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SIMULATION STUDY ON REDUCTION OF DRAIN CURRENT IN

MOSFET

PROJECT GUIDE GROUP MEMBERS Dr.B.GOPI,B.E.M.E.Ph.D P.MENAKA G.NIVEDHA M.PAVITHRA M.POORNIMA G.PRIYA

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A numerical study on performance of MOSFET is analyzed. The drain current value of MOSFET can be reduced by varying substrate, gate and gate oxide materials. By reducing the drain current (Id), the power dissipation can be reduced. Thus the performance of the device can be increased by reducing the drain current (Id).

ABSTRACT

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Single gate MOSFETOutput characteristicsTransfer characteristicsOn state ResistancePower dissipation

WORK DONE

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SINGLE GATE STRUCTURE

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SUBSTRATE MATERIALS Silicon GermaniumGATE MATERIAL AluminiumGATE OXIDE MATERIALS Silicon di oxide Hafnium oxide Air

MATERIALS

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Id=knW/L((Vgs-VT)Vds-(Vds2/2))

kn=Coxµn

WhereId – drain current

kn - process parameter

W-width of gateL-length of gateVgs – gate source voltage

VT - threshold voltage

Vds - drain source voltage

Cox - gate oxide capacitance

µn - charge carrier effective mobility

DRAIN CURRENT EQUATION

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Output characteristics is a plot between drain voltage(VDS ) and drain current(ID) by keeping gate voltage(VGS) constant.

CUTOFF REGION: ID =0 LINEAR REGION: ID= µnC0xW/L ((VGS-VT)VDS-(VDS

2/2))

OUTPUT CHARACTERISTICS

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SATURATION REGION:ID=0.5 µnC0xW/L(VGS-VT)2

µn – mobility

C0X – capacitance of oxide layer

C0X – (ε0 εr)/t0x

ε0 –permittivity of free space

ε0 –8.854*10^-12

εr –relative permittivity

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OUTPUT CHARACTERISTICS OF MOSFET WITH Al AS GATE MATERIAL , SiO2 AS OXIDE LAYER AND Si AS SUBSTRATE

Vds(2V) ID(A) Vds (3V) ID(A) Vds (4V) ID(A) Vds (5V) ID(A) Vds (6V) ID(A)

0 5.01E-17 0 5.61E-17 0 6.21E-17 0 1.09E-16 0 8.17E-17

0.2 0.000273 0.2 0.000425 0.2 0.000544 0.2 0.000642 0.2 0.000725

0.4 0.000462 0.4 0.000778 0.4 0.001026 0.4 0.00123 0.4 0.001403

0.6 0.000554 0.6 0.001029 0.6 0.001414 0.6 0.001733 0.6 0.002004

0.8 0.000583 0.8 0.001172 0.8 0.001689 0.8 0.002129 0.8 0.002506

1.0 0.000595 1 0.001232 1 0.001853 1 0.002407 1 0.002893

1.2 0.000604 1.2 0.001255 1.2 0.00193 1.2 0.002575 1.2 0.003161

1.4 0.000612 1.4 0.001268 1.4 0.001963 1.4 0.00266 1.4 0.003324

1.6 0.000618 1.6 0.001279 1.6 0.00198 1.6 0.002698 1.6 0.00341

1.8 0.000624 1.8 0.001288 1.8 0.001993 1.8 0.002719 1.8 0.003451

2 0.00063 2 0.001296 2 0.002004 2 0.002733 2 0.003474

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Output Characteristics of MOSFET with Silicon as substrate and SiO2 ,HfO2, Air as oxide materials

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RON = 1/(μn COX W/L)(Vgs-Vds-VT)

μn-charge carrier effective mobility

COX -gate oxide capacitance

W –width of the gateL-length of the gateVgs – gate source voltage

VT - threshold voltage

Vds - drain source voltage

ON STATE RESISTANCE

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ON RESISTANCE OF MOSFET WITH Al AS GATE MATERIAL , SiO2

AS OXIDE LAYER AND Si AS SUBSTRATE

Id(A) RON2(Ω) Id(A) RON3(Ω) Id(A) RON4(Ω) Id(A) RON5(Ω) Id(A) RON6(Ω)

5.01E-17 0 5.61E-17 0 6.21E-17 0 1.09E-16 0 8.17E-17 00.000273 733.8

0.000425 470.63 0.000544 367.715 0.000642 311.554 0.000725 275.6860.000462 865.636

0.000778 514.099 0.001026 389.966 0.00123 325.317 0.001403 285.1680.000554 1082.27

0.001029 582.824 0.001414 424.28 0.001733 346.182 0.002004 299.3530.000583 1371.47

0.001172 682.501 0.001689 473.524 0.002129 375.728 0.002506 319.1840.000595 1679.4

0.001232 811.741 0.001853 539.671 0.002407 415.446 0.002893 345.6740.000604 1986.01

0.001255 956.32 0.00193 621.607 0.002575 466.016 0.003161 379.6120.000612 2288.94

0.001268 1103.77 0.001963 713.289 0.00266 526.361 0.003324 421.1170.000618 2587.96

0.001279 1250.96 0.00198 807.93 0.002698 593.056 0.00341 469.2050.000624 2883.39

0.001288 1397.34 0.001993 902.962 0.002719 662.115 0.003451 521.612.00063 3175.55

