Fluctuation model of the capacitance-voltage characteristic of MDS structure

Abstract

The capacitance-voltage (C-V) characteristic of a metal-dielectric-semiconductor (MDS) structure has been theoretically studied with allowance for statistical fluctuations of a built-in charge in the dielectric. The influence of charge fluctuations on the energy spectrum of the density of surface states and other parameters of MDS structures is considered. It is shown that, in the case of using the conventional capacitive methods of determination of the density of surface states, the presence of charge fluctuations can lead to both overstated (in the regimes of enrichment and inversion) and understated (in the case of depletion) values. In the latter case, the error can be manifested by a negative density of states. Allowance for the built-in charge fluctuations is also necessary for increasing the accuracy of determination of some other MDS structure parameters by the capacitive techniques.