scholarly journals An analytical subthreshold current/swing model for junctionless cylindrical nanowire FETs (JLCNFETs)

2013 ◽  
Vol 26 (3) ◽  
pp. 157-173 ◽  
Author(s):  
Te-Kuang Chiang ◽  
Juin Liou
Keyword(s):  
Electron Density ◽  
Silicon Film ◽  
Three Dimensional ◽  
Oxide Thickness ◽  
Channel Length ◽  
Short Channel ◽  
Doping Density ◽  
Factor B ◽  
Subthreshold Current ◽  
Channel Effects

Based on the parabolic potential approach (PPA), scaling theory, and drift-diffusion approach (DDA) with effective band gap widening (BGW), we propose an analytical subthreshold current/swing model for junctionless (JL) cylindrical nanowire FETs (JLCNFETs). The work indicates that the electron density of Qm that is induced by the current factor b, minimum central potential Fc, min and equivalent quantum potential FQM is used to determine the subthreshold current/swing for JLCNFET. Unlike the junction-based (JB) cylindrical nanowire FETs (JBCNFETs), the subthreshold current for JLCNFET is not linearly proportional to the silicon diameter, but linearly proportional to the current factor b due to the depletion-typed operation. Apart from short-channel effects (SCEs), the quantum-mechanics effects (QMEs) are included in the model by accounting for the effective BGW, which decreases the electron density in the subthreshold regime and reduces the subthreshold current consequently. Band-to-band tunneling (BTBT) that impacts the subthreshold current is also discussed in the end of the paper. The model explicitly shows how the bulk doping density, drain bias, channel length, oxide thickness, gate workfunction, and silicon film diameter affect the subthreshold current/swing. The model is verified by its calculated results matching well with the data simulated from the three-dimensional device simulator and can be used to investigate the subthreshold current/swing for JLCNFET.

scholarly journals Threshold voltage roll-off for sub-10 nm asymmetric double gate MOSFET

2019 ◽  
Vol 9 (1) ◽  
pp. 163
Author(s):  
Hakkee Jung
Keyword(s):  
Threshold Voltage ◽  
Tunneling Current ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Channel Length ◽  
Double Gate ◽  
Short Channel ◽  
Double Gate Mosfet ◽  
Channel Effects ◽  
Channel Thickness

Threshold voltage roll-off is analyzed for sub-10 nm asymmetric double gate (DG) MOSFET. Even asymmetric DGMOSFET will increase threshold voltage roll-off in sub-10 nm channel length because of short channel effects due to the increase of tunneling current, and this is an obstacle against the miniaturization of asymmetric DGMOSFET. Since asymmetric DGMOSFET can be produced differently in top and bottom oxide thickness, top and bottom oxide thicknesses will affect the threshold voltage roll-off. To analyze this, <em>thermal</em><em> </em>emission current and tunneling current have been calculated, and threshold voltage roll-off by the reduction of channel length has been analyzed by using channel thickness and top/bottom oxide thickness as parameters. As a result, it is found that, in short channel asymmetric double gate MOSFET, threshold voltage roll-off is changed greatly according to top/bottom gate oxide thickness, and that threshold voltage roll-off is more influenced by silicon thickness. In addition, it is found that top and bottom oxide thickness have a relation of inverse proportion mutually for maintaining identical threshold voltage. Therefore, it is possible to reduce the leakage current of the top gate related with threshold voltage by increasing the thickness of the top gate oxide while maintaining the same threshold voltage.

Electrically Induced Junction MOSFET for High Performance Sub-50nm CMOS Technology

2002 ◽  
Vol 716 ◽  
Author(s):  
Abhisek Dixit ◽  
Rajiv O. Dusane ◽  
V. Ramgopal Rao
Keyword(s):  
Gate Voltage ◽  
High Performance ◽  
Oxide Thickness ◽  
Cmos Technology ◽  
Channel Length ◽  
Short Channel ◽  
Channel Effects ◽  
Deep Source ◽  
Proper Scaling ◽  
Effective Channel

AbstractDegrading of short-channel effects (SCE) e.g. Drain-Induced-Barrier-Lowering (DIBL), charge-sharing etc., as CMOS devices are scaled into the sub-50nm regime, is a major roadblock for ULSI technologies. This problem can be circumvented to some extent by a proper scaling of MOSFET vertical dimensions (junction depths, oxide thickness etc.). In this work we propose a novel implementation of an electrically induced junction (EJ) MOSFET. An EJ-MOSFET is different from conventional CMOS device in that the gate voltage electrically induces the shallow source-drain extensions (SDEs). In such a device the SDEs are underneath the gate and contain low-doped regions of opposite conductivity as that of deep source-drain (S/D). In order to turn ON the device, a voltage is applied at the gate of EJ-MOSFET device, such that these low doped regions below poly-Si gate get inverted and serve as SDEs. Consequently, the effective channel length in this condition is the distance between these low-doped regions. On the contrary, at any gate voltage less than that required for inverting these regions, no SDEs are induced, and the effective channel length is equal to the physical separation between the deep S/D junctions.

