Scanning Capacitance Microscopy Mode (SCM)

Scanning Capacitance Microscopy (SCM) is a secondary imaging mode derived from contact AFM that maps variations in majority electrical carrier concentration (electrons or holes) across the sample surface (typically a doped semiconductor).

An AC bias voltage is applied between the tip and sample. The tip scans across the sample surface, and changes in capacitance between the tip and the sample surface are monitored by an extremely sensitive high-frequency resonant circuit.

SCM is commonly used for two-dimensional profiling of dopants in semiconductor process evaluation and failure analysis.