Noncontact-mode scanning capacitance force microscopy towards quantitative two-dimensional carrier profiling on semiconductor devices

Scanning capacitance force microscopy (SCFM) is a promising tool for investigation of two-dimensional carrier density distribution on semiconducting devices. Its sensitivity is strongly dependent on the $Q$ factor of the mechanical resonance mode of the cantilever. Therefore, measurement in vacuum is more appropriate for increasing the sensitivity. In this letter, the authors describe noncontact-mode (NC) SCFM which is combined with the frequency modulation detection method and its signal characteristics. The authors derived a quasiquantitative calibration curve which correlates to the amplitude signal in NC-SCFM to the dopant density. Using the calibration curve, the authors obtained a quasiquantitative two-dimensional dopant density distribution map on a cross-sectional transistor device.