The tunnel field-effect transistor(TFET) is a potential candidate for the post-CMOS era.As one of the most important electrical parameters of a device,double gate TFET(DG-TFET) gate threshold voltage was studied.First...The tunnel field-effect transistor(TFET) is a potential candidate for the post-CMOS era.As one of the most important electrical parameters of a device,double gate TFET(DG-TFET) gate threshold voltage was studied.First,a numerical simulation study of transfer characteristic and gate threshold voltage in DG-TFET was reported.Then,a simple analytical model for DG-TFET gate threshold voltage VTG was built by solving quasi-two-dimensional Poisson equation in Si film.The model as a function of the drain voltage,the Si layer thickness,the gate length and the gate dielectric was discussed.It is shown that the proposed model is consistent with the simulation results.This model should be useful for further investigation of performance of circuits containing TFETs.展开更多
The tunneling field-effect transistor（TFET） is a potential candidate for the post-CMOS era.In this paper,a threshold voltage model is developed for this new kind of device.First,two-dimensional（2D） models are used...The tunneling field-effect transistor（TFET） is a potential candidate for the post-CMOS era.In this paper,a threshold voltage model is developed for this new kind of device.First,two-dimensional（2D） models are used to describe the distributions of potential and electric field in the channel and two depletion regions.Then based on the physical definition of threshold voltage for the nanoscale TFET,the threshold voltage model is developed.The accuracy of the proposed model is verified by comparing the calculated results with the 2D device simulation data.It has been demonstrated that the effects of varying the device parameters can easily be investigated using the model presented in this paper.This threshold voltage model provides a valuable reference to TFET device design,simulation,and fabrication.展开更多
A physically based analytical model was developed to predict the performance of the plateau observed in the gate C-V characteristics of strained-Si/SiGe pMOSFET.Experimental results were used to validate this model.Th...A physically based analytical model was developed to predict the performance of the plateau observed in the gate C-V characteristics of strained-Si/SiGe pMOSFET.Experimental results were used to validate this model.The extracted parameters from our model were tOX=20 nm,ND=1×1016cm 3,tSSi=13.2 nm,consistent with the experimental values.The results show that the simulation results agree with experimental data well.It is found that the plateau can be strongly affected by doping concentration,strained-Si layer thickness and mass fraction of Ge in the SiGe layer.The model has been implemented in the software for strained silicon MOSFET parameter extraction,and has great value in the design of the strained-Si/SiGe devices.展开更多
The effect of substrate doping on the flatband and threshold voltages of a strained-Si/SiGe p metal-oxide semiconductor field-effect transistor（pMOSFET） has been studied.By physically deriving the models of the flat...The effect of substrate doping on the flatband and threshold voltages of a strained-Si/SiGe p metal-oxide semiconductor field-effect transistor（pMOSFET） has been studied.By physically deriving the models of the flatband and threshold voltages,which have been validated by numerical simulation and experimental data,the shift in the plateau from the inversion region to the accumulation region as the substrate doping increases has been explained.The proposed model can provide a valuable reference to the designers of strained-Si devices and has been implemented in software for extracting the parameters of a strained-Si MOSFET.展开更多
An analytical expression for the co/lector resistance of a novel vertical SiGe heterojunction bipolar transistor （HBT） on thin film silicon-on-insulator （SOI） is obtained with the substrate bias effects being cons...An analytical expression for the co/lector resistance of a novel vertical SiGe heterojunction bipolar transistor （HBT） on thin film silicon-on-insulator （SOI） is obtained with the substrate bias effects being considered. The resistance is found to decrease slowly and then quickly and to have kinks with the increase of the substrate-collector bias, which is quite different from that of a conventional bulk HBT. The model is consistent with the simulation result and the reported data and is useful to the frequency characteristic design of 0.13 μtm millimeter-wave SiGe SOI BiCMOS devices.展开更多
The effect of substrate doping on the threshold voltages of buried channel pMOSFET based on strained-SiGe technology was studied.By physically deriving the models of the threshold voltages,it is found that the layer w...The effect of substrate doping on the threshold voltages of buried channel pMOSFET based on strained-SiGe technology was studied.By physically deriving the models of the threshold voltages,it is found that the layer which inversely occurs first is substrate doping dependent,giving explanation for the variation of plateau observed in the C-V characteristics of this device,as the doping concentration increases.The threshold voltages obtained from the proposed model are-1.2805 V for buried channel and-2.9358 V for surface channel at a lightly doping case,and-3.41 V for surface channel at a heavily doping case,which agrees well with the experimental results.Also,the variations of the threshold voltages with several device parameters are discussed,which provides valuable reference to the designers of strained-SiGe devices.展开更多
