Determination of the MOS oxide capacitance

A simple and explicit formula is derived to give the oxide capacitance from MOS C-V data in the accumulation but nondegenerate range of surface potential. The effect of majority impurity deionization is shown to be unimportant due to a higher surface concentration of majority carriers than impurities in the accumulation range. A first-order correction is obtained to take into account the degenerate or Fermi statistics of the majority-carrier surface concentration for oxide capacitance determinations from C-V data in the strong accumulation and degenerate range of surface potentials.