Electron‐Beam Excited Conductive Atomic Force Microscopy for Back Contact Free, Wafer‐Scale and In‐Line Compatible Electrical Characterization of 2D Materials

Electrical atomic force microscopies (AFMs) have emerged as leading metrology techniques for evaluating the quality of 2D materials. Their advantages include high-resolution electrical mapping, non-destructive measurement, and the ability to probe nanoscale defects and transport properties. Conductive AFM (C-AFM) has been particularly instrumental, enabling the direct observation of individual vacancies and vacancy clusters, voids, wrinkles, and cracks. Despite this incredible versatility, C-AFM remains a two-probes method, thus it is limited by the need for physical back-contact. Creating this back contact is complex and time-consuming. More importantly, this requirement prevents C-AFM from being a viable in-line metrology technique. Here, it is demonstrated that a low-energy e-beam impinging on the sample surface can be used to perform C-AFM, in a new configuration that is electron-beam (e-beam) excited conductive atomic force microscopy (EBC-AFM). This approach enables comparable results to classic C-AFM sensitivity, while unlocking applications that were not previously possible. After introducing the experimental setup, the main parameters associated with the e-beam and their impact on the C-AFM measurement are studied. Finally, using several 2D materials as testbeds, the competitive electrical mapping capabilities of EBC-AFM for defect assessment are demonstrated. Furthermore, this technique overcomes limitations for studying isolated flakes and enables wafer-scale characterization of 2D materials.