In this paper, we propose an analytical avalanche multiplication model for the next generation of SiGe silicon- on-insulator （SOI） heterojunction bipolar transistors （HBTs） and consider their vertical and lateral ...In this paper, we propose an analytical avalanche multiplication model for the next generation of SiGe silicon- on-insulator （SOI） heterojunction bipolar transistors （HBTs） and consider their vertical and lateral impact ionizations for the first time. Supported by experimental data, the analytical model predicts that the avalanche multiplication governed by impact ionization shows kinks and the impact ionization effect is small compared with that of the bulk HBT, resulting in a larger base-collector breakdown voltage. The model presented in the paper is significant and has useful applications in the design and simulation of the next generation of SiCe SOI BiCMOS technology.展开更多
With RF sputtering process, Si/Si02/Ta/Ru/Ta/CoFeB/MgO/CoFeB/Ta/Ru structure has been grown on Si （100） substrate. Attempting different targets and adjusting the oxygen dose, the crystallization quality of the MgO l...With RF sputtering process, Si/Si02/Ta/Ru/Ta/CoFeB/MgO/CoFeB/Ta/Ru structure has been grown on Si （100） substrate. Attempting different targets and adjusting the oxygen dose, the crystallization quality of the MgO layer is studied. The X-ray diffraction measurements demonstrate that crystal structure and crystallization quality of MgO layers are related to the type of target and concentration of oxygen in sputtering process. With the method sputtering Mg in an ambient flow of oxygen, not only the crystallization quality of a normal MgO layer with lattice constant of 0.421 nm is improved, but also a new MgO crystal with lattice constant of 0.812 nm is formed and the perpendicular magnetic anisotropy of CoFeB is enhanced. Also it is found that crystallization quality for both the normal MgO and new MgO is more improved with MgO target and same oxygen dose, which means that this new method is helpful to form a new structure of MgO annealed at 400 ℃ in vacuum. with lattice constant of 0.812 nm. All of the samples were展开更多
基金Project(P140c090303110c0904)supported by NLAIC Research Fund,ChinaProject(JY0300122503)supported by the Research Fund for the Doctoral Program of Higher Education of China+1 种基金Projects(K5051225014,K5051225004)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2010JQ8008)supported by the Natural Science Basic Research Plan in Shaanxi Province of China
文摘The tunnel field-effect transistor(TFET) is a potential candidate for the post-CMOS era.As one of the most important electrical parameters of a device,double gate TFET(DG-TFET) gate threshold voltage was studied.First,a numerical simulation study of transfer characteristic and gate threshold voltage in DG-TFET was reported.Then,a simple analytical model for DG-TFET gate threshold voltage VTG was built by solving quasi-two-dimensional Poisson equation in Si film.The model as a function of the drain voltage,the Si layer thickness,the gate length and the gate dielectric was discussed.It is shown that the proposed model is consistent with the simulation results.This model should be useful for further investigation of performance of circuits containing TFETs.
基金Project supported by the National Ministries and Commissions,China (Grant Nos. 51308040203 and 6139801)the Fundamental Research Funds for the Central Universities,China (Grant Nos. 72105499 and 72104089)the Natural Science Basic Research Plan in Shaanxi Province,China (Grant No. 2010JQ8008)
文摘The tunneling field-effect transistor（TFET） is a potential candidate for the post-CMOS era.In this paper,a threshold voltage model is developed for this new kind of device.First,two-dimensional（2D） models are used to describe the distributions of potential and electric field in the channel and two depletion regions.Then based on the physical definition of threshold voltage for the nanoscale TFET,the threshold voltage model is developed.The accuracy of the proposed model is verified by comparing the calculated results with the 2D device simulation data.It has been demonstrated that the effects of varying the device parameters can easily be investigated using the model presented in this paper.This threshold voltage model provides a valuable reference to TFET device design,simulation,and fabrication.
基金Projects(51308040203,6139801)supported by National Ministries and Commissions,ChinaProjects(72105499,72104089)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(2010JQ8008)supported by the Natural Science Basic Research Plan in Shaanxi Province of China
文摘A physically based analytical model was developed to predict the performance of the plateau observed in the gate C-V characteristics of strained-Si/SiGe pMOSFET.Experimental results were used to validate this model.The extracted parameters from our model were tOX=20 nm,ND=1×1016cm 3,tSSi=13.2 nm,consistent with the experimental values.The results show that the simulation results agree with experimental data well.It is found that the plateau can be strongly affected by doping concentration,strained-Si layer thickness and mass fraction of Ge in the SiGe layer.The model has been implemented in the software for strained silicon MOSFET parameter extraction,and has great value in the design of the strained-Si/SiGe devices.
