Browsing by Author "Shen, Cheng-Han"

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Device Simulation-Based Multiobjective Evolutionary Algorithm for Process Optimization of Semiconductor Solar Cells
(2013-07-03)
Li, Yiming
;
Chen, Yu-Yu
;
Chen, Chieh-Yang
;
Shen, Cheng-Han
;
Cheng, Hui-Wen
This article implements for the first time a numerical semiconductor device simulation-based multiobjective evolutionary algorithm (MOEA) for the characteristic optimization of amorphous silicon thin-film solar cells, based upon a unified optimization framework (UOF). To calculate the device's characteristic, a set of coupled solar cell transport equations consisting of the Poisson equation, the electron-hole current continuity equations, and the photo-generation model is solved numerically. Electrical characteristics, the short-circuited current, the open-circuited voltage, and the conversion efficiency are calculated to analyze the properties of the explored solar cells. The aforementioned device simulation results are used to evaluate the fitness score and access the evolutionary quality of designing parameters via the implemented non-dominating sorting genetic algorithm (NSGA-II) in the UOF. Notably, designing parameters including the material and structural parameters, and the doping concentrations are simultaneously optimized for the explored solar cells. The simulation-based MOEA methodology is useful in optimal structure design and manufacturing of semiconductor solar cells.
Modeling Bias Stress Effect on Threshold Voltage for Amorphous Silicon Thin-Film Transistors and Circuits
(2011)
Shen, Cheng-Han
;
Lo, I-Hsiu
;
Li, Yiming
;
電機學院
;
電子工程學系及電子研究所
In this paper, we study amorphous silicon thin-film-transistor (TFT) degradation under bias stress effect. To model threshold voltage shift with bias stress effect, fabricated samples are measured for I-V data with bias stress in variations of temperature. Rensselaer Polytechnic Institute (RPI) model is thus adopted to extract model parameters, such as the fiat band voltage (V-FB), the characteristic voltage for deep states (V-O), the conduction band mobility (MUBAND), the channel length modulation parameter (LAMBDA), the power law mobility parameter (GAMMA) and the saturation modulation parameter (ALPHASAT) from the measurement. The model card with those extracted parameters is validated via a TFT circuit simulation. The results of the circuit simulation indicate the relationship of effects depending on the stress and operational temperature.