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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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Author: search.filters.author.Wu, Yu-Sheng

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Now showing 1 - 10 of 23
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    Fabrication and characteristics of a GaN-based microcavity laser with shallow etched mesa
    (2014-06-01)
    Lai, Ying-Yu
    ;
    Chou, Yu-Hsun
    ;
    Wu, Yu-Sheng
    ;
    Lan, Yu-Pin
    ;
    Lu, Tien-Chang
    In this work, we have developed a simple GaN-based microcavity (MC) with an intracavity shallow etched mesa. The textured GaN-based MC incorporated two high-reflectivity dielectric Bragg mirrors and an InGaN/GaN multiple quantum well with a shallow etched mesa as an optical confined structure. Lasing and transverse optical confinement characteristics have been verified by measuring devices with different mesa diameters. A quality factor (Q) of 2600 and a threshold energy of 30 nJ have been observed in a 10-mu m-diameter device. Such a cavity structure could be implanted into electrically pumped GaN vertical-cavity surface-emitting lasers for supporting efficient transverse confinement. (C) 2014 The Japan Society of Applied Physics
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    Impact of Surface Orientation on the Sensitivity of FinFETs to Process Variations-An Assessment Based on the Analytical Solution of the Schrodinger Equation
    (2010-12-01)
    Wu, Yu-Sheng
    ;
    Su, Pin
    ;
    電子工程學系及電子研究所
    ;
    Department of Electronics Engineering and Institute of Electronics
    This paper investigates the impact of surface orientation on V(th) sensitivity to process variations for Si and Ge fin-shaped field-effect transistors (FinFETs) using an analytical solution of the Schrodinger equation. Our theoretical model considers the parabolic potential well due to short-channel effects and, therefore, can be used to assess the quantum-confinement effect in short-channel FinFETs. Our study indicates that, for ultrascaled FinFETs, the importance of channel thickness (t(ch)) variations increases due to the quantum-confinement effect. The Si-(100) and Ge-(111) surfaces show lower V(th) sensitivity to the t(ch) variation as compared with other orientations. On the contrary, the quantum-confinement effect reduces the V(th) sensitivity to the L(eff) variation, and Si-(111) and Ge-(100) surfaces show lower V(th) sensitivity as compared with other orientations. Our study may provide insights for device design and circuit optimization using advanced FinFET technologies.
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    Impact of Quantum Confinement on Short-Channel Effects for Ultrathin-Body Germanium-on-Insulator MOSFETs
    (2011-01-01)
    Wu, Yu-Sheng
    ;
    Hsieh, Hsin-Yuan
    ;
    Hu, Vita Pi-Ho
    ;
    Su, Pin
    ;
    電子工程學系及電子研究所
    This letter investigates the impact of quantum confinement (QC) on the short-channel effect (SCE) of ultrathin-body (UTB) and thin-buried-oxide germanium-on-insulator (GeOI) MOSFETs using an analytical solution of Schrodinger equation verified with TCAD simulation. Our study indicates that, although the QC effect increases the threshold voltage (V(th)) roll-off when the channel thickness (T(ch)) is larger than a critical value (T(ch,crit)), it may decrease the V(th) roll-off of GeOI MOSFETs when the T(ch) is smaller than T(ch,crit). Since Ge and Si channels exhibit different degrees of confinement and T(ch,crit), the impact of QC must be considered when one-to-one comparisons between UTB GeOI and Si-on-insulator MOSFETs regarding the SCE are made.
  • Thumbnail Image
    Item type:Item,
    Fabrication and characteristics of a GaN-based microcavity laser with shallow etched mesa
    (2014-06-01)
    Lai, Ying-Yu
    ;
    Chou, Yu-Hsun
    ;
    Wu, Yu-Sheng
    ;
    Lan, Yu-Pin
    ;
    Lu, Tien-Chang
    In this work, we have developed a simple GaN-based microcavity (MC) with an intracavity shallow etched mesa. The textured GaN-based MC incorporated two high-reflectivity dielectric Bragg mirrors and an InGaN/GaN multiple quantum well with a shallow etched mesa as an optical confined structure. Lasing and transverse optical confinement characteristics have been verified by measuring devices with different mesa diameters. A quality factor (Q) of 2600 and a threshold energy of 30 nJ have been observed in a 10-mu m-diameter device. Such a cavity structure could be implanted into electrically pumped GaN vertical-cavity surface-emitting lasers for supporting efficient transverse confinement. (C) 2014 The Japan Society of Applied Physics
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    Quantum Confinement Effect in Short-Channel Gate-All-Around MOSFETs and Its Impact on the Sensitivity of Threshold Voltage to Process Variations
    (2009)
    Wu, Yu-Sheng
    ;
    Su, Pin
    ;
    電子工程學系及電子研究所
    ;
    Department of Electronics Engineering and Institute of Electronics
    We have proposed an analytical model for quantum confinement effects in short-channel Gate-All-Around (GAA) MOSFETs. This model accurately predicts the eigen-energy shift and eigen-function modulation caused by the short channel effects in lightly doped GAA devices. It shows that the threshold voltage (V(th)) variation due to channel diameter variation is larger than that due to channel length variation because of the significant quantum confinement in ultra-scaled devices. Our model indicates that the channel diameter of GAA MOSFETs can be optimized to reduce the V(th) variation,
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    Investigation of Static Noise Margin of FinFET SRAM Cells in Sub-threshold Region
    (2009)
    Fan, Ming-Long
    ;
    Wu, Yu-Sheng
    ;
    Hu, Vita Pi-Ho
    ;
    Su, Pin
    ;
    Chuang, Ching-Te
    This paper investigates the Static Noise Margin (SNM) of FinFET SRAM cells operating in sub-threshold region using analytical solution of 3D Poisson's equation. An analytical SNM model for sub-threshold FinFET SRAM is demonstrated and validated by TCAD mixed-mode simulations. The stabilities of several novel independently controlled-gate FinFET SRAM cells are examined. Significant nominal RSNM improvements are observed in these novel cells. However, Write-ability is degraded and becomes an important concern for certain configurations in sub-threshold region. Our result indicates that R/W word-line (WL) voltage control technique is more effective than transistor sizing for improving the Write-ability of the FinFET sub-threshold SRAM. While 6T cell is not a viable candidate for sub-threshold SRAM and 8T/10T cells must be used in bulk CMOS, our analysis establishes the feasibility and viability of 6T FinFET cells for sub-threshold SRAM applications.
