Browsing by Author "Ku, Chih-You"

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Flicker Noise in Nanoscale pMOSFETs with Mobility Enhancement Engineering and Dynamic Body Biases
(2009)
Yeh, Kuo-Liang
;
Ku, Chih-You
;
Hong, Wei-Lun
;
Guo, Jyh-Chyurn
;
電子工程學系及電子研究所
The uni-axial compressive strain from e-SiGe S/D combined with dynamic body biases effect on flicker noise of pMOSFETs is presented in this paper. This compressive strain contributes higher mobility but the worse flicker noise in terms of higher S(ID)/I(D)(2) becomes a potential killer to RF/analog circuits. Forward body biases (FBB) can reduce the flicker noise but the degraded body bias effect in strained pMOSFETs makes it not as efficient as the standard ones without strain. Hooge's mobility fluctuation model is adopted to explain the uni-axial strain and dynamic body biases effect on flicker noise. The increase of Hooge parameter alpha(H) is identified the key factor responsible the degraded flicker noise in strained pMOSFETs.
Low Frequency Noise in Nanoscale pMOSFETs with Strain Induced Mobility Enhancement and Dynamic Body Biases
(2009)
Yeh, Kuo-Liang
;
Ku, Chih-You
;
Hong, Wei-Lun
;
Guo, Jyh-Chyurn
;
電子工程學系及電子研究所
Local strain effect on low frequency noise (LFN) of pMOSFETs with gate length down to 60 nm was investigated in this paper. Novel and interesting results were identified from the pMOSFETs adopting embedded SiGe (e-SiGe) in source/drain for uni-axial compressive stress. This local compressive strain can realize significant mobility enhancement and desired current boost in nanoscale pMOSFETs. However, the dramatic increase of LFN emerges as a penalty traded off with mobility enhancement. The escalated LFN may become a critical killer to analog and RF circuits. Forward body biases (FBB) can improve the effective mobility (mu(eff)) and reduce LFN attributed to reduced normal field (E(eff)). However, the benefit from FBB becomes insignificant in strained pMOSFETs with sub-100 nm gate length.
The Impact of Layout Dependent Stress and Gate Resistance on High Frequency Performance and Noise in Multifinger and Donut MOSFETs
(2013)
Ku, Chih-You
;
Yeh, Kuo-Ling
;
Guo, Jyh-Chyurn
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The impact of STI stress on mobility and resulted transconductance (g(m)) degradation appear as a penalty of multi-finger devices for RF and analog design. Donut device layout is proposed to eliminate the STI transverse stress and achieve higher g(m). Both NMOS and PMOS can benefit from the donut layout, with higher cut-off frequency (f(T)). However, the layout dependence of g(m) and gate resistance (R-g) becomes a critical trade-off in determining high frequency performance other than f(T), such as maximum oscillation frequency (f(max)) and RF noise. In this paper, a comparison between multi-finger and donut MOSFETs in terms of f(T), f(max), and NFmin can provide a useful guideline of device layout for RF design using nanoscale CMOS technology.
The Impact of MOSFET Layout Dependent Stress on High Frequency Characteristics and Flicker Noise
(2010)
Yeh, Kuo-Liang
;
Ku, Chih-You
;
Guo, Jyh-Chyurn
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Layout dependent stress in 90 nm MOSFET and its impact on high frequency performance and flicker noise has been investigated. Donut MOSFETs were created to eliminate the transverse stress from shallow trench isolation (STI). Both NMOS and PMOS can benefit from the donut layout in terms of higher effective mobility mu(eff) and cutoff frequency f(T), as well as lower flicker noise. The measured flicker noise follows number fluctuation model for NMOS and mobility fluctuation model for PMOS, respectively. The reduction of flicker noise suggests the reduction of STI generated traps and the suppression of mobility fluctuation due to eliminated transverse stress using donut structure.
The Impact of Uni-axial Strain on Low Frequency Noise in Nanoscale p-Channel Metal-Oxide-Semiconductor Field Effect Transistors under Dynamic Body Biases
(2010-08-01)
Yeh, Kuo-Liang
;
Ku, Chih-You
;
Guo, Jyh-Chyurn
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The impact of local strain on low frequency noise (LFN) in p-channel metal-oxide-semiconductor field effect transistor (pMOSFET) is investigated under dynamic body biases For 60 nm pMOSFET, the uni-axial compressive strain from embedded SiGe (e-SiGe) in source/drain can contribute 75% effective mobility (mu(eff)) enhancement and the proportional improvement in current (I(DS)) as well as transconductance (G(m)) However, the strained pMOSFET suffer more than 80% higher LFN (S(ID)/I(D)(2)) compared with the control pMOSFET free from strain engineering The measured LFN can be consistently explained by mobility fluctuation model and the increase of Hooge parameter (alpha(H)) appears as a key factor responsible for the higher LFN in strained pMOSFET Forward body biases (FBB) is proposed as an effective method adapted to nanoscale devices for improving mu(eff) and suppressing LFN, without resort to strain engineering (C) 2010 The Japan Society of Applied Physics