Review of physicochemical-assisted nanomanufacturing processes for wide-bandgap semiconductor wafers

Nanomanufacturing involves not only fabricating nanoscale three-dimensional microstructures but also achieving nanoscale surface planarization and smoothing—an indispensable requirement in semiconductor-wafer processing. Wide-bandgap semiconductors such as SiC, GaN, diamond, and AlN combine high hardness, brittleness, and chemical inertness, making it exceptionally difficult to produce large size wafers with damage-free, atomic-level smoothness that meets the performance demands of next-generation devices. Physical–chemical composite methods, which marry the high-efficiency planarization of mechanical removal with the damage-free of chemical reactions, have emerged as the most promising route to overcome this challenge. Chemical mechanical polishing (CMP), the first-generation composite technique, was well established in industry; however, its low material removal rates, extensive consumable use, and environmental burden were increasingly problematic as wafer sizes grow and new wide-bandgap materials become mainstream. This review surveys the principal physicochemical processing techniques and examines four representative approaches—plasma-assisted polishing (PAP), plasma-based atomic-selective etching (PASE), catalyst-assisted etching (CARE), and electrochemical mechanical polishing (ECMP). A systematic comparison of their mechanisms, advantages, and limitations clarifies how these methods maintain crystal integrity while enabling selective material removal, thereby delivering atomically smooth surfaces with significantly higher throughput. The review provides both theoretical insight and practical guidance for cost-effective, atomically precise processing of wide-bandgap semiconductor wafers.