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    Investigation of Static Noise Margin of Ultra-Thin-Body SOI SRAM Cells in Subthreshold Region using Analytical Solution of Poisson's Equation
    (2009)
    Hu, Vita Pi-Ho
    ;
    Wu, Yu-Sheng
    ;
    Fan, Ming-Long
    ;
    Su, Pin
    ;
    Chuang, Ching-Te
    This paper investigates the Static Noise Margin (SNM) of Ultra-Thin-Body (UTB) SOI SRAM cells operating in subthreshold region using analytical solution of Poisson's equation validated with TCAD simulations. An analytical SNM model for UTB SOI SRAM cells operating in subthreshold region is presented. Our results indicate that back-gate bias (V(bg)) can mitigate the Read SNM (RSNM) variability of UTB SO[ SRAM cells in the subthreshold region, and the improvement of SNM variability is more significant than superthreshold region. Increasing cell beta-ratio shows limited improvement on RSNM and has no benefit on SNM variability for subthreshold operation. The UTB SOI 8T SRAM cell exhibits RSNM 2X larger than the 6T SRAM cell in subthreshold region.
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    Impact of Quantum Confinement on Backgate-Bias Modulated Threshold-Voltage and Subthreshold Characteristics for Ultra-Thin-Body GeOI MOSFETs
    (2012-07-01)
    Yu, Chang-Hung
    ;
    Wu, Yu-Sheng
    ;
    Hu, Vita Pi-Ho
    ;
    Su, Pin
    ;
    電子工程學系及電子研究所
    This paper investigates the impact of quantum confinement (QC) on the backgate-bias (V-bg) modulated subthreshold and threshold-voltage (V-th) characteristics of ultra-thin-body germanium-on-insulator (UTB GeOI) MOSFETs using an analytical solution of the Schrodinger equation verified with TCAD numerical simulation. Our study indicates that the QC effect reduces the sensitivity of the subthreshold swing to V-bg. In addition, the sensitivity of V-th to V-bg can be enhanced by the QC effect particularly for electrostatically well-behaved UTB MOSFETs with triangular potential well. Aside from that, the sensitivity of V-th roll-off to V-bg is reduced by the QC effect. Since Ge and Si channels exhibit different degrees of QC due to different quantization effective mass, the impact of QC has to be considered when one-to-one comparisons between GeOI and SOI MOSFETs regarding the backgate-bias modulated threshold-voltage and subthreshold characteristics are made. Our study may provide insights for multi-V-th device/circuit designs using advanced UTB GeOI technologies.
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    Impact of Quantum Confinement on Subthreshold Swing and Electrostatic Integrity of Ultra-Thin-Body GeOI and InGaAs-OI n-MOSFETs
    (2012-03-01)
    Yu, Chang-Hung
    ;
    Wu, Yu-Sheng
    ;
    Hu, Vita Pi-Ho
    ;
    Su, Pin
    ;
    電子工程學系及電子研究所
    This paper investigates the electrostatic integrity (EI) of ultra-thin-body (UTB) germanium-on-insulator (GeOI) and InGaAs-OI n-MOSFETs considering quantum confinement (QC) using a derived analytical solution of Schrodinger equation verified with TCAD numerical simulation. Although the electron conduction path of the high-mobility channel device can be far from the frontgate interface due to high channel permittivity, our study indicates that the quantum confinement effect can move the carrier centroid toward the frontgate and, therefore, improve the subthreshold swing (SS) of the UTB device. Since InGaAs, Ge, and Si channels exhibit different degrees of quantum confinement due to different quantization effective mass, the impact of quantum confinement has to be considered when one-to-one comparisons among UTB InGaAs-OI, GeOI, and SOI MOSFETs regarding the subthreshold swing and electrostatic integrity are made.
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    A Closed-Form Quantum "Dark Space" Model for Predicting the Electrostatic Integrity of Germanium MOSFETs With High-k Gate Dielectric
    (2012-03-01)
    Wu, Yu-Sheng
    ;
    Su, Pin
    ;
    電子工程學系及電子研究所
    ;
    Department of Electronics Engineering and Institute of Electronics
    This paper provides a closed-form model of the "dark space (DS)" for Ge MOSFETs with high-k gate dielectrics. This model shows accurate dependences on barrier height, surface electric field, and quantization effective mass of the channel and gate dielectric. Our model predicts that the surface DS due to quantum confinement decreases with reverse substrate bias and increasing channel doping. Our model can be also used for devices with a steep retrograde doping profile. This physically accurate model will be crucial to the prediction of the subthreshold swing and electrostatic integrity of advanced Ge devices.