Large threshold voltage and small on-state current are the main limitations of the normal tunneling field effect transistor (TFET). In this paper, a novel TFET with gate-controlled P+N+N+ structure based on partially ...Large threshold voltage and small on-state current are the main limitations of the normal tunneling field effect transistor (TFET). In this paper, a novel TFET with gate-controlled P+N+N+ structure based on partially depleted GeOI (PD-GeOI) substrate is proposed. With the buried P+-doped layer (BP layer) introduced under P+N+N+ structure, the proposed device behaves as a two-tunneling line device and can be shut off by the BP junction, resulting in a high on-state current and low threshold voltage. Simulation results show that the on-state current density Ion of the proposed TFET can be as large as 3.4 × 10^−4 A/μm, and the average subthreshold swing (SS) is 55 mV/decade. Moreover, both of Ion and SS can be optimized by lengthening channel and buried P+ layer. The off-state current density of TTP TFET is 4.4 × 10^−10 A/μm, and the threshold voltage is 0.13 V, showing better performance than normal germanium-based TFET. Furthermore, the physics and device design of this novel structure are explored in detail.展开更多
This paper proposes a new two dimensional（2D） analytical model for a germanium（Ge） single gate silicon-on-insulator tunnel field effect transistor（SG SOI TFET）. The parabolic approximation technique is used to s...This paper proposes a new two dimensional（2D） analytical model for a germanium（Ge） single gate silicon-on-insulator tunnel field effect transistor（SG SOI TFET）. The parabolic approximation technique is used to solve the 2D Poisson equation with suitable boundary conditions and analytical expressions are derived for the surfacepotential,theelectricfieldalongthechannelandtheverticalelectricfield.Thedeviceoutputtunnellingcurrent is derived further by using the electric fields. The results show that Ge based TFETs have significant improvements inon-currentcharacteristics.Theeffectivenessoftheproposedmodelhasbeenverifiedbycomparingtheanalytical model results with the technology computer aided design（TCAD） simulation results and also comparing them with results from a silicon based TFET.展开更多
A dielectric modulation strategy for gate oxide material that enhances the sensing performance of biosensors in junction-less vertical tunnel field effect transistors(TFETs)is reported.The junction-less technique,in w...A dielectric modulation strategy for gate oxide material that enhances the sensing performance of biosensors in junction-less vertical tunnel field effect transistors(TFETs)is reported.The junction-less technique,in which metals with specific work functions are deposited on the source region to modulate the channel conductivity,is used to provide the necessary doping for the proper functioning of the device.TCAD simulation studies of the proposed structure and junction structure have been compared,and showed an enhanced rectification of 10^(4) times.The proposed structure is designed to have a nanocavity of length 10 nm on the left-and right-hand sides of the fixed gate dielectric,which improves the biosensor capture area,and hence the sensitivity.By considering neutral and charged biomolecules with different dielectric constants,TCAD simulation studies were compared for their sensitivities.The off-state current IOFFcan be used as a suitable sensing parameter because it has been observed that the proposed sensor exhibits a significant variation in drain current.Additionally,it has been investigated how positively and negatively charged biomolecules affect the drain current and threshold voltage.To explore the device performance when the nanogaps are fully filled,half filled and unevenly filled,extensive TCAD simulations have been run.The proposed TFET structure is further benchmarked to other structures to show its better sensing capabilities.展开更多
To solve the problem of the low on-state current in p-type tunnel field-effect transistors(p-TFETs),this paper analyzes the mechanism of adjusting the tunneling current of a TFET device determined by studying the infl...To solve the problem of the low on-state current in p-type tunnel field-effect transistors(p-TFETs),this paper analyzes the mechanism of adjusting the tunneling current of a TFET device determined by studying the influence of the peak position of ion implantation on the potential of the p-TFET device surface and the width of the tunneling barrier.Doping-regulated silicon-based high on-state p-TFET devices are designed and fabricated,and the test results show that the on-state current of the fabricated devices can be increased by about two orders of magnitude compared with the current of other devices with the same structure.This method provides a new idea for the realization of high on-state current TFET devices.展开更多
