High-resolution and high-sensitivity detection of free carriers in semiconductors is critical due to the trend of device miniaturization and diversification. To address this need, the AFM-based techniques of scanning spreading resistance microscopy, scanning capacitance microscopy, scanning nonlinear dielectric microscopy (SNDM), scanning microwave impedance microscopy, and scanning microwave microscopy are used. This paper demonstrates enhanced SNDM with stepwise dC/dV and dC/dz imaging, qualitative analysis, quantitative analysis, and artifact-free carrier-density profiling of semiconductor devices. The trace mode in enhanced SNDM is switched between contact (dC/dV measurement) state and non-contact (dC/dz measurement) state for every line scan whereby the sampling intelligent scan mode is switched these states every pixel. Using IMEC Si standards and Si power MOSFET as examples demonstrates that this SNDM methodology can provide qualitative, quantitative, and artifact-free carrier density profiling of semiconductor devices.

Scanning nonlinear dielectric microscopy (SNDM) has improved significantly, achieving low-concentrated observations. Therefore, it is of great interest to observe how adsorbed water and other measurement environments influence SNDM measurements so that the material's dielectric properties can be detected. This study investigates how specific measurement environments, namely air, dry nitrogen, and vacuum environments, influence the SNDM and C-V curve measurements of semiconductor samples. The p-n structure created by ion implantation was measured by applied-DC-voltage SNDM, and in these environments, the corresponding C-V curves were obtained. As with the p-n structure sample, an abnormal result was obtained when a positive DC voltage was applied to an epi-Si sample in air. A low concentration level was clearly measured in vacuum. From these results, it can be concluded that measurement in a high vacuum is an effective way to obtain highly precise carrier distributions.