A Pathway for Electron Beam Assisted Back-Contact Free Electrical Atomic Force Microscopy

Scanning probe microscopy (SPM) has become one of the promising and reliable metrology techniques for semiconductors and other bulk materials characterization due to its nanoscale characterization ability. However, electrical characterization using SPM e.g. conductive atomic force microscopy is often challenging and sometimes unsuitable for complex samples or particular locations within the sample because of the requirement of physical back-contact. In this work, we report the use of electron beam (e-beam) as a virtual back-contact that is completely free from any physical back-contact requirement and thus relevant sample preparation also does not require anymore. We demonstrate that SEM e-beam can directly deliver the charge carriers towards the sample without any physical contact while a conductive probe scans and collects the electrical information from the sample. We performed e-beam assisted C-AFM on metal, bulk and 2D materials without any conventional back-contact. Our result reveals that the e-beam based virtual back-contact can eliminate the need for conventional physical back-contact in electrical SPM while unlocking the opportunities for automated in-line metrology.