Transcript MOS Capacitor Picture

MOS Capacitor Picture
MOS Electrostatics
Condition is called flatband --- the voltage when this occurs
is called flatband
This state is the baseline operating case --- a capacitive
divider has one free parameter
MOS Electrostatics
Depletion Condition --- gate charge is terminated by charged
ions in the depletion region
Part of this region is often referred to as weak-inversion
MOS Electrostatics
Inversion --- further gate charge is terminated by carriers
at the silicon--silicon-dioxide interface
MOS Structure Electrostatics
MOS Electrostatics
MOS-Capacitor Regions
Surface potential
moving from
depletion to
inversion
Qs = e
(Y - Vs)/UT
Depletion (k(Vg - VT) - Vs < 0)
Qs = e
(k(Vg - VT) - Vs)/UT
Qs = ln( 1 + e
(k(Vg - VT) - Vs)/UT
)
Inversion (k(Vg - VT) - Vs > 0)
Qs = (k(Vg - VT) - Vs)/UT
MOS Capacitor Picture