Designing of Tunnel FET and FinFET using Sentaurus TCAD and Finding their Characteristics

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There are a lot of new technologies booming in the recent years.The MOSFET's are now slowly replaced by other FET devices, such as Tunnel-FET (TFET) and FinFET [1] [2].TFET and FinFET have better performance than MOSFET in low power supply devices in most cases.FinFET is basically a Multi-gate MOSFET structure.On scaling the MOS-FET, the size is reduced to 100 nm variation, due to which subthreshold-Swing has increased, and I-off current has also increased.Which is why, we are approaching alternate technologies.In MOSFET, limiting the subthreshold swing to 60mV/decade due to thermal Boltzmann tail of carries, whereas it does not affect the TFET devices [3] [4].
On restricting the Size of the MOSFET, it results in the increase of large Short Channel effects.Whereas, TFET works well in this scenario and shows better performance using Quantum-Tunneling effect.There are many\different types of devices\in FinFET and\TFET, including\single-gate FinFET, double-gate\FinFET, triple-gate\FinFET, and\many more [6].A planar TFET has higher electric field effect, has better ON current and decreased subthreshold-swing than other TFET devices.There are many drawbacks to this device's also, In TFET, the ON current is very less and there are ambipolar effects.Whereas in FinFET, it has high parasitic capacitances, it's hard to manage the varying Threshold voltage (Vth).Both of them put to gather, have high fabricating cost compared to that of MOSFET.
While modelling the device, the structures are placed on Silicon on Insulator (SOI) to avoid any sort of leakage.There are two different types of device modelling such as 2D and 3D, which will result in analyzing the various structures.These devices are modelled in Sentaurus TCAD software for further analyzes.TCAD allows to study the device structure and various other parameter in the Software.FinFET has vertical channel which looks like a fin, whereas, MOSFET has a horizontal channel.In FIN-FET the channel is covered with a Silicon layer.The TFET device has-P-I-Njunction, and-works-on-the band-to band Tunneling.On giving some bias to drain, the conduction band of the channel is shoved below the valence band of the source part.
Website: www.ijeer.forexjournal.co.inDesigning of Tunnel FET and FinFET using Sentaurus TCAD For Device modelling, Sentaurus TCAD is used to implement both TFET and FinFET structures in device level.Sentaurus TCAD is a workbench which has a complete graphical arrangement for creating, executing, and visualizing the Simulations and various other Data [5].
In this paper, Both SDE and S-device is being used.In SDE (Synopsys Sentaurus-structure editor), the device is being modelled where the structure is built with different doping concentrations and different types of materials.After the device is built, it is meshed with certain number, which helps to study the device in a better way.According to the SDE, all the required parameters are considered to that of the SDE and with a set of instructions or coding the needed physics of the device and math, the wanted graphs are plotted and observed.Then the output or the results are analyzed to match with the better performance of the device.TFET has different switching mechanism than that of MOSFET.TFET works well for lower power devices.TFET works on the principle quantum-tunneling effect which is also known as Band to Band tunneling.TFET works by tunneling the source to drain barrier instead of diffusing over the barrier.Thus, there are two conditions for the Quantum-Tunneling to occur which is, the barrier should be thin over a larger area and there should enough density states on either side of the transmission and receiving ends to supply energy locations for those carriers [6].
TFET has MOSFET like structure but has reverse doping in both drain and source.In MOSFET, the diffusion happens over the barrier, whereas, in the TFET the tunneling happens through the barrier.There are two types of junctions based on the doping in P-I-N junction which are homojunction and heterojunction.
In Homojunction same kind of doping is between the contact that is silicon to silicon, whereas, in heterojunction p-typed is doped with Ge (Germanium) and n-type is doped with silicon (Si) and intrinsic type remains silicon.There are different modeling methods used in TFET which are Kane's Model and Atomistic quantum modeling [7].
When the source's valence\band and the channel's conduction\band overlap, the\tunnelling current in a TFET sub-threshold\slope abruptly changes.TFET\has higher control\over the gate for which it produces better performance and has improves characteristics over the MOSFET.On comparing the thin body size for the Single Gate and Double Gate, thin body is said to have lower subthreshold-swing and high drive.The effect of having a thin body does not show any visible change in the single and double gates [8]- [9].

