Large-Scale Fabrication of Submicrometer-Gate-Length MOSFETs with a Trilayer PtSe₂ Channel Grown by Molecular Beam Epitaxy

This article is the first report of MOSFETs fabricated on PtSe₂ grown by molecular beam epitaxy. Both material synthesis and device fabrication are done below 450 °C-the thermal budget of CMOS back-end-of-line processes. The MOSFETs are batch-fabricated by a CMOS-compatible process on 200-mm-diameter Si substrates prepared by a state-of-the-art BiCMOS foundry. With three monolayers of PtSe₂, an n-type MOSFET exhibits a current ON/OFF ratio of 43 at room temperature, which increases to 1600 at 80 K. These results are among the best of transistors based on synthesized PtSe₂. Despite the thin PtSe₂ layer, doping by contact bias lowers the contact resistance significantly and boosts the current capacity and the ON/OFF ratio. Temperature-dependent current-voltage characteristics imply a bandgap of approximately 0.2 eV, which confirms that the semiconductor-semimetal transition of PtSe₂ is not as abrupt as originally predicted. Better MOSFET performance can be expected by growing even thinner PtSe₂ uniformly and by thickening the PtSe₂ in the contact regions.