The fundamental advantages of carbon-based graphene material,such as its high tunnelling probability,symmetric band structure(linear dependence of the energy band on the wave direction),low effective mass,and characte...The fundamental advantages of carbon-based graphene material,such as its high tunnelling probability,symmetric band structure(linear dependence of the energy band on the wave direction),low effective mass,and characteristics of its 2D atomic layers,are the main focus of this research work.The impact of channel thickness,gate under-lap,asymmetric source/drain doping method,workfunction of gate contact,and High-K material on Graphene-based Tunnel Field Effect Transistor(TFET)is analyzed with 20 nm technology.Physical modelling and electrical characteristic performance have been simulated using the Atlas device simulator of SILVACO TCAD with user-defined material syntax for the newly included graphene material in comparison to silicon carbide(SiC).The simulation results in significant suppression of ambipolar current to voltage characteristics of TFET and modelled device exhibits a significant improvement in subthreshold swing(0.0159 V/decade),the ratio of Ion/Ioff(1000),and threshold voltage(-0.2 V with highly doped p-type source and 0.2 V with highly doped n-type drain)with power supply of 0.5 V,which make it useful for low power digital applications.展开更多
研究了一种新型非对称栅隧穿场效应晶体管(AG-TFET),新型结构结合了隧穿场效应晶体管陡峭的亚阈值摆幅与无结器件较大的开态电流的优点,其总电流大小受控于底部沟道势垒和p+区与本征沟道区形成的反偏p-i隧穿结处的带隙宽度以及电场强度...研究了一种新型非对称栅隧穿场效应晶体管(AG-TFET),新型结构结合了隧穿场效应晶体管陡峭的亚阈值摆幅与无结器件较大的开态电流的优点,其总电流大小受控于底部沟道势垒和p+区与本征沟道区形成的反偏p-i隧穿结处的带隙宽度以及电场强度。使用Silvaco TCAD软件对器件性能进行了仿真,并对p+区厚度以及底栅栅介质二氧化铪的长度进行了优化。仿真结果表明:新型AG-TFET具有良好的电学特性,在室温下开关电流比可以达到3.3×1010,开态电流为302μA/μm,陡峭的亚阈值摆幅即点亚阈值摆幅为35 m V/dec,平均亚阈值摆幅为54 m V/dec。因此,该新型AG-TFET有望被应用在未来低功耗电路中。展开更多
Trap-assisted tunneling（TAT） has attracted more and more attention, because it seriously affects the sub-threshold characteristic of tunnel field-effect transistor（TFET）. In this paper, we assess subthreshold perf...Trap-assisted tunneling（TAT） has attracted more and more attention, because it seriously affects the sub-threshold characteristic of tunnel field-effect transistor（TFET）. In this paper, we assess subthreshold performance of double gate TFET（DG-TFET） through a band-to-band tunneling（BTBT） model, including phonon-assisted scattering and acoustic surface phonons scattering. Interface state density profile（D_（it）） and the trap level are included in the simulation to analyze their effects on TAT current and the mechanism of gate leakage current.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61704130)the Science Research Plan in Shaanxi Province,China(Grant No.2018JQ6064)the Science and Technology Project on Analog Integrated Circuit Laboratory,China(Grant No.JCKY2019210C029).
文摘Large threshold voltage and small on-state current are the main limitations of the normal tunneling field effect transistor (TFET). In this paper, a novel TFET with gate-controlled P+N+N+ structure based on partially depleted GeOI (PD-GeOI) substrate is proposed. With the buried P+-doped layer (BP layer) introduced under P+N+N+ structure, the proposed device behaves as a two-tunneling line device and can be shut off by the BP junction, resulting in a high on-state current and low threshold voltage. Simulation results show that the on-state current density Ion of the proposed TFET can be as large as 3.4 × 10^−4 A/μm, and the average subthreshold swing (SS) is 55 mV/decade. Moreover, both of Ion and SS can be optimized by lengthening channel and buried P+ layer. The off-state current density of TTP TFET is 4.4 × 10^−10 A/μm, and the threshold voltage is 0.13 V, showing better performance than normal germanium-based TFET. Furthermore, the physics and device design of this novel structure are explored in detail.
文摘This paper proposes a new two dimensional（2D） analytical model for a germanium（Ge） single gate silicon-on-insulator tunnel field effect transistor（SG SOI TFET）. The parabolic approximation technique is used to solve the 2D Poisson equation with suitable boundary conditions and analytical expressions are derived for the surfacepotential,theelectricfieldalongthechannelandtheverticalelectricfield.Thedeviceoutputtunnellingcurrent is derived further by using the electric fields. The results show that Ge based TFETs have significant improvements inon-currentcharacteristics.Theeffectivenessoftheproposedmodelhasbeenverifiedbycomparingtheanalytical model results with the technology computer aided design（TCAD） simulation results and also comparing them with results from a silicon based TFET.