Principle of Operation of TFET
The TFET follows quantum Tunnelling Effect in ultra-low power devices.Quantum Tunnelling or Band-to-Band Tunnelling, simply explains barrier penetration, which is an atom passing through potential energy barrier.The Probability of penetration of an atom decreases exponentially with barrier height and width and mass of the particle.The Potential energy barrier has high energy than that of the atoms or particle's kinetic energy.A particle has a probability of penetrating through the barrier if the barrier thickness is thin without sufficient energy [10].

Characteristics of TFET
TFET has less OFF-current as well as ON current and subthreshold slope compared to that of MOSFET.Thus, there is a cutting of supply voltage, which in turn increases the speed and performance of the device.
The Tunnel-FET is a P-I-N type junction, where both the drain and source are densely doped but the intrinsic layer is very sparsely doped [11].
The quantum-tunnelling propagation is expressed as - Tunnelling current can be expressed as: Sub-threshold-swing can be expressed as: Website: www.ijeer.forexjournal.co.inDesigning of Tunnel FET and FinFET using Sentaurus TCAD FinFET is a multi-gate MOSFET device with a channel which looks a FIN.A thin or slight silicon film is covered over the channel.There are two kinds of FinFETs formations such as SOI (Si on insulator) and Bulk.
Due to depletion of channel-length in MOSFET, there is an elevation in the short channel effects.These SCE (short-channel effects), depends on limiting the e-(electron) drift and changing the threshold voltage [12].
The FinFET is made up of substrate (made up of silicon material), Oxide layer, Channel (silicon material), Gate-Oxide (SiO2), source is made up of Silicon and drain as well is made up of silicon material.There are different types of FinFET such as double gate, tri-gate, Shorted gate and insulated or isolated gate FinFETS.FinFETS has better performance, operates at low voltage, less leakage currents and power.
In FinFET, the drain current escalates as bias is given drain terminal.FinFET has very less power consumption, better performance, and has a high operating speed.The main drawback of FinFET is that it very expensive to fabricate compared to Mos-FET.It is mostly used in microprocessors and other electronic components [3]. ) is significantly lower at 5.06E-15 S, implying that it may provide lower signal amplification compared to the FinFET.However, the TFET demonstrates a saturation current (  ) of 8.122e-7 A, which is higher than that of the FinFET.This suggests that the TFET can handle a greater current flow when fully activated.
In terms of resistance, the ON resistance (Ron) of the FinFET is 131.2Ohms, while the TFET exhibits a higher ON resistance of 272.6 Ohms.A lower ON resistance allows for better conduction and less power loss in the transistor.Additionally, the output resistance (Rout) of the FinFET is 2.9e+9 ohms, while the TFET's output resistance is significantly higher at 9.25e+16 ohms.A higher output resistance may result in reduced signal degradation at the output.The TFET device is modelled using P-I-N based model, where the P type is doped with Boron (Source), intrinsic channel is doped as a channel and N type is doped with Arsenic (Drain).
Masking is done for the device and high masking is done for the channel region.After masking the device the analysis is performed in Sentaurus device (S-device).Then analysis is performed on the device and I-V characteristics, electric Field and energy band diagram is extracted.

░ 5. CONCLUSIONS
The analysis of the TFET and FinFET models in Sentaurus TCAD provides insights into their respective characteristics.While the TFET offers a lower threshold voltage and higher saturation current, indicating potential energy efficiency benefits and current-handling capabilities, it may have limitations in terms of signal amplification and higher ON resistance.The FinFET, with a higher threshold voltage, exhibits superior signal amplification capabilities, lower ON resistance, and a moderate saturation current.The specific choice between the two transistors would depend on the application requirements and desired trade-offs between energy efficiency, signal amplification, and conduction properties.

░ 6. ACKNOWLEDGMENTS
Our thanks to the experts who have contributed towards development of the template.

Figure 7 . 3 . 1 ░ 4 .
Figure 7. Id vs Vgs ░ 3.1 Principle of Operation of FinFETThe working principle of FinFET is same to that of MOS transistor.A regular MOSFET has conducting channel on the surface whereas the FinFET has conducting channel on three sides.The MOSFET has less control over device as channel is decreased.The FinFET produces less leakage and has higher potential for larger increases in power[2] [4].