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Capacitance between nwell to substrate??

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hebu

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Does the device model include the cap between nwell to sub?
If it dosen't, how to estimate the capacitance by rule of thumb?

Thanks,
 

Area junction capacitance NWELL/PSUB = 0.086 fF/um² for 0.6 um CMOS technology, which I use.
You may use diode NWELL/PSUB for simulation of this capacitance.
 

If you are using RF CMOS model then it should be included for you. Just check the report provided by the foundry.
 

You can find it as below in Parameter Library,

* Junction Cap Param *
.
.
CJ=0.001
MJ=0.300
PB=0.600
CJSW=6.0E-11
MJSW=6.0E-16
.
.

if you use MOSFETs,
CBD=Cj*(Bottom-Area)/(1-VBD/PB)^Mj + Cjsw*(Side-Round)/(1-VBD/PB)^Mjsw
CBS=Cj*(Bottom-Area)/(1-VBD/PB)^Mj + Cjsw*(Side-Round)/(1-VBD/PB)^Mjsw

* VBD = V(bulk-drain), VBS = V(bulk-source)

and if you use well,
CBB=Cj*(Bottom-Area) + Cjsw*(Side-Round)

Notify some units for handy calculation.
 

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