200-mm-wafer-scale integration of polycrystalline molybdenum disulfide transistors

Abstract

Two-dimensional semiconductors are an attractive material for making thin-film transistors due to their scalability, transferability, atomic thickness and relatively high carrier mobility. There is, however, a gap in performance between single-device demonstrations, which typically use single-crystalline two-dimensional films, and devices that can be integrated on a large scale using industrial methods. Here we report the 200-mm-wafer-scale integration of polycrystalline molybdenum disulfide (MoS2) field-effect transistors. Our processes are compatible with industry, with processing performed in a commercial 200 mm fabrication facility with a yield of over 99.9%. We find that the metal-semiconductor junction in polycrystalline MoS2 is fundamentally different from its single-crystalline counterpart, and therefore, we redesign the process flow to nearly eliminate the Schottky barrier height at the metal-MoS2 contact. The resulting MoS2 field-effect transistors exhibit mobilities of 21 cm2 V-1 s-1, contact resistances of 3.8 k Omega mu m and on-current densities of 120 mu A mu m-1, which are similar to those achieved with single-crystalline flakes. A method for integrating polycrystalline molybdenum disulfide using processes in a 200 mm fab facility can create transistors with high robustness and performance comparable with single-crystalline devices.