Quality Control of Graphene Field-Effect Transistor Arrays Using Slit-Scanning Raman Microscopy

Large-scale graphene films enable the integration of graphene field-effect transistor (GFET) arrays onto chips. However, the transfer characteristics display variability across the array. This significant statistical variation in graphene quality combined with the lack of standardized protocols poses a major challenge to commercialization. In this study, we present a rapid, extensive, and high-resolution inspection technique using slit-scanning Raman microscopy. Raman imaging of all GFETs in the arrays was performed before conducting electrical measurements. The G-band and 2D-band peak positions were used to determine the hole carrier density (n_H) in the GFETs. Variations in n_H values across the arrays correlated with the V_DP values, which is a critical parameter of FET performance, validating this approach as an inspection method. Moreover, Raman peaks were tracked across 100 GFETs at different processing stages, revealing that spatial variations originated during the wet-transfer process. This method is vital for the scalable manufacturing of graphene devices.