"Atomistic" Dopant Profiling Using Scanning Capacitance Microscopy

In this article we investigate the possibility to use scanning capacitance microscopy (SCM) for 3-D dopant profiling. It is shown that SCM with probes that have a radius under 10 nm, could be potentially used to determine the x-y-z coordinates of the doping atoms (or ionized impurities) in a layer of a thickness equal to the width of the depletion region. An inversion algorithm that computes the locations of the dopants from the experimental capacitance-voltage (C-V) measurements is presented for the first time. The algorithm is based on the evaluation of the doping sensitivity functions of the differential capacitance and uses a gradient-based iterative method to compute the locations of the dopants.