基金Project supported by the Funds from the National Ministries and Commissions (Grant Nos. 51308040203 and 6139801)the Fundamental Research Funds for the Central Universities (Grant Nos. 72105499 and 72104089)the Natural Science Basic Research Plan in Shaanxi Province of China (Grant No. 2010JQ8008)
文摘The effect of substrate doping on the flatband and threshold voltages of a strained-Si/SiGe p metal-oxide semiconductor field-effect transistor（pMOSFET） has been studied.By physically deriving the models of the flatband and threshold voltages,which have been validated by numerical simulation and experimental data,the shift in the plateau from the inversion region to the accumulation region as the substrate doping increases has been explained.The proposed model can provide a valuable reference to the designers of strained-Si devices and has been implemented in software for extracting the parameters of a strained-Si MOSFET.
基金Project supported by National Ministries and Commissions(Grant Nos.51308040203 and 6139801)the Fundamental Research Funds for the Central Universities,China(Grant Nos.72105499 and 72104089)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2010JQ8008)
文摘An analytical expression for the co/lector resistance of a novel vertical SiGe heterojunction bipolar transistor （HBT） on thin film silicon-on-insulator （SOI） is obtained with the substrate bias effects being considered. The resistance is found to decrease slowly and then quickly and to have kinks with the increase of the substrate-collector bias, which is quite different from that of a conventional bulk HBT. The model is consistent with the simulation result and the reported data and is useful to the frequency characteristic design of 0.13 μtm millimeter-wave SiGe SOI BiCMOS devices.
基金Projects(51308040203,6139801)supported by the National Ministries and CommissionsProjects(72105499,72104089)supported the Fundamental Research Funds for the Central Universities,ChinaProject(2010JQ8008)supported by the Natural Science Basic Research Plan in Shaanxi Province,China
文摘The effect of substrate doping on the threshold voltages of buried channel pMOSFET based on strained-SiGe technology was studied.By physically deriving the models of the threshold voltages,it is found that the layer which inversely occurs first is substrate doping dependent,giving explanation for the variation of plateau observed in the C-V characteristics of this device,as the doping concentration increases.The threshold voltages obtained from the proposed model are-1.2805 V for buried channel and-2.9358 V for surface channel at a lightly doping case,and-3.41 V for surface channel at a heavily doping case,which agrees well with the experimental results.Also,the variations of the threshold voltages with several device parameters are discussed,which provides valuable reference to the designers of strained-SiGe devices.
基金supported by the Science Foundation of National Ministries and Commissions (Grant Nos. 51308040203 and 6139801)the Fundamental Research Funds for the Central Universities of China (Grant Nos. 72105499 and 72104089)the Natural Science Basic Research Program in Shaanxi Province of China (Grant No. 2010JQ8008)
文摘In this paper, we propose an analytical avalanche multiplication model for the next generation of SiGe silicon- on-insulator （SOI） heterojunction bipolar transistors （HBTs） and consider their vertical and lateral impact ionizations for the first time. Supported by experimental data, the analytical model predicts that the avalanche multiplication governed by impact ionization shows kinks and the impact ionization effect is small compared with that of the bulk HBT, resulting in a larger base-collector breakdown voltage. The model presented in the paper is significant and has useful applications in the design and simulation of the next generation of SiCe SOI BiCMOS technology.
基金Project supported by the National Defense Advance Research Foundation(No.9140A080040410DZ106)the Basic Research Program of Ministry of Education,China(No.JY10000925005)+2 种基金the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.11JK0912)the Scientific Research Foundation of Xi’an University of Science and Technology(No.2010011)the Doctoral Research Startup Fund of Xi’an University of Science and Technology(No.2010QDJ029)
文摘With RF sputtering process, Si/Si02/Ta/Ru/Ta/CoFeB/MgO/CoFeB/Ta/Ru structure has been grown on Si （100） substrate. Attempting different targets and adjusting the oxygen dose, the crystallization quality of the MgO layer is studied. The X-ray diffraction measurements demonstrate that crystal structure and crystallization quality of MgO layers are related to the type of target and concentration of oxygen in sputtering process. With the method sputtering Mg in an ambient flow of oxygen, not only the crystallization quality of a normal MgO layer with lattice constant of 0.421 nm is improved, but also a new MgO crystal with lattice constant of 0.812 nm is formed and the perpendicular magnetic anisotropy of CoFeB is enhanced. Also it is found that crystallization quality for both the normal MgO and new MgO is more improved with MgO target and same oxygen dose, which means that this new method is helpful to form a new structure of MgO annealed at 400 ℃ in vacuum. with lattice constant of 0.812 nm. All of the samples were
