Models of threshold voltage and subthreshold swing, including the fringing-capacitance effects between the gate electrode and the surface of the source/drain region, are proposed. The validity of the proposed models i...Models of threshold voltage and subthreshold swing, including the fringing-capacitance effects between the gate electrode and the surface of the source/drain region, are proposed. The validity of the proposed models is confirmed by the good agreement between the simulated results and the experimental data. Based on the models, some factors impacting the threshold voltage and subthreshold swing of a GeOI metal-oxide-semiconductor field-effect transistor（MOSFET） are discussed in detail and it is found that there is an optimum thickness of gate oxide for definite dielectric constant of gate oxide to obtain the minimum subthreshold swing. As a result, it is shown that the fringing-capacitance effect of a shortchannel GeOI MOSFET cannot be ignored in calculating the threshold voltage and subthreshold swing.展开更多
The influences of the main structure and physical parameters of the dual-gate GeOl MOSFET on the device performance are investigated by using a TCAD 2D device simulator. A reasonable value range of germanium （Ge） ch...The influences of the main structure and physical parameters of the dual-gate GeOl MOSFET on the device performance are investigated by using a TCAD 2D device simulator. A reasonable value range of germanium （Ge） channel thickness, doping concentration, gate oxide thickness and permittivity is determined by analyzing the on-state current, off-state current, short channel effect （SCE） and drain-induced barrier lowering （DIBL） effect of the GeOI MOSFET. When the channel thickness and its doping concentration are 10-18 nm and （5-9）×1017 cm-3, and the equivalent oxide thickness and permittivity of the gate dielectric are 0.8-1 nm and 15-30, respectively, excellent device performances of the small-scaled GeOI MOSFET can be achieved： on-state current of larger than 1475 μA/μm, off-state current of smaller than 0.1μA/μm, SCE-induced threshold-voltage drift of lower than 60 mV and DIBL-induced threshold-voltage drift of lower than 140 mV.展开更多
A physical model of hole mobility for germanium-on-insulator p MOSFETs is built by analyzing all kinds of scattering mechanisms, and a good agreement of the simulated results with the experimental data is achieved, co...A physical model of hole mobility for germanium-on-insulator p MOSFETs is built by analyzing all kinds of scattering mechanisms, and a good agreement of the simulated results with the experimental data is achieved, confirming the validity of this model. The scattering mechanisms involved in this model include acoustic phonon scattering, ionized impurity scattering, surface roughness scattering, coulomb scattering and the scattering caused by Ge film thickness fluctuation. The simulated results show that the coulomb scattering from the interface charges is responsible for the hole mobility degradation in the low-field regime and the surface roughness scattering limits the hole mobility in the high-field regime. In addition, the effects of some factors, e.g. temperature, doping concentration of the channel and the thickness of Ge film, on degradation of the mobility are also discussed using the model, thus obtaining a reasonable range of the relevant parameters.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.61274112)
文摘Models of threshold voltage and subthreshold swing, including the fringing-capacitance effects between the gate electrode and the surface of the source/drain region, are proposed. The validity of the proposed models is confirmed by the good agreement between the simulated results and the experimental data. Based on the models, some factors impacting the threshold voltage and subthreshold swing of a GeOI metal-oxide-semiconductor field-effect transistor（MOSFET） are discussed in detail and it is found that there is an optimum thickness of gate oxide for definite dielectric constant of gate oxide to obtain the minimum subthreshold swing. As a result, it is shown that the fringing-capacitance effect of a shortchannel GeOI MOSFET cannot be ignored in calculating the threshold voltage and subthreshold swing.
基金Project supported by the National Natural Science Foundation of China(No.61274112)
文摘The influences of the main structure and physical parameters of the dual-gate GeOl MOSFET on the device performance are investigated by using a TCAD 2D device simulator. A reasonable value range of germanium （Ge） channel thickness, doping concentration, gate oxide thickness and permittivity is determined by analyzing the on-state current, off-state current, short channel effect （SCE） and drain-induced barrier lowering （DIBL） effect of the GeOI MOSFET. When the channel thickness and its doping concentration are 10-18 nm and （5-9）×1017 cm-3, and the equivalent oxide thickness and permittivity of the gate dielectric are 0.8-1 nm and 15-30, respectively, excellent device performances of the small-scaled GeOI MOSFET can be achieved： on-state current of larger than 1475 μA/μm, off-state current of smaller than 0.1μA/μm, SCE-induced threshold-voltage drift of lower than 60 mV and DIBL-induced threshold-voltage drift of lower than 140 mV.
基金Project supported by the National Natural Science Foundation of China(Nos.61274112,61176100,61404055)
文摘A physical model of hole mobility for germanium-on-insulator p MOSFETs is built by analyzing all kinds of scattering mechanisms, and a good agreement of the simulated results with the experimental data is achieved, confirming the validity of this model. The scattering mechanisms involved in this model include acoustic phonon scattering, ionized impurity scattering, surface roughness scattering, coulomb scattering and the scattering caused by Ge film thickness fluctuation. The simulated results show that the coulomb scattering from the interface charges is responsible for the hole mobility degradation in the low-field regime and the surface roughness scattering limits the hole mobility in the high-field regime. In addition, the effects of some factors, e.g. temperature, doping concentration of the channel and the thickness of Ge film, on degradation of the mobility are also discussed using the model, thus obtaining a reasonable range of the relevant parameters.
