The Designer's Guide Community Forum

The Designer's Guide Community Forum
https://designers-guide.org/forum/YaBB.pl
Modeling >> Semiconductor Devices >> For MOS Cap, is the a depletion region in MOS when VFB < VGB < 0?
https://designers-guide.org/forum/YaBB.pl?num=1495759649

Message started by mpig09 on May 25^th, 2017, 5:47pm

Title: For MOS Cap, is the a depletion region in MOS when VFB < VGB < 0?
Post by mpig09 on May 25^th, 2017, 5:47pm

Hi all:

Many books explain the MOS Cap value is Cox(oxide cap) serial Cdep(depletion cap) when VFB < VGB < VTH,
I have a questions: is there a depletion region in MOS when VFB < VGB < 0?

VFB : Flat band voltage

If Yes, could you help me to understand it.

Thank.

mpig

Title: Re: For MOS Cap, is the a depletion region in MOS when VFB < VGB < 0?
Post by Maks on May 27^th, 2017, 1:58pm

There is always depletion region when Vg > VFB.
At Vg> Vt though, the depletion regions is "screened" (or shielded) by the inversion layer (a thin layer of electrons in the channel, at the Si/oxide interface, supplied from N+ source/drain regions).

If you want to understand what all these terms mean - depletion, deep depletion, accumulation, inversion - you can read any textbook on semiconductor device physics (for example, S.Sze book "Physics of semiconductor devices").

Max

Title: Re: For MOS Cap, is the a depletion region in MOS when VFB < VGB < 0?
Post by mpig09 on Jun 5^th, 2017, 2:49am

Hi Max:

I have solved the problem.
:)

mpig