Ge Peaking FinFETs by Room Temperature Neutral Beam Oxidation for Sub-7 nm Technology Node Applications
(2016-01-01)
Lee, Y. -J.
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Hong, T. -C.
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Hsueh, F. -K.
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Sung, P. J.
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Chen, C. -Y.
Ge peaking n- and p-FinFETs have been demonstrated by adopting neutral beam etching (NBE) and anisotropic neutral beam oxidation (NBO) processes. The irradiation-free NB processes not only suppress surface roughness but also guarantee low defect generation on the etched Ge surface. The fabricated Ge peaking FinFETs possess several unique features: (1) A peaking fin configuration with a 6-nm top-gate formed by an anisotropic NBO process at room temperature. (2) Nearly defect-free three dimensional channel surfaces by NB processes. (3) ION and Gm improvement by NB processes as compared to that by conventional inductively coupled plasma etching (ICP). (4) Recorded high I-ON/I-OFF ratio and low subthreshold swing (S.S. similar to 70 mV/dec.) of Ge n-FinFETs. (5) Excellent immunity for short channel effect of Ge FinFETs.
Voltage Transfer Characteristic Matching by Different Nanosheet Layer Numbers of Vertically Stacked Junctionless CMOS Inverter for SoP/3D-ICs applications
(2018-01-01)
Sung, P. -J.
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Chang, C. -Y.
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Chen, L. -Y.
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Kao, K. -H.
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Su, C. -J.
For the first time, CMOS inverters with different numbers of vertically stacked junctionless (JL) nanosheets (NSs) are demonstrated. All fabrication steps were below 600 degrees C, and 8-nm thick poly-Si NSs with smooth surface roughness were formed by a dry etching process. Compared to single channel devices, stacked n/p-channel FETs exhibit higher on-current with low leakage current. Furthermore, a common-gate process was performed for the fabrication of CMOS inverters. By adjusting the NS layer numbers for n/pFETs, respectively, the voltage transfer characteristics (VTCs) of the CMOS inverter can be matched much better to reduce the noise margin due to on-current matching without area penalty. This work experimentally demonstrates a new configuration of CMOS inverters on stacked NSs, which is promising for System-on-Panel (SoP) and 3D-ICs applications.