FinFET Technology

Since the fabrication of MOSFET, the minimum channel length has been shrinking continuously. The motivation behind this decrease has been an increasing interest in high-speed devices and in very large-scale integrated circuits. The sustained scaling of conventional bulk device requires innovations to circumvent the barriers of fundamental physics constraining the conventional MOSFET device structure. The limits most often cited are control of the density and location of dopants providing high I on /I off ratio and finite sub threshold slope and quantum-mechanical tunneling of carriers through thin gate from drain to source and from drain to body.

The channel depletion width must scale with the channel length to contain the off-state leakage I off. This leads to high doping concentration, which degrade the carrier mobility and causes junction edge leakage due to tunneling. Furthermore, the dopant profile control, in terms of depth and steepness, becomes much more difficult. The gate oxide thickness tox must also scale with the channel length to maintain gate control, proper threshold voltage VT and performance. The thinning of the gate dielectric results in gate tunneling leakage, degrading the circuit performance, power and noise margin.

Alternative device structures based on silicon-on-insulator (SOI) technology have emerged as an effective means of extending MOS scaling beyond bulk limits for mainstream high-performance or low-power applications .Partially depleted (PD) SOIwas the first SOI technology introduced for high-performance microprocessor applications. The ultra-thin-body fully depleted (FD) SOI and the non-planar FinFET device structures promise to be the potential "future" technology/device choices. In these device structures, the short-channel effect is controlled by geometry, and the thin Si film limits the off-state leakage. For effective suppression of the off-state leakage, the thickness of the Si film must be less than one quarter of the channel length. The desired VT is achieved by manipulating the gate work function, such as the use of midgap material or poly-SiGe. Concurrently, material enhancements, such as the use of a) high-k gate material and b) strained Si channel for mobility and current drive improvement, have been actively pursued. As scaling approaches multiple physical limits and as new device structures and materials are introduced, unique and new circuit design issues continue to be presented. In this article, we review the design challenges of these emerging technologies with particular emphasis on the implications and impacts of individual device scaling elements and unique device structures on the circuit design. We focus on the planar device structures, from continuous scaling of PD SOI to FD SOI, and new materials such as strained-Si channel and high-k gate dielectric.

Partially Depleted [PD] SOI
The PD floating-body MOSFET was the first SOI transistor generically adopted for high-performance applications, primarily due to device and processing similarities to bulk CMOS device.
The PD SOI device is largely identical to the bulk device, except for the addition of a buried oxide ("BOX") layer. The active Si film thickness is larger than the channel depletion width, thus leaving a quasi-neutral "floating" body region underneath the channel. The V T of the device is completely decoupled from the Si film thickness, and the doping profiles can be tailored for any desired VT. The device offers several advantages for performance/ power improvement:

1) Reduced junction capacitance,

2) Lower average threshold due to positive V BS during switching.

3) Dynamic loading effects, in which the load device tends to be in high VT state during switching The performance comes at the cost of some design complexity resulting from the floating body of the device, such as

1) Parasitic bipolar effect and

2) Hysteretic VT variation.
Seminar on finFET technology







Since the fabrication of MOSFET, the minimum channel length has been shrinking continuously.

The motivation behind this decrease is seen in high speed devices and in very large scale integrated circuits.

The limits most often cited are:-

control of the density.

finite subthreshold slope .

quantum-mechanical tunneling .

The channel depletion width must scale with the channel length to contain the off-state leakage I off
this leads:-

high doping concentration.

The gate oxide thickness tox must also scale with the channel length to maintain :-

gate control.

proper threshold voltage VT .

The thinning of the gate dielectric results in :-

gate tunneling leakage.

degrading the circuit performance.

power and noise margin.

Partially depleted(PD)SOI was the first SOI technology introduced for high performance microprocessor applications.

  The PD SOI device is largely identical to the bulk device, except for the addition of a buried oxide (“BOX”) layer
The device offers several advantages for performance/ power improvement:-

reduced junction capacitance.

Parasitic bipolar effect.

Hysteretic VT variation.

Dynamic loading effects.

Gate Oxide Tunneling Leakage

Self heating

Soft Error Rate

Strained-Si channel And High-k Gate

Features of finFET:
Finfet consists of a vertical Si fin controlled by self_aligned double gate.

Main Features of Finfet are:-

Ultra thin Si fin for suppression of short channel effects

Raised source/drain to reduce parasitic resistance and improve currrent drive

Symmetric gates yield great performance,but can built asymmetric gates that target VT .

Finfets are designed to use multiple fins to achieve larger channel widths.

Source/Drain pads connect the fins in parallel.

As the number of fins is increased ,the current through the device increases.

.For eg: A 5 fin device 5 times more current than single fin device.

FinFET-DGCMOS Process Flow in Detail:
A conventional SOI wafer can be used as starting material for:-

Sacrificial oxidations.