0.001296 1542.81 0.002004 997.82 0.002733 731.676 0.003474 575.788

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On state resistance of MOSFET with Silicon as substrate and SiO2,HfO2,Air

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PD= ID2RON

ID = drain current

RON = ON state resistance

POWER DISSIPATION

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POWER DISSIPATION OF MOSFET WITH Al AS GATE MATERIAL , SiO2 AS OXIDE LAYER AND Si AS SUBSTRATE

Id(A) Pd2(W) Id(A) Pd3(W) Id(A) Pd4(W) Id(A) Pd5(W) Id(A) Pd6(W)

5.01E-17 0 5.61E-17 0 6.21E-17 0 1.09E-16 0 8.17E-17 0

0.000273 5.45E-05 0.000425 8.50E-05 0.000544 0.000109 0.000642 0.000128 0.000725 0.000145

0.000462 0.000185 0.000778 0.000311 0.001026 0.00041 0.00123 0.000492 0.001403 0.000561

0.000554 0.000333 0.001029 0.000618 0.001414 0.000848 0.001733 0.00104 0.002004 0.001203

0.000583 0.000467 0.001172 0.000938 0.001689 0.001352 0.002129 0.001703 0.002506 0.002005

0.000595 0.000595 0.001232 0.001232 0.001853 0.001853 0.002407 0.002407 0.002893 0.002893

0.000604 0.000725 0.001255 0.001506 0.00193 0.002317 0.002575 0.00309 0.003161 0.003793

0.000612 0.000856 0.001268 0.001776 0.001963 0.002748 0.00266 0.003724 0.003324 0.004654

0.000618 0.000989 0.001279 0.002046 0.00198 0.003169 0.002698 0.004317 0.00341 0.005456

0.000624 0.001124 0.001288 0.002319 0.001993 0.003588 0.002719 0.004893 0.003451 0.006212

0.00063 0.00126 0.001296 0.002593 0.002004 0.004009 0.002733 0.005467 0.003474 0.006947

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Power Dissipation of MOSFET with Silicon as substrate and SiO2,HfO2,Air

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Output characteristics is a plot between gate voltage (VGS ) and drain current(ID) by keeping drain voltage(VDS) constant

TRANSFER CHARACTERISTICS

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TRANSFER CHARACTERISTICSOF MOSFET WITH Al AS GATE MATERIAL , SiO2 AS OXIDE LAYER AND Si AS SUBSTRATE

Gate voltage(V) Drain current (A)

0 1.44E-11

0.2 6.74E-11

0.4 5.83E-09

0.6 7.36E-07

0.8 2.09E-05

1 8.30E-05

1.2 0.000171

1.4 0.000274

1.6 0.000386

1.8 0.000506

2 0.00063

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Transfer Characteristics of MOSFET with Silicon as substrate and SiO2,HfO2 ,Air

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“HYBRID Ge-Si BASED MOSFET DEVICES” in the “International Journal of Electrical, Electronics and Computer System (IJEECS)”

“VARIATION OF GATE MATERIALS FOR HYBRID GE-SI MOSFET” in the “International Journal of Nanotechnology and Application journal”

PAPER PUBLISHED

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“HYBRID AlGaAs-SI BASED MOSFET DEVICES” in the “IOSR Journal of vlsi and signal processing”

“TRI-GATE STRUCTURE TO REDUCE DRAIN CURRENT” in “International Journal Of Electrical, Electronics and Telecommunication Engineering Recent Science Publications”

ACCEPTED FOR PUBLICATION

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“ANALYSING THE PERFORMANCE OF MOSFET BY VARYING THE SUBSTRATE MATERIALS” in “Innovative Research in Electrical, Electronics, Instrumentation and Control Engineering (IJIREEICE)”

“COMPARATIVE STUDY ON THE PERFORMANCE OF MOSFET WITH GOLD AND SILVER AS GATE MATERIALS” in “IMPACT :International Journal of Research in Engineering & Technology”

ACCEPTED FOR PUBLICATION

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We have obtained output characteristics, transfer characteristics, ON resistance, power dissipation for MOSFET by changing the substrate and gate materials.

Thus the power dissipation of MOSFET is reduced with the help of reducing the drain current and the performance of the device is increased through this.

CONCLUSION

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H. Iwai, Extended Abstracts 2008 8th International Workshop on Junction Technology (IWJT '08) (Shanghai, China 2008 May 15-16, IEEE Press) p. 1. [DOI:10.1109/IWJT.2008.4540004].

International Technology Roadmap for Semiconductors (ITRS) 2007

Edition. Available from: http://www.itrs.net/links/2007ITRS/Home2007.html. B. Razavi, Design of Analog CMOSIntegrated Circuits (McGraw-

Hill, Boston,MA, 2001).

R. F. Pierret, Semiconductor Device Fundamentals (Addison-Wesley, Reading,MA, 1996) p. 691.

REFERENCE

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J. Appenzeller et al., “Scheme for the fabrication of ultrashort channel MOSFETs,” Appl. Phys. Lett., vol. 77, pp. 298–300, July 2000

B. Yu et al., “15 nm gate length planar CMOS transistor,” in IEDM Tech.Dig., 2001, pp. 937–939.