Impact of strained silicon on the device performance of a bipolar charge plasma transistor

In this manuscript we analyze a unique approach to improve the performance of the bipolar charge plasma transistor(BCPT) by introducing a strained Si/SiGe1-x layer as the active device region. For charge plasma realization different metal work-function electrodes are used to induce n+ and p+ regions on undoped strained silicon-on-insulator(sSOI or SiGe) to realize emitter, base, and collector regions of the BCPT. Here,by using a calibrated 2-D TCAD simulation the impact of a Si mole fraction x(in SiGe) on device performance metrics is investigated. The analysis demonstrates the band gap lowering with decreasing Si content or effective strain on the Si layer, and its subsequent advantages. This work reports a significant improvement in current gain, cutoff frequency, and lower collector breakdown voltage(BVCEO) for the proposed structure over the conventional device. The effect of varying temperature on the strained Si layer and its implications on the device performance is also investigated. The analysis demonstrates a fair device-level understanding and exhibits the immense potential of the SiGematerial as the device layer. In addition to this, using extensive 2-D mixed-mode TCAD simulation, a considerable improvement in switching transient times are also observed compared to its conventional counterpart.

Performance analysis of charge plasma based dual electrode tunnel FET

This paper proposes the charge plasma based dual electrode doping-less tunnel FET （DEDLTFET）. The paper compares the device performance of the conventional doping-less TFET （DLTFET） and doped TFET （DGTFET）. DEDLTEFT gives the superior results with high ON state current （/ON - 0.56 mA/um）, ION/IoFv ratio - 9.12 ×1013 and an average subthreshold swing （AV-SS -- 48 mV/dec）. The variation of different device parameters such as channel length, gate oxide material, gate oxide thickness, silicon thickness, gate work function and temperature variation are done and compared with DLTFET and DGTFET. Through the extensive analysis it is found that DEDLTFET shows the better performance than the other two devices, which gives the indication for an excellent future in low power applications.

Resistance and Reactance of Monopole Fields Induced by a Test Charge Drifting Off-Axis in a Cold and Collisional Cylindrical Plasma

We study the interaction of a uniform, cold and collisional plasma with a test charged particle moving off-axis at a constant speed down a cylindrical tube with a resistive thick metallic wall. Upon matching the electromagnetic field components at all interfaces, the induced monopole electromagnetic fields in the plasma are obtained in the frequency domain. An expression for the plasma electric resistance and reactance is derived and analyzed numerically for some representative parameters. Near the plasma resonant frequency, the plasma resistance evolves with frequency like a parallel RLC resonator with peak resistance at the plasma frequency pe, while the plasma reactance can be capacitive or inductive in nature depending on the frequency under consideration.

Effects of a liquid lithium curtain as the first wall in a fusion reactor plasma

This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder （FEB-E）. The relationships between the surface temperature of a liquid lithium curtain and the effective plasma charge, fuel dilution and fusion power production have been derived. Results indicate that under normal operation, the evaporation of liquid lithium does not seriously affect the effective plasma charge, but effects on fuel dilution and fusion power are more sensitive. As an example, it has investigated the relationships between the liquid lithium curtain flow velocity and the rise of surface temperature based on operation scenario II of the FEB-E design with reversed shear configuration and high power density. Results show that even if the liquid lithium curtain flow velocity is as low as 0.5 m/s, the effects of evaporation from the liquid lithium curtain on plasma are negligible. In the present design, the sputtering of liquid lithium curtain and the particle removal effects of the divertor are not yet considered in detail. Further studies are in progress, and in this work implication of lithium erosion and divertor physics on fusion reactor operation are discussed.

Spatial charge and compensation method in a whirler

Based on particle-in-cell simulation, we studied the motions of ions and electrons. The results have shown that electrons are bounded by a magnetic field and only a small number of electrons can pass through the whirler channel. The plasma becomes non-neutral when it is emitted from the whirler, and the spatial charge leads to a beam divergence, which is unfavorable for mass separation. In order to compensate the spatial charge, a cathode is designed to transmit electrons and the quasi-neutral plasma beam. Experiment results have demonstrated that the auxiliary cathode can obviously improve the compensation degree of the spatial charge.

兼具高电流增益和高击穿性能的电荷等离子体双极晶体管

为了兼顾高电流增益β和发射极开路集电结的高击穿电压V_(CBO)与基极开路集电极-发射极间的高击穿电压V_(CEO),有效提升电荷等离子体双极晶体管(bipolar charge plasma transistor,BCPT)的高压大电流处理能力,利用SILVACO TCAD建立了npn型BCPT的器件模型。考虑到双极晶体管的击穿电压主要取决于集电区掺杂浓度,首先研究了集电极金属对BCPT性能的影响。分析表明,BCPT集电区的电子浓度强烈依赖于电极金属的功函数,当采用功函数较大的铝(Al)作为集电极金属时,由于减小了金属-半导体接触的功函数差,降低了集电区中诱导产生的电子等离子体浓度,从而有效降低了集电结空间电荷区峰值电场强度,减小了峰值电子温度以及峰值电子碰撞电离率,因此,达到改善击穿电压V_(CBO)和V_(CEO)的目的。然而,集电区电子浓度的减小会引起基区Kirk效应,增大基区复合,降低β。为此,进一步提出了一种采用衬底偏压结构的BCPT,通过在发射区和基区下方引入正衬底偏压,调制发射区和基区有效载流子浓度,达到提高发射结注入效率、增大β的目的。结果表明:与仅采用锆(Zr)作为集电极金属的BCPT相比,该器件的峰值电流增益改善了21.69%,击穿电压V_(CBO)和V_(CEO)分别改善了12.78%和56.41%,从而有效扩展了BCPT的高功率应用范围。

