Scanning capacitance microscopy (SCM) is currently one of the most promising tools for twodimensional carrier profiling. This technique, based upon atomic force microscope (AFM) operated in the contact mode, uses a conductive probe which is scanned over the semiconductor surface. The conductive probe, oxide on the surface of the semiconductor, and the semiconductor substrate form a metal-oxide-semiconductor (MOS) structure. An a.c. bias is applied to the tip and the capacitance of the MOS structure is monitored. The a.c. bias changes the depletion of carriers in the semiconductor and thus the total capacitance of the structure. The maximum capacitance of the MOS structure is obtained when the semiconductor is in accumulation and the total capacitance of the structure is the capacitance of the semiconductor surface oxide. The minimum capacitance is obtained when the semiconductor region under the tip is in inversion. Since SCM the output signal is proportional to the differential capacitance, to get a high signal we need to maximize the difference between the maximum and minimum in the total MOS capacitance.