Browsing by Author "Yiu, Chun-Yen"

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3D Device Simulation of Work Function and Interface Trap Fluctuations on High-kappa/Metal Gate Devices
(2010)
Cheng, Hui-Wen
;
Li, Fu-Hai
;
Han, Ming-Hung
;
Yiu, Chun-Yen
;
Yu, Chia-Hui
This work, for the first time, examines the work function fluctuation (WKF) and interface trap fluctuation (ITF) using experimentally calibrated 3D device simulation on high-kappa / metal gate technology. The random WKs result in 36.7 mV threshold voltage fluctuation (sigma V(th)) for 16 nm N-MOSFETs with TiN gate, which is rather different from the result of averaged WKF (AWKF) method [1] due to localized random WK effect. The ITF affects the subthreshold region (the normalized sigma I(D) > 48%) and is suppressed for devices under strong inversion. Estimation of statistical covariance confirms the dependence of IT on the metal gate's WK; thus, the impacts of WKF and ITF on device and circuit variability should be considered together properly. Such variability induced static noise margin fluctuation of SRAM exceeds the influence of random dopants and cannot be ignored.
A Unified 3D Device Simulation of Random Dopant, Interface Trap and Work Function Fluctuations on High-kappa/Metal Gate Device
(2011)
Li, Yiming
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Cheng, Hui-Wen
;
Chiu, Yung-Yueh
;
Yiu, Chun-Yen
;
Su, Hsin-Wen
In this work, we for the first time estimate total fluctuation resulting from random dopants (RDs), interface trap (ITs) and work functions (WKs) using experimentally calibrated 3D device simulation on 16-nm-gate high-kappa/metal gate devices. The total 3D simulated threshold voltage fluctuation (sigma V-th), induced by the aforementioned random sources simultaneously, is 55.5 mV for NMOS; however, a statistical total sum of these fluctuations is 12.3% overestimation because independence assumption on random variables is invalid owing to strong interactions among RDs, ITs and WKs. Device's DC/AC and CMOS SRAM circuit fluctuations have similar observation. FinFET-based structure innovation possessing large fluctuation suppression (sigma V-th = 30.2 mV; 45.6% reduction), compared with process efforts on planar one, is further discussed.
Dual-Material Gate Approach to Suppression of Random-Dopant-Induced Characteristic Fluctuation in 16 nm Metal-Oxide-Semiconductor Field-Effect-Transistor Devices
(2011-04-01)
Li, Yiming
;
Lee, Kuo-Fu
;
Yiu, Chun-Yen
;
Chiu, Yung-Yueh
;
Chang, Ru-Wei
In this work, we explore for the first time dual-material gate (DMG) and inverse DMG devices for suppressing the random-dopant (RD)-induced characteristic fluctuation in 16 nm metal-oxide-semiconductor field-effect-transistor (MOSFET) devices. The physical mechanism of suppressing the characteristic fluctuation of DMG devices is observed and discussed. The achieved improvement in suppressing the RD-induced threshold voltage, on-state current, and off-state current fluctuations are 28, 12.3, and 59%, respectively. To further suppress the fluctuations, an approach that combines the DMG method and channel-doping-profile engineering is also advanced and explored. The results of our study show that among the suppression techniques, the use of the DMG device with an inverse lateral asymmetric channel-doping-profile has good immunity to fluctuation. (C) 2011 The Japan Society of Applied Physics
Nanosized metal grains induced electrical characteristic fluctuation in 16-nm-gate high-kappa/metal gate bulk FinFET devices
(2011-07-01)
Li, Yiming
;
Cheng, Hui-Wen
;
Yiu, Chun-Yen
;
Su, Hsin-Wen
;
傳播研究所
In this work, the work function fluctuation (WKF) induced variability in 16-nm-gate bulk N-FinFET is for the first time explored by an experimentally calibrated 3D device simulation. Random nanosized grains of TiN gate are statistically positioned in the gate region to examine the associated carriers' transport, concurrently capturing "grain number variation" and "grain position fluctuation." The newly developed localized WKF simulation method enables us to estimate the threshold voltage fluctuation of devices with respect to the aspect ratio (AR = fin height/fin width) which accounts for the random grain's size, number and position effects simultaneously. (C) 2011 Elsevier B.V. All rights reserved.