Metal-mediated exfoliation has been demonstrated as a promising approach for obtaining large-area flakes of two-dimensional (2D) materials to fabricate prototypical nanoelectronics. However, several processing challenges related to organic contamination at the interface of a 2D material and gate oxide must be overcome to realize robust devices with high yields. Here, we demonstrate an optimized process to realize high-performance field-effect transistor (FET) arrays from large-area (∼5000 μm2), monolayer MoS2 with a yield of 85%. A central element of this process is an exposed material forming gas anneal (EM-FGA) that results in uniform FET performance metrics (i.e., field-effect mobilities, threshold voltages, and contact performance). Complementary analytical measurements show that the EM-FGA process reduces deleterious channel doping effects by decreasing organic contamination while also reducing the prevalence of insulating molybdenum oxide, effectively improving the MoS2-gate oxide interface. The uniform FET performance metrics and high device yield achieved by applying the EM-FGA technique on large-area 2D material flakes will help advance the fabrication of complex 2D nanoelectronic devices and demonstrate the need for improved engineering of the 2D material-gate oxide interface.
Keywords: 2D material interfaces; 2D material processing; MoS2; field-effect transistor; forming gas annealing; nanoelectronics.