Van der Waals Interface Engineering for Enhancemen of Semiconductor Device Performance

Since the performance of semiconductor devices is highly dependent on charge injection between the metal electrode and the semiconductor channel, it is important to reduce defect density through interfacial engineering at the metal-semiconductor interface. Typically, as metal is directly deposited on the semiconductor surface to form the contact electrode, metal atoms can diffuse into the semiconductor lattice and degrade the charge injection performance. In this study, we propose a method to insert a WSe₂layer to reduce the defect density at the metal/semiconductor interface. The WSe₂ layer inserted at the metal/semiconductor interface acts as a diffusion barrier to prevent the diffusion of metal atoms into the semiconductor lattice, thereby suppressing structural defects. The metal/WSe₂/Si diode is fabricated by transferring a WSe₂ layer thermally grown on a SiO₂ substrate to a p-type Si substrate by a wet transfer method and then depositing metal electrodes (Ni, Ag, Ti, Cr/Au) onto the WSe₂/Si substrate using an E-Beam evaporator. The C-V (Capacitance-Voltage) characteristics of the diodes confirm that the insertion of the WSe₂ layer induces a low interfacial defect density (D_it). Furthermore, the I-V (Current-Voltage) characterization of the diodes shows that the WSe₂ layer not only provides a diffusion barrier but also reduces the leakage current and improves the stability, thereby improving the overall diode performance. In conclusion, the interfacial control method with WSe₂ layer insertion proposed in this work provides a strategy to overcome the challenges of 2D material-based Si semiconductor technology aimed at improving performance and reliability.