As the channel length of metal-oxide-semiconductor field-effect transistors （MOSFETs） scales into the nanometer regime, quantum mechanical effects are becoming more and more significant. In this work, a model for th...As the channel length of metal-oxide-semiconductor field-effect transistors （MOSFETs） scales into the nanometer regime, quantum mechanical effects are becoming more and more significant. In this work, a model for the surrounding-gate （SG） nMOSFET is developed. The SchrSdinger equation is solved analytically. Some of the solutions are verified via results obtained from simulations. It is found that the percentage of the electrons with lighter conductivity mass increases as the silicon body radius decreases, or as the gate voltage reduces, or as the temperature decreases. The eentroid of inversion-layer is driven away from the silicon-oxide interface towards the silicon body, therefore the carriers will suffer less scattering from the interface and the electrons effective mobility of the SG nMOSFETs will be enhanced.展开更多
Emerging quantum dots(QDs)based light-emitting field-effect transistors(QLEFETs)could generate light emission with high color purity and provide facile route to tune optoelectronic properties at a low fabrication cost...Emerging quantum dots(QDs)based light-emitting field-effect transistors(QLEFETs)could generate light emission with high color purity and provide facile route to tune optoelectronic properties at a low fabrication cost.Considerable efforts have been devoted to designing device structure and to understanding the underlying physics,yet the overall performance of QLEFETs remains low due to the charge/exciton loss at the interface and the large band offset of a QD layer with respect to the adjacent carrier transport layers.Here,we report highly efficient QLEFETs with an external quantum efficiency(EQE)of over 20%by employing a dielectric-QDs-dielectric(DQD)sandwich structure.Such DQD structure is used to control the carrier behavior by modulating energy band alignment,thus shifting the exciton recombination zone into the emissive layer.Also,enhanced radiative recombination is achieved by preventing the exciton loss due to presence of surface traps and the luminescence quenching induced by interfacial charge transfer.The DQD sandwiched design presents a new concept to improve the electroluminescence performance of QLEFETs,which can be transferred to other material systems and hence can facilitate exploitation of QDs in a new type of optoelectronic devices.展开更多
Over the past half century,the semiconductor chips have deeply influenced our everyday life through increasingly sophisticated electronic products.The central driving force underlying the remarkable evolution in semic...Over the past half century,the semiconductor chips have deeply influenced our everyday life through increasingly sophisticated electronic products.The central driving force underlying the remarkable evolution in semiconductor industry is Moore’s Law,nowadays referring to a doubling of transistor counts per chip every 18 months.Sustaining Moore’s Law is economically beneficial;while the manufacturing cost per chip has been held constant,展开更多
In this work, we studied on the boron-ions implantation, including the implant dose and post-annealing temperature on the performance of PMOS radiation field-effect transistors(RADFETs) in experimental. The possible t...In this work, we studied on the boron-ions implantation, including the implant dose and post-annealing temperature on the performance of PMOS radiation field-effect transistors(RADFETs) in experimental. The possible traps and defects induced by ions implantation in the gate-oxide and their further impacting on the sensitivity and dose range of RADFETs were analyzed qualitatively. Our devices had the dry/wet/dry sandwich gate-oxide of 420 nm thick. Different ion-implanting doses and post-annealing temperatures were carried out during the RADFETs fabrication. We built a real time auto-measurement system to realize the auto-state-switch between irradiation and read-out modes, and in-situ measurement of output voltage for ten devices in turn at once of radiation experiment. The threshold voltage, dose range and sensitivity of RADFETs were extracted and analyzed in detail. The results showed that the highest sensitivity of 229 mV/Gy achieved when the implant dose was2.2×1011 cm.2 and the post-annealing temperature was 1000°C, and the dose range of 34 Gy as well.展开更多
Transistor size is constantly being reduced to improve performance as well as power consumption. For the channel length to be reduced, the corresponding gate dielectric thickness should also be reduced. Unfortunately,...Transistor size is constantly being reduced to improve performance as well as power consumption. For the channel length to be reduced, the corresponding gate dielectric thickness should also be reduced. Unfortunately, graphene devices are more complicated due to an extra capacitance called quantum capacitance （CQ） which limits the effective gate dielectric reduction. In this work, we analyzed the effect of CQ on device-scaling issues by extracting it from scaling of the channel length of devices. In contrast to previous reports for metal-insulator- metal structures, a practical device structure was used in conjunction with direct radio-frequency field-effect transistor measurements to describe the graphene channels. In order to precisely extract device parameters, we reassessed the equivalent circuit, and concluded that the on-state model should in fact be used. By careful consideration of the underlap region, our device modeling was shown to be in good agreement with the experimental data. CQ contributions to equivalent oxide thickness were analyzed in detail for varying impurity concentrations in graphene. Finally, we were able to demonstrate that despite contributions from CQ, graphene＇s high mobility and low-voltage operation allows for ~raphene channels suitable for next generation transistors.展开更多
基金Support of Shanghai Science Foundation under Grant No.09ZR1402900 the National Science Foundation of China under Grant No.60676020 Supported in part by the Special Funds for Major State Basic Research (973 Project) under Grant No.2006CB302703
文摘As the channel length of metal-oxide-semiconductor field-effect transistors （MOSFETs） scales into the nanometer regime, quantum mechanical effects are becoming more and more significant. In this work, a model for the surrounding-gate （SG） nMOSFET is developed. The SchrSdinger equation is solved analytically. Some of the solutions are verified via results obtained from simulations. It is found that the percentage of the electrons with lighter conductivity mass increases as the silicon body radius decreases, or as the gate voltage reduces, or as the temperature decreases. The eentroid of inversion-layer is driven away from the silicon-oxide interface towards the silicon body, therefore the carriers will suffer less scattering from the interface and the electrons effective mobility of the SG nMOSFETs will be enhanced.
