lecture - mos & mosfet-1.ppt

7/18/2019 Lecture - MOS & MOSFET-1.ppt

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Field EffectField Effect

Transistors (1)Transistors (1)

Dr. Wojciech Jadwisienczak EE314


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Q: How we can do this?A: A new generation of MOSFETs for plastic electronics

http://www.plasticlogic.com
http://www.plasticlogic.com/http://www.plasticlogic.com/


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Chapter 12: FieldEffect ransistors

pp. !44"!##

1!onstr"ction of MOS#$MOS and %MOS&T'pes of MOSMOSFET asic Operation

*!haracteristics+S,all-Signal E."i/alent !irc"its0Ea,ples


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Figure 2 -120 nm footprint T-gate with

self-aligned source and drain contacts.

http://www.three-fives.com/latest_features/webzine_features/iainthainestory.html

Figure 4 showing the lateral etching control offered by digital recess

etching. !n both micrographs" the depth of the recess is #0 nm. The

micrograph on the left shows a wide gate recess with large lateral e$tentwhilst the micrograph on the right shows a recess tightly defined around the

gate footprint.


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"ilding A MOSFET Transistor 2sing Silicon

http:33,icro,agnetfs"ed"3electro,ag34a/a3transistor3indeht,l


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5t is done $ow6 how does itwor7?


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8FET and MOSFET Transistorsor8FET9 8"nction Field Effect TransistorMOSFET - Metal Oide Se,icond"ctor Field Effect Transistor

n-channel MOSFET p-channel MOSFET

;


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n-channel MOSFET asic Operation

Operation in the !"toff region

Sche,atic

pn 4"nction:forward@ias6 re/erse@ias

ihen /S


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Operation in the Triode egion

For /iSB/S-Ct=and /SDCt= the $MOS is operating in thetriode region

esistor li7e characteristic( @etween S 62sed as /oltage controlled )

For s,all /S6 iis proportional

to the ecess /oltage/S-Ct=


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Operation in the Sat"ration egion (/Sis increased)

Taperingof thechannel

iis s,allerwhen/S islarger

( )[ ]2

02 DSDStGSD vvVvKi

=2

KP

L

WK

=

e/ice para,eter % for

$MOSFET is *= A3C#( )2

0tGSD VvKi =

>hen /


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!haracteristic

2DSD Kvi =

Ea,ple 1#1

!hannel length,od"lation

iddepends on /Sinsat"ration region

(appro: i


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p-channel MOSFET asic Operation

5t is constr"cted @' interchanging the nandpregions ofn-channel MOSFET

S',@ol

!haracteristic

How does operatep-channel MOSFET?-/oltage polarities-ic"rrent-sche,atic


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;oad-;ine Anal'sis of $MOS A,plifier

5t is a graphical anal'sis si,ilar to load-line anal'sis of pn diode

Sche,atic

Anal'sisG

GGinGS Vtvtv += )()(

4)200sin()( += ttvGS

)()( tvtiRV DSDDDD +=

)()(20 tvtiRDSDD

+=

5np"tloop

O"tp"tloop

;oadline

/S /S

>e loo7 for operatingpoint


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;oad-;ine Anal'sis of $MOS A,plifier

;oad line )()(20 tvtiRDSDD

+= Ta7ing i


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5np"t signal )200sin(1)( ttvin =

;oad-;ine Anal'sis of $MOS A,plifier(pea7-to-pea7 a,plit"de is #C)

1#C

5n/erseoperation

The positi/e pea7 of the inp"t occ"rs at the sa,e ti,e as the ,in

/al"e of /S These are not s',,etrical sin"soidsI (nonlinear distortion)


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ias !irc"itsAnal'sis of a,plifier circ"its is often "nderta7en in two steps:(1) The dc circ"it anal'sis to deter,ine the Q point 5t in/ol/es the

nonlinear e."ation or the load-line ,ethod This is called @iasanal'sis(#) 2se a linear s,all-signal e."i/alent circ"it to deter,ine circ"it

para,eters

The fied-pl"sself-@ias circ"it

5np"t O"tp"t

E."i/alentcirc"it

21

2

RR

RVVDDG

+

=

DSGSG iRvV +=

Anal'sisG

Ass",e the C


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ias !irc"its

%lot ofDSGSG

iRvV += ( )2

0tGSD VvKi =and

isregarded root

for /SBCt=

2se onl' largerroot for /Sands,aller for i

Ea,ple 1##

lecture - mos & mosfet-1.ppt

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