Browsing by Author "Sheu, Yi-Ming"

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A millisecond-anneal-assisted selective fully silicided (FUSI) gate process
(2008-09-01)
Lin, Da-Wen
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Wang, Maureen
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Cheng, Ming-Lung
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Sheu, Yi-Ming
;
Tarng, Bennet
We demonstrate, for the first time, an integration-friendly selective PMOSFET fully silicided (FUSI) gate process. In this process, a millisecond-anneal (NISA) technique is utilized for the nickel silicide phase transformation. A highly tensile FUSI gate electrode is created and hence exerts compressive stress in the underlying channel. The highly flexible integration scheme successfully, and exclusively, implements uniform P+ FUSI gates for PMOSFETs while preserving a FUSI-free N+ poly-Si gate for PMOSFETs with the feature size down to 30 run. A 20% improvement in FUSI-gated PMOSFET I-on-I-off is measured, which can be attributed to the enhanced hole mobility and the elimination of P+ poly-gate depletion.
Effect of uniaxial strain on anisotropic diffusion in silicon
(2006-10-16)
Chen, Ming-Jer
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Sheu, Yi-Ming
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
A physical model is directly extended from the thermodynamic framework to deal with anisotropic diffusion in uniaxially stressed silicon. With the anisotropy of the uniaxial strain induced activation energy as input, two fundamental material parameters, the activation volume and the migration strain anisotropy, can be quantitatively determined. When applied to boron, a process- device coupled simulation is performed on a p-type metal-oxide-semiconductor field-effect transistor undergoing uniaxial stress in a manufacturing process. The resulting material parameters have been found to be in satisfactory agreement with values presented in the literature. (c) 2006 American Institute of Physics.
Modeling the well-edge proximity effect in highly scaled MOSFETs
(2006-11-01)
Sheu, Yi-Ming
;
Su, Ke-Wei
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Tian, Shiyang
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Yang, Sheng-Jier
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Wang, Chih-Chiang
The well-edge proximity effect caused by ion scattering during implantation in highly scaled CMOS technology is explored from a physics and process perspective. Technology computer-aided design (TCAD) simulations together with silicon wafer experiments have been conducted to investigate the impact of this effect. The ion scattering model and TCAD simulations provided a physical understanding of how the internal changes of the MOSFETs are formed. A new compact model for SPICE is proposed using physics-based understanding and has been calibrated using experimental silicon test sets.
Reproducing subthreshold characteristics of metal-oxide-semiconductor field effect transistors under shallow trench isolation mechanical stress using a stress-dependent diffusion model
(2006-08-01)
Sheu, Yi-Ming
;
Yang, Sheng-Jier
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Wang, Chih-Chiang
;
Chang, Chih-Sheng
;
Chen, Ming-Jer
N-channel metal-oxide-semiconductor field effect transistors (MOSFETs) with a lightly doped well exhibit subthreshold current versus voltage (I-V) characteristics that are sensitive to shallow trench isolation (STI) mechanical stress. Such striking dependencies offer the opportunity to validate a proposed two-dimensional (2D) process model that relates the impurity diffusion to the mechanical stress throughout the substrate. With the assistance of sophisticated process/device simulations, the model appears to satisfactorily reproduce subthreshold I-V characteristics for different active area lengths and different substrate biases. The stress-dependent point defect equilibrium concentration and diffusion model are also implemented to evaluate the stress effect on transient enhanced diffusion.