Design and investigation of doping-less gate-all-around TFET with Mg_(2)Si source material for low power and enhanced performance applications

Metal–oxide–semiconductor field-effect transistor(MOSFET)faces the major problem of being unable to achieve a subthreshold swing(SS)below 60 mV/dec.As device dimensions continue to reduce and the demand for high switching ratios for low power consumption increases,the tunnel field-effect transistor(TFET)appears to be a viable device,displaying promising characteristic as an answer to the shortcomings of the traditional MOSFET.So far,TFET designing has been a task of sacrificing higher ON state current for low subthreshold swing(and vice versa),and a device that displays both while maintaining structural integrity and operational stability lies in the nascent stages of popular research.This work presents a comprehensive analysis of a heterojunction plasma doped gate-all-around TFET(HPD-GAA-TFET)by making a comparison between Mg_(2)Si and Si which serve as source materials.Charge plasma technique is employed to implement doping in an intrinsic silicon wafer with the help of suitable electrodes.A low-energy bandgap material,i.e.magnesium silicide is incorporated as source material to form a heterojunction between source and silicon-based channel.A rigorous comparison of performance between Si-based GAA-TFET and HPD-GAA-TFET is conducted in terms of electrical,radio frequency(RF),linearity,and distortion parameters.It is observable that HPD-GAA-TFET outperforms conventional Si-based GAA-TFET with an ON-state current(I_(ON)),subthreshold swing(SS),threshold voltage(V_(th)),and current switching ratio being 0.377 mA,12.660 mV/dec,0.214 V,and 2.985×10^(12),respectively.Moreover,HPD-GAA-TFET holds faster switching and is more reliable than Si-based device.Therefore,HPD-GAA-TFET is suitable for low-power applications.

Deposition of SiCxHyOz thin film on epoxy resin by nanosecond pulsed APPJ for improving the surface insulating performance

Non-thermal plasma surface modification for epoxy resin（EP）to improve the insulation properties has wide application prospects in gas insulated switchgear and gas insulatedtransmission line.In this paper,a pulsed Ar dual dielectrics atmospheric-pressure plasma jet（APPJ）was used for Si CxHyOzthin film deposition on EP samples.The film deposition was optimized by varying the treatment time while other parameters were kept at constants（treatment distance：10 mm,precursor flow rate：0.6 l min-（-1）,maximum instantaneous power：3.08 k W and single pulse energy：0.18 m J）.It was found that the maximum value of flashover voltages for negative and positive voltage were improved by 18%and 13%when the deposition time was3 min,respectively.The flashover voltage reduced as treatment time increased.Moreover,all the surface conductivity,surface charge dissipation rate and surface trap level distribution reached an optimal value when thin film deposition time was 3 min.Other measurements,such as atomic force microscopy and scanning electron microscope for EP surface morphology,Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy for EP surface compositions,optical emission spectra for APPJ deposition process were carried out to better understand the deposition processes and mechanisms.The results indicated that the original organic groups（C–H,C–C,C=O,C=C）were gradually replaced by the Si containing inorganic groups（Si–O–Si and Si–OH）.The reduction of C=O in ester group and C=C in p-substituted benzene of the EP samples might be responsible for shallowing the trap level and then enhancing the flashover voltage.However,when the plasma treatment time was longer than 3 min,the significant increase of the surface roughness might increase the trap level depth and then deteriorate the flashover performance.

Potential distribution around a test charge in a positive dust-electron plasma

The electrostatic potential caused by a test-charge particle in a positive dust-electron plasma is studied, accounting for the d^Lst-charge fluctuations associated with ultraviolet photoelectron and thermionic emissions. For this purpose, the set of Vlasov-Poisson equations coupled with the dust charging equation is solved by using the space-time Fourier transform technique. As a consequence, a modified dielectric response function is obtained for dust-acoustic waves in a positive dust-electron plasma. By imposing certain conditions on the velocity of the test charge, the electrostatic potential is decomposed into the Deby^Hiickel （DH）, wake-field （WF）, and far-field （FF） potentials that are significantly modified in the limit of a large dust-charge relaxation rate both analytically and numerically. The results can be helpful for understanding dust crystallization/coagulation in two- component plasmas, where positively charged dust grains are present.

solitary waves shock waves dust charge variation dusty plasma

The nonlinear propagation of dust acoustic waves is investigated in four-component plasmas consisting of positively charged dust grains, trapped ions, nonthermal electrons, and photoelectron due to ultraviolet irradiation.We use generalized viscoelastic hydrodynamic model for strongly coupled dust grain. In the weak nonlinearity limit, a modified Kadomstev–Petviashvili（KP） equation and a modified KP-Burger equation, which have a damping term coming from nonadiabatic charge variation, have been derived in the kinetic regime and hydrodynamic regime, respectively. With the increasing of UV photon flux, the hydrodynamic regime changes to kinetic regime. The approximate analytical line soliton and shock solutions are investigated in the kinetic regime and hydrodynamic regime, respectively.