This paper reports the two-dimensional (2-D) carrier/dopant profiling technique by Kelvin-probe force microscopy (KFM). Before surface potential was measured, a feedback control circuit was used to improve signal response speed. The effect of surface treatment on the contrast in surface potential images was studied. Then the correlation between surface potential difference measured by KFM and surface carrier/dopant concentration obtained by spreading resistance profiling, the capacitance-voltage method, and secondary ion mass spectroscopy analysis was established. On the basis of these results, the carrier depth profiling of a p-n junction and the detection of a p-n junction array with small pitch have been successfully demonstrated.
- Kelvin-probe force microscopy
- Scanning probe microscopy
- Surface potential