In this study,numerical simulations of the pinching-off phenomena displayed by the dispersed phase in a continuous phase have been conducted using COMSOL Multiphysics(level-set method).Four flow patterns,namely“drop ...In this study,numerical simulations of the pinching-off phenomena displayed by the dispersed phase in a continuous phase have been conducted using COMSOL Multiphysics(level-set method).Four flow patterns,namely“drop flow”,“jet flow”,“squeeze flow”,and“co-flow”,have been obtained for different flow velocity ratios,channel diameter ratios,density ratios,viscosity ratios,and surface tension.The flow pattern map of two-phase flow in coaxial microchannels has been obtained accordingly,and the associated droplet generation process has been critically discussed considering the related frequency,diameter,and pinch-off length.In particular,it is shown that the larger the flow velocity ratio,the smaller the diameter of generated droplets and the shorter the pinch-off length.The pinch-off length of a droplet is influenced by the channel diameter ratio and density ratio.The changes in viscosity ratio have a negligible influence on the droplet generation pinching frequency.With an increase in surface tension,the frequency of generation and pinch-off length of droplets decrease,but for small surface tension the generation diameter of droplet increases.展开更多
A novel analytical model of pinch-off voltage for CMOS image pixels with a pinned photodiode structure is proposed. The derived model takes account of the gradient doping distributions in the N buried layer due to the...A novel analytical model of pinch-off voltage for CMOS image pixels with a pinned photodiode structure is proposed. The derived model takes account of the gradient doping distributions in the N buried layer due to the impurity compensation formed by manufacturing processes; the impurity distribution characteristics of two boundary PN junctions located in the region for particular spectrum response of a pinned photodiode are quantitative analyzed. By solving Poisson＇s equation in vertical barrier regions, the relationships between the pinch-off voltage and the corresponding process parameters such as peak doping concentration, N type width and doping concentration gradient of the N buried layer are established. Test results have shown that the derived model features the variations of the pinch-off voltage versus the process implant conditions more accurately than the traditional model. The research conclusions in this paper provide theoretical evidence for evaluating the pinch-off voltage design.展开更多
An approach to obtain the pinch-off voltage of 4-T pixel in CMOS image sensor is presented.This new approach is based on the assumption that the photon shot noise in image signal is impacted by a potential well struct...An approach to obtain the pinch-off voltage of 4-T pixel in CMOS image sensor is presented.This new approach is based on the assumption that the photon shot noise in image signal is impacted by a potential well structure change of pixel.Experimental results show the measured pinch-off voltage is consistent with theoretical prediction.This technique provides an experimental method to assist the optimization of pixel design in both the photodiode structure and fabrication process for the 4-T CMOS image sensor.展开更多
The mixed non-saturating I-V characteristics of static induction transistor (SIT) are investigated.The optimum matching relations among the structural,material,and technological parameters are also presented.The techn...The mixed non-saturating I-V characteristics of static induction transistor (SIT) are investigated.The optimum matching relations among the structural,material,and technological parameters are also presented.The technological experiments demonstrate that the channel parameters play a critical role in determining whether it is a mixed,triode-like or pentode-like I-V characteristics.The general control principles,methods,and criterions of fabrication parameters as well as the effect of control factor are analytically discussed.The results are useful for design and fabrication of SIT,especially for SIT with mixed I-V characteristics.展开更多
The degradation characteristics of both wide and narrow devices under V _g= V _d/2 stress mode is investigated.The width-enhanced device degradation can be seen with devices narrowing.The main degradation mechanism is...The degradation characteristics of both wide and narrow devices under V _g= V _d/2 stress mode is investigated.The width-enhanced device degradation can be seen with devices narrowing.The main degradation mechanism is interface state generation for pMOSFETs with different channel width.The cause of the width-enhanced device degradation is attributed to the combination of width-enhanced threshold voltage and series resistance.展开更多
基金funded by University Natural Science Research Project of Anhui Province,Grant Numbers (KJ2020A0826,2022AH051885,2022AH051891,2022AH030160,62303231)Intelligent Detection Research Team Funds for the Anhui Institute of Information Technology,Grant Number (AXG2023_kjc_5004).
文摘In this study,numerical simulations of the pinching-off phenomena displayed by the dispersed phase in a continuous phase have been conducted using COMSOL Multiphysics(level-set method).Four flow patterns,namely“drop flow”,“jet flow”,“squeeze flow”,and“co-flow”,have been obtained for different flow velocity ratios,channel diameter ratios,density ratios,viscosity ratios,and surface tension.The flow pattern map of two-phase flow in coaxial microchannels has been obtained accordingly,and the associated droplet generation process has been critically discussed considering the related frequency,diameter,and pinch-off length.In particular,it is shown that the larger the flow velocity ratio,the smaller the diameter of generated droplets and the shorter the pinch-off length.The pinch-off length of a droplet is influenced by the channel diameter ratio and density ratio.The changes in viscosity ratio have a negligible influence on the droplet generation pinching frequency.With an increase in surface tension,the frequency of generation and pinch-off length of droplets decrease,but for small surface tension the generation diameter of droplet increases.
文摘A novel analytical model of pinch-off voltage for CMOS image pixels with a pinned photodiode structure is proposed. The derived model takes account of the gradient doping distributions in the N buried layer due to the impurity compensation formed by manufacturing processes; the impurity distribution characteristics of two boundary PN junctions located in the region for particular spectrum response of a pinned photodiode are quantitative analyzed. By solving Poisson＇s equation in vertical barrier regions, the relationships between the pinch-off voltage and the corresponding process parameters such as peak doping concentration, N type width and doping concentration gradient of the N buried layer are established. Test results have shown that the derived model features the variations of the pinch-off voltage versus the process implant conditions more accurately than the traditional model. The research conclusions in this paper provide theoretical evidence for evaluating the pinch-off voltage design.
基金Project supported by the National Natural Science Foundation of China(Nos.60806010,60976030)the Tianjin Innovation Special Funds for science and Technology,China(No.05FZZDGX00200).
文摘An approach to obtain the pinch-off voltage of 4-T pixel in CMOS image sensor is presented.This new approach is based on the assumption that the photon shot noise in image signal is impacted by a potential well structure change of pixel.Experimental results show the measured pinch-off voltage is consistent with theoretical prediction.This technique provides an experimental method to assist the optimization of pixel design in both the photodiode structure and fabrication process for the 4-T CMOS image sensor.
文摘The mixed non-saturating I-V characteristics of static induction transistor (SIT) are investigated.The optimum matching relations among the structural,material,and technological parameters are also presented.The technological experiments demonstrate that the channel parameters play a critical role in determining whether it is a mixed,triode-like or pentode-like I-V characteristics.The general control principles,methods,and criterions of fabrication parameters as well as the effect of control factor are analytically discussed.The results are useful for design and fabrication of SIT,especially for SIT with mixed I-V characteristics.
文摘The degradation characteristics of both wide and narrow devices under V _g= V _d/2 stress mode is investigated.The width-enhanced device degradation can be seen with devices narrowing.The main degradation mechanism is interface state generation for pMOSFETs with different channel width.The cause of the width-enhanced device degradation is attributed to the combination of width-enhanced threshold voltage and series resistance.
