Characterization of a point-contact on silicon using force microscopy-supported resistance measurements
A conductive atomic force microscope (AFM) tip based on B-implanted diamond has been developed for the determination of the spatial distribution of charge carriers in semiconducting structures. The characteristics of this tip have been determined by studying the current-voltage behavior as a function of substrate resistivity and tip load. From this work a model of the electrical properties of the microcontact is emerging. It includes an Ohmic contribution to the overall resistance, which is related to the plastically deformed area, and contributions from a barrier. The tip imprints have been imaged with AFM and their physical dimensions are seen to match the requirements of the model. From resistance measurements on uniformly doped silicon a calibration curve has been established which can be used as a standard to convert measured resistance into resistivity.