Characterization of a point-contact on silicon using force microscopy-supported resistance measurements

Abstract

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.