calculation of gate oxide capacitance

[kanna]

Can we calculate the gate oxide capacitance of a mosfet with the tutorial given in
http://quantumwise.com/publications/tutorials/item/511-calculation-of-atomic-scale-capacitance ?

[Anders Blom]

Not really. For a moscap you rather need to set up a device structure and look at the charge transfer under finite bias.

[kanna]

Hi,
I want to calculate gate-source capacitance for a given gate bias. I understand the part about setting up a device structure, but how do I get the charge transfer ?

Thanks
kanna

[Anders Blom]

I suppose you are mainly looking at how the electron density changes with bias, so you can just subtract the zero-bias electron density and that's your bias-induced charge transfer.