User:Wert21/sandbox

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Flat band voltage is effected by a few perameters in the device, but generally it is the difference in work functions between the metal and the bulk silicon. As the work function is related to energies in the band structures they can be described in terms of potential and so result in an offset voltage to compensate, i.e. so the zero (or low voltage condition) is actually a few tenths of a volt bigger than or less than 0V.

Flat band voltage in MOS capacitor is a voltage that must be applied to the gate to restore the flat-band condition

Flat band voltage is given by:

$$ V_{fb}=\Phi_{ms} - \frac {Q_{ox}}{C_{ox}}  $$

where &Phi;ms is a Work function difference: $$ \Phi_{ms}=\Phi_{m} - \Phi_{s} $$ and Qox is aeqvivalent oxide charge per unit area at the oxide-silicon interface.