Influence of Channel Length and High-K Oxide Thickness on Subthreshold DC Performance of Graded Channel and Gate Stack DG-MOSFETs

NANO ◽  
2016 ◽  
Vol 11 (09) ◽  
pp. 1650101 ◽  
Author(s):  
Sarosij Adak ◽  
Sanjit Kumar Swain ◽  
Arka Dutta ◽  
Hafizur Rahaman ◽  
Chandan Kumar Sarkar
Keyword(s):  
High Speed ◽  
Oxide Thickness ◽  
Channel Length ◽  
Gate Stack ◽  
Short Channel ◽  
Power Circuit ◽  
Novel Device ◽  
High K ◽  
Channel Effects ◽  
High Speed Switching

Comparative assessment of graded channel gate stack (GCGS) DG MOSFET structure is done by using two-dimensional (2D) Sentrausu TCAD simulator for different high K oxide thickness. This novel device includes gate stack (GS) engineering (high K) and nonuniformly channel engineering (GC) to suppress the short channel effects and improve the device performance. This novel device can be a better alternative for the future high speed switching and low power circuit applications. It has the advantage of improved breakdown voltage, reduced leakage current, low output conductance and reduced bipolar parasitic effects. The given device must be properly investigated with respect to the variation of different high K oxide thickness on different parameters such as drain induced barrier lowering (DIBL), subthreshold slope (SS), [Formula: see text]/[Formula: see text], [Formula: see text] roll off before fabrication to have better reliability. The 2D Sentrausu TCAD simulator using drift-diffusion model was used to simulate the developed structure and good agreement is obtained with respect to already published result in the sub-threshold regime. The result indicates that there is a need to be optimize the DC parameters for specific circuit applications.

Projected Performance of Sub-10 nm GaN-based Double Gate MOSFETs

2017 ◽  
Vol 2 (2) ◽  
pp. 15-19 ◽  
Author(s):  
Md. Saud Al Faisal ◽  
Md. Rokib Hasan ◽  
Marwan Hossain ◽  
Mohammad Saiful Islam
Keyword(s):  
High Speed ◽  
Field Effect Transistors ◽  
Cmos Technology ◽  
Channel Length ◽  
Capacitive Coupling ◽  
Oxide Semiconductor ◽  
Double Gate ◽  
Short Channel ◽  
Channel Effects ◽  
Silvaco Atlas

GaN-based double gate metal-oxide semiconductor field-effect transistors (DG-MOSFETs) in sub-10 nm regime have been designed for the next generation logic applications. To rigorously evaluate the device performance, non-equilibrium Green’s function formalism are performed using SILVACO ATLAS. The device is turn on at gate voltage, VGS =1 V while it is going to off at VGS = 0 V. The ON-state and OFF-state drain currents are found as 12 mA/μm and ~10-8 A/μm, respectively at the drain voltage, VDS = 0.75 V. The sub-threshold slope (SS) and drain induced barrier lowering (DIBL) are ~69 mV/decade and ~43 mV/V, which are very compatible with the CMOS technology. To improve the figure of merits of the proposed device, source to gate (S-G) and gate to drain (G-D) distances are varied which is mentioned as underlap. The lengths are maintained equal for both sides of the gate. The SS and DIBL are decreased with increasing the underlap length (LUN). Though the source to drain resistance is increased for enhancing the channel length, the underlap architectures exhibit better performance due to reduced capacitive coupling between the contacts (S-G and G-D) which minimize the short channel effects. Therefore, the proposed GaN-based DG-MOSFETs as one of the excellent promising candidates to substitute currently used MOSFETs for future high speed applications.

scholarly journals Impact of device scaling on the electrical properties of MoS2 field-effect transistors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Goutham Arutchelvan ◽  
Quentin Smets ◽  
Devin Verreck ◽  
Zubair Ahmed ◽  
Abhinav Gaur ◽  
...  
Keyword(s):  
Field Effect Transistors ◽  
Oxide Thickness ◽  
Channel Length ◽  
Contact Length ◽  
Power Performance ◽  
Semiconducting Materials ◽  
Large Area ◽  
Short Channel ◽  
Device Scaling ◽  
Performance Area

