Theoretical problems of scanning capacitance microscopy

A theoretical description for scanning capacitance microscopy is presented. Solving the corresponding Laplace and Poisson equations, the potential and charge distributions induced by a rounded tip in a semiconductor sample were found and used to calculate the capacity. The results allow us to analyze the dependence of the measured capacity on the semiconductor doping level, applied voltage and tip geometry, and to estimate the spatial resolution of measurements and relate the measured capacity profile with the real doping profile in a sample.