[SOLVED] Capacitors between source, drain, gate and bulk

[fateme m]

I understand Cgb, we have a plate which is the gate poly and we have the oxide which acts as the dielectric and we have the channel as the second plate; they form the capacitor Cgb (or it's better to say C gate-channel, because poly and the CHANNEL have opposite charges on them not the BULK and the poly).

But I don't understand the Csb or Cdb, source and the drain are the first plates and the bulk acts as the second plate, what acts as the insulator or dielectric between these two plates??

someone said each two conductors make a capacitor, how is that?? I mean what about the insulator??

 

[fateme m]

I got it, the depletion region that is formed around the drain and source act as the insulator. Am I right?
which means we have a diode and also a capacitor around diffusion parts and the bulk...

 

[timof]

Yes, right - any diode or p-n junction has a depletion region between n- and p-doped regions, which acts as a capacitor.