Scanning Capacitance Microscopy (SCM) is used to characterize a sample surface by recording local changes in capacitance between the surface and a metal probe. The tip-sample capacitance can be probed by modulating carriers with a bias containing AC and DC components. An amplifier is used to measure the capacitance sensor output with a high signal-to-noise ratio. The magnitude of the SCM output (dC/dV) signal is a function of carrier density or dopant concentration.

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