文摘A dielectric modulation strategy for gate oxide material that enhances the sensing performance of biosensors in junction-less vertical tunnel field effect transistors(TFETs)is reported.The junction-less technique,in which metals with specific work functions are deposited on the source region to modulate the channel conductivity,is used to provide the necessary doping for the proper functioning of the device.TCAD simulation studies of the proposed structure and junction structure have been compared,and showed an enhanced rectification of 10^(4) times.The proposed structure is designed to have a nanocavity of length 10 nm on the left-and right-hand sides of the fixed gate dielectric,which improves the biosensor capture area,and hence the sensitivity.By considering neutral and charged biomolecules with different dielectric constants,TCAD simulation studies were compared for their sensitivities.The off-state current IOFFcan be used as a suitable sensing parameter because it has been observed that the proposed sensor exhibits a significant variation in drain current.Additionally,it has been investigated how positively and negatively charged biomolecules affect the drain current and threshold voltage.To explore the device performance when the nanogaps are fully filled,half filled and unevenly filled,extensive TCAD simulations have been run.The proposed TFET structure is further benchmarked to other structures to show its better sensing capabilities.
基金Project supported by the Key Research and Development Program of Shaanxi(Grant No.2021GY-010)the National Defense Science and Technology Foundation Strengthening Program of China(Grant No.2019-XXXX-XX-236-00).
文摘To solve the problem of the low on-state current in p-type tunnel field-effect transistors(p-TFETs),this paper analyzes the mechanism of adjusting the tunneling current of a TFET device determined by studying the influence of the peak position of ion implantation on the potential of the p-TFET device surface and the width of the tunneling barrier.Doping-regulated silicon-based high on-state p-TFET devices are designed and fabricated,and the test results show that the on-state current of the fabricated devices can be increased by about two orders of magnitude compared with the current of other devices with the same structure.This method provides a new idea for the realization of high on-state current TFET devices.
文摘The fundamental advantages of carbon-based graphene material,such as its high tunnelling probability,symmetric band structure(linear dependence of the energy band on the wave direction),low effective mass,and characteristics of its 2D atomic layers,are the main focus of this research work.The impact of channel thickness,gate under-lap,asymmetric source/drain doping method,workfunction of gate contact,and High-K material on Graphene-based Tunnel Field Effect Transistor(TFET)is analyzed with 20 nm technology.Physical modelling and electrical characteristic performance have been simulated using the Atlas device simulator of SILVACO TCAD with user-defined material syntax for the newly included graphene material in comparison to silicon carbide(SiC).The simulation results in significant suppression of ambipolar current to voltage characteristics of TFET and modelled device exhibits a significant improvement in subthreshold swing(0.0159 V/decade),the ratio of Ion/Ioff(1000),and threshold voltage(-0.2 V with highly doped p-type source and 0.2 V with highly doped n-type drain)with power supply of 0.5 V,which make it useful for low power digital applications.
文摘研究了一种新型非对称栅隧穿场效应晶体管(AG-TFET),新型结构结合了隧穿场效应晶体管陡峭的亚阈值摆幅与无结器件较大的开态电流的优点,其总电流大小受控于底部沟道势垒和p+区与本征沟道区形成的反偏p-i隧穿结处的带隙宽度以及电场强度。使用Silvaco TCAD软件对器件性能进行了仿真,并对p+区厚度以及底栅栅介质二氧化铪的长度进行了优化。仿真结果表明:新型AG-TFET具有良好的电学特性,在室温下开关电流比可以达到3.3×1010,开态电流为302μA/μm,陡峭的亚阈值摆幅即点亚阈值摆幅为35 m V/dec,平均亚阈值摆幅为54 m V/dec。因此,该新型AG-TFET有望被应用在未来低功耗电路中。
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61574109 and 61204092)
文摘Trap-assisted tunneling（TAT） has attracted more and more attention, because it seriously affects the sub-threshold characteristic of tunnel field-effect transistor（TFET）. In this paper, we assess subthreshold performance of double gate TFET（DG-TFET） through a band-to-band tunneling（BTBT） model, including phonon-assisted scattering and acoustic surface phonons scattering. Interface state density profile（D_（it）） and the trap level are included in the simulation to analyze their effects on TAT current and the mechanism of gate leakage current.
