Browsing by Author "Wang, HP"

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A new small-signal MOSFET model and parameter extraction method for RF IC's application
(2004-09-01)
Chang, KM
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Wang, HP
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電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, an accurate and simple small signal model of RF MOSFETs accounting for the distributed gate effect, the substrate parasitics and charge conservation is proposed. Meanwhile, a direct and accurate extraction method using linear regression approach for the components of the equivalent circuit of the MOSFET with S-parameters analysis is also proposed. The proposed model and extraction method are verified with the experimental data and an excellent agreement is obtained up to 10 GHz. The extraction results from the measured data for various bias conditions are presented. Also, the extracted parameters, such as transconductance g(m), match well with those obtained from DC measurements. Besides, it is shown that a significant error in circuit performances would be found if the charge conservation is not properly considered. (C) 2004 Elsevier Ltd. All rights reserved.
A simple 2D analytical threshold voltage model for fully depleted short-channel silicon-on-insulator MOSFETs
(2004-12-01)
Chang, KM
;
Wang, HP
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this paper, we propose a simple two-dimensional (2D) analytical threshold voltage model for deep-submicrometre fully depleted SOI MOSFETs using the three-zone Green's function technique to solve the 2D Poisson equation and adopting a new concept of the average electric field to avoid iterations in solving the position of the minimum surface potential. Firstly, we obtain the 2D potential distribution in the Si-film region by using the Green's function technique to solve the 2D Poisson equation. Then, by applying Gauss's law at the Si-SiO2 interface, the initial expression of the threshold voltage is obtained. Eventually, we introduce a modified factor to compensate for the errors resulting from the charge-sharing effect in the derivations of the final threshold voltage model. The proposed model is validated against the results obtained by 2D numerical analysis and experimental data, and excellent agreements are obtained. The proposed model has an explicit expression and can be implemented into the circuit simulator.
Counter-current chromatography using supercritical fluid carbon dioxide as mobile phase
(1996-02-16)
Yu, T
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Li, SE
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Chen, YH
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Wang, HP
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應用化學系
Supercritical fluid carbon dioxide was employed in solar eccentric counter-current chromatography (SECCC) to replace the liquid mobile phase in the traditional arrangement. The fundamental difference from the conventional liquid-liquid system is the requirement for high-pressure operation. The experimental set-up is presented to illustrate the necessary modifications that accommodate operation with a supercritical fluid. Studies on the stationary phase retention due to various experimental conditions are discussed. A mixture of acetophenone and benzophenone was chromatographed using mixtures of water and methanol as the stationary solvent system to demonstrate the feasibility of this technique. At present the efficiency of the separation is not satisfactory owing to the phase separator inserted in the system to remove liquid droplets which contributed to considerable peak broadening.