AbstractTwo-dimensional semiconducting materials are considered as ideal candidates for ultimate device scaling. However, a systematic study on the performance and variability impact of scaling the different device dimensions is still lacking. Here we investigate the scaling behavior across 1300 devices fabricated on large-area grown MoS2 material with channel length down to 30 nm, contact length down to 13 nm and capacitive effective oxide thickness (CET) down to 1.9 nm. These devices show best-in-class performance with transconductance of 185 μS/μm and a minimum subthreshold swing (SS) of 86 mV/dec. We find that scaling the top-contact length has no impact on the contact resistance and electrostatics of three monolayers MoS2 transistors, because edge injection is dominant. Further, we identify that SS degradation occurs at short channel length and can be mitigated by reducing the CET and lowering the Schottky barrier height. Finally, using a power performance area (PPA) analysis, we present a roadmap of material improvements to make 2D devices competitive with silicon gate-all-around devices.

scholarly journals The Effect of Doping on Different FET Structures: MOSFET, TFET and FinFET

2020 ◽  
Vol 9 (6) ◽  
pp. 972-979
Keyword(s):  
Drain Current ◽  
Channel Length ◽  
Short Channel Effects ◽  
Poor Control ◽  
Short Channel ◽  
Circuit Performance ◽  
The Past ◽  
Channel Effects ◽  
Circuit Density ◽  
Effect Of Doping

MOSFET have been scaled down over the past few years in order to give rise to high circuit density and increase the speed of circuit. But scaling of MOSFET leads to issues such as poor control gate over the current which depends on gate voltage. Many short channel effects (SCE) influence the circuit performance and leads to the indeterminist response of drain current. These effects can be decreased by gate excitation or by using multiple gates and by offering better control gate the device parameters. In Single gate MOSFET, gate electric field decreases but multigate MOSFET or FinFET provides better control over drain current. In this paper, different FET structures such as MOSFET, TFET and FINFET are designed at 22nm channel length and effect of doping had been evaluated and studied. To evaluate the performance donor concentration is kept constant and acceptor concentration is varied.

Modeling and Designing a Device Using MuGFETs

2008 ◽  
Author(s):  
V. K. Lamba ◽  
Derick Engles ◽  
S. S. Malik
Keyword(s):  
Gate Dielectric ◽  
Silicon Film ◽  
General Rule ◽  
Channel Length ◽  
Silicon On Insulator ◽  
Oxide Semiconductor ◽  
Radius Of Curvature ◽  
Short Channel ◽  
Dielectric Thickness ◽  
Fin Thickness

This work describes computer simulations of various, Silicon on Insulator (SOI) Metal Oxide Semiconductor Field Effect Transistor (MOSFETs) with double and triple-gate structures, as well as gate-all-around devices. To explore the optimum design space for four different gate structures, simulations were performed with four variable device parameters: gate length, channel width, doping concentration, and silicon film thickness. The efficiency of the different gate structures is shown to be dependent of these parameters. Here short-channel properties of multi-gate SOI MOSFETs (MuGFETs) are studied by numerical simulation. The evolution of characteristics such as Drain induced barrier lowering (DIBL), sub-threshold slope, and threshold voltage roll-off is analyzed as a function of channel length, silicon film or fin thickness, gate dielectric thickness and dielectric constant, and as a function of the radius of curvature of the corners. The notion of an equivalent gate number is introduced. As a general rule, increasing the equivalent gate number improves the short-channel behavior of the devices. Similarly, increasing the radius of curvature of the corners improves the control of the channel region by the gate.

scholarly journals Comparative Simulation Analysis of Process Parameter Variations in 20 nm Triangular FinFET

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Satyam Shukla ◽  
Sandeep Singh Gill ◽  
Navneet Kaur ◽  
H. S. Jatana ◽  
Varun Nehru
Keyword(s):  
Process Parameters ◽  
Simulation Analysis ◽  
Oxide Thickness ◽  
Channel Length ◽  
Deep Submicron ◽  
Device Structure ◽  
Short Channel ◽  
20 Nm ◽  
The Impact ◽  
Fin Shape

Technology scaling below 22 nm has brought several detrimental effects such as increased short channel effects (SCEs) and leakage currents. In deep submicron technology further scaling in gate length and oxide thickness can be achieved by changing the device structure of MOSFET. For 10–30 nm channel length multigate MOSFETs have been considered as most promising devices and FinFETs are the leading multigate MOSFET devices. Process parameters can be varied to obtain the desired performance of the FinFET device. In this paper, evaluation of on-off current ratio (Ion/Ioff), subthreshold swing (SS) and Drain Induced Barrier Lowering (DIBL) for different process parameters, that is, doping concentration (1015/cm3 to 1018/cm3), oxide thickness (0.5 nm and 1 nm), and fin height (10 nm to 40 nm), has been presented for 20 nm triangular FinFET device. Density gradient model used in design simulation incorporates the considerable quantum effects and provides more practical environment for device simulation. Simulation result shows that fin shape has great impact on FinFET performance and triangular fin shape leads to reduction in leakage current and SCEs. Comparative analysis of simulation results has been investigated to observe the impact of process parameters on the performance of designed FinFET.

Sign in / Sign up

Export Citation Format

Share Document