How to calculate the capacitor of the MOSFET?

[gaom9]

Hi,
Can anyone tell me how to calculate the capacitors of the MOSFET, please?
Cgs, Cgd, Csb, Cdb.
How to get them by hand calculation, please?


Thank you.
Best regards!

 

[holddreams]

Allen's book, page 79 ~87.

 

[jecyhale]

I think you may simulate it. It will be close to the fact.

 

[jigisha]

hi...........

go for the book VLSI technology by SUNG MU KANG

in that refer chapter-3 in which the depth analysis is given on MOSFET. infact u'l find its entire derivation with explanation for capacitance like cgs,cgd etc....

go 4 it........

 

[gaom9]

Thank you, everyone.
I have read Allen's book, page 79 ~87.
But I still have some question:
1 About the area and perimeter of the source and drain
Can we also use the L1=L2=L3=2um in Allen's book, page 79 ~87 to calculate the area and perimeter of the source and drain.
2 About the CGBO of the model, I can not find the CGBO model in 0.18um CMOS model, CGBO is not a spice model of level 49, how can I handle it?


Thank you.
Best regards!

 

[malizevzek]

CGBO - you should find it in your process parameters. if not, you can calculate it using the well-known formula from PN junction, but you'll need values of doping concentrations

 

[gaom9]

Thank you, malizevzek
CGBO is not the parameter of the Level 49 model.
And I do not know the doping concentrations, too.

 

[layoutmaster]

I agree with malizevzek. THat data MUST be listed somewhere in your process specification..., very close to the place where you'll find the dopings if you want to calculate it manually...