Determination of the parameters of metal–insulator–semiconductor structures with ultrathin insulating layer from high-frequency capacitance–voltage measurements

A simple numerical method for processing the data of the high-frequency capacitance–voltage characteristics of metal–insulator–semiconductor structures is proposed. The approach is based on analyzing the experimental characteristics near the flat-band states, where the charge exchange of surface localized electron states is of little importance compared with changes in the near-boundary charged layer in the semiconductor. The developed technique makes it possible, first, to find the necessary parameters of the semiconductor and insulating layer and, second, to obtain the experimental field dependences of the energy-band bending in the semiconductor and the total concentration of the built-in charge, the charge of boundary states and minority charge carriers at the semiconductor–insulator interface in the range from the flat bands to deep depletion. The technique is well applicable to structures with an ultra-thin insulating layer. On $n$-Si-based metal–oxide–semiconductor samples with an oxide thickness of 39 $\mathring{\mathrm{A}}$, experimental approbation of the proposed approach is carried out. The accuracy of the obtained results is 2–3%.