基金support from the National Natural Science Foundation of China(62174104,61735004,and 12174086)the National Key Research and Development Program of China(2016YFB0401702)the Shanghai Science and Technology Committee(19010500600)。
文摘Emerging quantum dots(QDs)based light-emitting field-effect transistors(QLEFETs)could generate light emission with high color purity and provide facile route to tune optoelectronic properties at a low fabrication cost.Considerable efforts have been devoted to designing device structure and to understanding the underlying physics,yet the overall performance of QLEFETs remains low due to the charge/exciton loss at the interface and the large band offset of a QD layer with respect to the adjacent carrier transport layers.Here,we report highly efficient QLEFETs with an external quantum efficiency(EQE)of over 20%by employing a dielectric-QDs-dielectric(DQD)sandwich structure.Such DQD structure is used to control the carrier behavior by modulating energy band alignment,thus shifting the exciton recombination zone into the emissive layer.Also,enhanced radiative recombination is achieved by preventing the exciton loss due to presence of surface traps and the luminescence quenching induced by interfacial charge transfer.The DQD sandwiched design presents a new concept to improve the electroluminescence performance of QLEFETs,which can be transferred to other material systems and hence can facilitate exploitation of QDs in a new type of optoelectronic devices.
文摘Over the past half century,the semiconductor chips have deeply influenced our everyday life through increasingly sophisticated electronic products.The central driving force underlying the remarkable evolution in semiconductor industry is Moore’s Law,nowadays referring to a doubling of transistor counts per chip every 18 months.Sustaining Moore’s Law is economically beneficial;while the manufacturing cost per chip has been held constant,
基金supported by the National Basic Research Program of China(Grant No.2015CB352100)
文摘In this work, we studied on the boron-ions implantation, including the implant dose and post-annealing temperature on the performance of PMOS radiation field-effect transistors(RADFETs) in experimental. The possible traps and defects induced by ions implantation in the gate-oxide and their further impacting on the sensitivity and dose range of RADFETs were analyzed qualitatively. Our devices had the dry/wet/dry sandwich gate-oxide of 420 nm thick. Different ion-implanting doses and post-annealing temperatures were carried out during the RADFETs fabrication. We built a real time auto-measurement system to realize the auto-state-switch between irradiation and read-out modes, and in-situ measurement of output voltage for ten devices in turn at once of radiation experiment. The threshold voltage, dose range and sensitivity of RADFETs were extracted and analyzed in detail. The results showed that the highest sensitivity of 229 mV/Gy achieved when the implant dose was2.2×1011 cm.2 and the post-annealing temperature was 1000°C, and the dose range of 34 Gy as well.
文摘Transistor size is constantly being reduced to improve performance as well as power consumption. For the channel length to be reduced, the corresponding gate dielectric thickness should also be reduced. Unfortunately, graphene devices are more complicated due to an extra capacitance called quantum capacitance （CQ） which limits the effective gate dielectric reduction. In this work, we analyzed the effect of CQ on device-scaling issues by extracting it from scaling of the channel length of devices. In contrast to previous reports for metal-insulator- metal structures, a practical device structure was used in conjunction with direct radio-frequency field-effect transistor measurements to describe the graphene channels. In order to precisely extract device parameters, we reassessed the equivalent circuit, and concluded that the on-state model should in fact be used. By careful consideration of the underlap region, our device modeling was shown to be in good agreement with the experimental data. CQ contributions to equivalent oxide thickness were analyzed in detail for varying impurity concentrations in graphene. Finally, we were able to demonstrate that despite contributions from CQ, graphene＇s high mobility and low-voltage operation allows for ~raphene channels suitable for next generation transistors.