Masked ion implantations.

specialized passive elements.

Gate deposition and etch.

DG devices like Fin FETs offer unique opportunities for microprocessor design.compared to a planar process in the same technology node,

FinFETs have reduced channel and gate leakage currents. This can lead to considerable power reductions when converting a planar design to fin FET technology.

Utilizing fin FETs would lead to a reduction in total power by a factor of two, without compromising performance.

Another possibility to save power arises when both gates can be controlled separately.

The second gate can be used to control the threshold voltage of the device, thereby allowing fast switching on one side and reduced leakage currents when circuits are idle.

Finally, separate access to both gates could also be used to design simplified logic gates.

This would also reduce power, and save chip area, leading to smaller, more cost-efficient designs. However chip designs using finFETs must cope with quantization of device width.

since every single transistor consists of an integral number of fins,each fin having the same height.

This article will present the simulation methodology of a self-aligned double-gate MOSFET structure (FinFET) using SILVACO 3-D simulation suite.

Device Features:-

A transistor is formed in a vertical ultra –thin Si fin and is controlled by a double-gate, which considerably reduced short channel effects.

the two gates are self aligned and are aligned to S/D.

S/D is raised to reduce the access resistance.

Up to date gate process: low temperature, high -k dielectrics can be used .

Device Simulation:
The 3-D SILVACO simulation suite including Device3D, DevEdit3D and TonyPlot3D, allows device engineers to study deep sub-micron devices which are 3-D by nature like the FinFET presented above.

A 3-D FinFET structure was designed by using DevEdit3D. This is an advanced tool for structure editing and mesh generation.


Simulations show that this structure should be scalable down to 10 nm.

This structure was fabricated by forming the S\D before the gate.

Further performance improvement is possible by using a thinner gate dielectric and thinner spacers.

FinFET is similar to the conventional MOSFET with regard to layout and fabrication.

. It is an attractive successor to the single gate MOSFET by virtue of its superior electrostatic properties and comparative ease of manufacturability.

Industrial research groups such as Intel, IBM and AMD have shown interests in developing similar devices, as well as mechanisms to migrate mask layouts from Bulk-MOS to FinFETs.

Design Issues such as high quality ultra thin fin lithography and source\drain resistance need to be resolved and a high-yield process flow needs to be established by process researchers before FinFETs can be used in commercial.

S. Thompson, P. Packan and M. Bohr, “MOS scaling , Transistor challenges for the 21st century,” Intel Tech.J.,vol.Q3 pp1-19,1998.

C.H.Wann, H. Noda, T. Tanaka, M.Yoshida and C. Hu, “A comparative study of advanced MOSFET concepts ,” IEEE Trans. Electron Devices, vol. 43, no. 10, pp 1742-1753, Oct. 1996

X. Huang, W.C. Lee, C.Kuo, D.Hisamoto, L. Chang, J. Keidzerski, E. Anderson, H.Takeuchi, Y.K. Choi, K.Asano.



Important Note..!

If you are not satisfied with above reply ,..Please


So that we will collect data for you and will made reply to the request....OR try below "QUICK REPLY" box to add a reply to this page
Popular Searches: epitaxial finfet, finfet simulation steps doc, pdf seminar report on finfet technology, finfet basic operation, finfet, pdf on literature review of finfet, abstract of finfet technology,

Quick Reply
Type your reply to this message here.

Image Verification
Please enter the text contained within the image into the text box below it. This process is used to prevent automated spam bots.
Image Verification
(case insensitive)

Possibly Related Threads...
Thread Author Replies Views Last Post
  Flying Windmills or Flying Electric Generator (FEG) technology project report helper 9 23,944 02-10-2018, 03:32 PM
Last Post: Guest
Last Post: [email protected]
  Advancements In Inverter Technology For Industrial Applications project report tiger 18 24,282 17-04-2017, 12:30 PM
Last Post: jaseela123d
  Cellonics Technology computer science crazy 2 3,857 07-03-2016, 11:39 AM
Last Post: seminar report asees
  Wavelet Video Processing Technology computer science crazy 8 8,096 05-03-2015, 02:30 PM
Last Post: Guest
  Circuit Breaker Maintenance by Mobile Agent Software Technology project topics 16 13,996 23-04-2014, 08:27 PM
Last Post: Guest
  Thermal infrared imaging technology seenas 3 1,927 30-09-2013, 11:28 AM
Last Post: computer topic
  GEOTHERMAL POWER GENERATING TECHNOLOGY project topics 11 9,496 25-06-2013, 10:00 AM
Last Post: computer topic
  Magnetohydrodynamic power generation technology (MHD ) computer science crazy 13 22,802 20-06-2013, 05:51 PM
Last Post: Guest
  SMARTGRID TECHNOLOGY seminar class 7 6,696 06-02-2013, 09:58 AM
Last Post: seminar details

Forum Jump: