Measurement of semiconductor surface potential using the scanning electron microscope

摘要: We calibrate the secondary electron signal from a standard scanning microscope to voltage, yielding an image of surface or near-surface potential. Data on both atomically abrupt heterojunction GaInP/GaAs and diffused homojunction Si solar cell devices clearly show expected variation in potential with position applied bias, giving depletion widths locating metallurgical junctions accuracy better than 10 nm. In some images, distortion near p-n junction is observed, seemingly consistent effects lateral electric fields (patch fields). Reducing tube bias removes this distortion. This approach results rapid straightforward collection data using microscope.