Improvement of Contact Resistance and 3D Integration of 2D Material Field‐Effect Transistors Using Semi‐Metallic PtSe₂ Contacts

Abstract In this work, the potential of 2D semi‐metallic PtSe₂ as source/drain (S/D) contacts for 2D material field‐effect‐transistors (FETs) through theoretical and experimental investigations, is explored. From the density functional theory (DFT) calculations, semi‐metallic PtSe₂ can inject electrons and holes into MoS₂ and WSe₂, respectively, indicating the feasibility of PtSe₂ contacts for both n‐ and p‐metal‐oxide‐semiconductor FETs (n‐/p‐MOSFETs). Indeed, experimentally fabricated flake‐level MoS₂ n‐MOSFETs and WSe₂ p‐MOSFETs exhibit a significant reduction in contact resistance with semi‐metallic PtSe₂ contacts compared to conventional Ti/Au contacts. To demonstrate the applicability for large‐area electronics, MoS₂ n‐MOSFETs are fabricated with semi‐metallic PtSe₂ contacts using chemical vapor deposition‐grown MoS₂ and PtSe₂ films. These devices exhibit outstanding performance metrics, including high on‐state current (≈10⁻⁷ A/µm) and large on/off ratio (>10⁷). Furthermore, by employing these high‐performance MoS₂ n‐MOSFETs, vertically stacked n‐MOS inverters are successfully demonstrated, suggesting that 3D integration of 2D material FETs is possible using semi‐metallic PtSe₂ contacts.