In this work, the physical processes leading to contrast in scanning capacitance microscopy
SCM are investigated both experimentally and theoretically. Using a p-type epitaxial doping
staircase on silicon, we show that a monotonic dependence of the SCM signal on the doping
level is only obtained, if the tip bias is adjusted in a way that the sample is either in
accumulation or depletion. In the transition region, the SCM signal is nonmonotonic as a
function of doping and depends on the bias. Therefore, any doping concentration can yield a …