Silicon-processes-compatible contact engineering for two-dimensional materials integrated circuits

Two-dimensional (2D) semiconductors, especially transition metal dichalcogenides (TMDCs), have been proven to be excellent channel materials for the next-generation integrated circuit (IC). However, the contact problem between 2D TMDCs and metal electrodes has always been one of the main factors restricting their development. In this review, we summarized recent work on 2D TMDCs contact from the perspective of compatible integration with silicon processes and practical application requirements, including the contact performance evaluation indicators, special challenges encountered in 2D TMDCs, and recent optimization methods. Specifically, we sorted out and highlighted the performance indicators of 2D TMDCs contacts, including contact resistance (R_C), contact scaling, contact stability, and contact electrical/thermal conductivity. Special challenges of 2D TMDCs and metal contact, such as severe Fermi level pinning, large R_C, and difficult doping, are systematically discussed. Furthermore, typical methods for optimizing 2D TMDCs R_C, edge contact strategies for scaling contact lengths, and solutions for improving contact stability are reviewed. Based on the current research and problems, the development direction of 2D TMDCs contacts that meet the silicon-based compatible process and application performance requirements is proposed.