Conformal deposition of WS2 layered film by low-temperature metal-organic chemical vapor deposition

Large area multi-layer WS2 film has high potential as a channel material for MOSFETs in next-generation LSIs. State-of-the-art LSIs have complex three-dimensional (3D) structures such as vertical channels and multi-layer stacked channels surrounded by gate electrodes. To develop such structures, it is desirable to fabricate channel layers by CVD, which is suitable for conformal deposition along a substrate with a complicated 3D structure. In this study, we report on WS2 films deposited by Metal-Organic CVD using low-toxicity n-BuNC-W(CO)5 as a liquid tungsten precursor and (t-C4H9)2S2 for sulfur precursor. The deposited films have a roughly stoichiometric composition and are stable even after 60 d of shelf time in air atmosphere. A layered film along the 3D fin substrate parallel to the surface was fabricated on the entire structure.