(Received August 15, 1972)
The MIS conductance method is important for estimating the interface state density in the Metal-Insulator-Semiconductor structure. There are at present two models for the density distribution. One is Goetzberger's model based on random distributions (with variance σ2) of the interface charges along the interface, the other is Preier's model for the trap distributions (with attenuation constant α) along the depth in the insulator near the interface. However, it is found that either of the above parameters which should be constant varies with the measuring frequency. Therefore a new two-dimensional parameter model is proposed which gives good agreement with experiments. Each of the above models is found to be a special case with very large α or 0.6 for σ of the proposed model.