Controllable Material Removal via Diffusion-Assisted Etching at the Atomic Scale

Abstract Atomically precise processing reflects the scientific community’s relentless pursuit of manufacturing at atomic and close-to-atomic scales. This study presents a metal-film-assisted laser processing method that enables highly controllable material removal with angstrom-depth resolution. Laser-induced modifications of atomic-scale thickness on Au/4H-SiC surfaces are investigated under ambient air conditions. Through selective etching of the modified layer, three stages of material removal—from the nanometric to the atomic scale—are developed, and their underlying mechanisms are revealed for the first time. The metal-film-assisted surface processing mechanism is investigated using a two-temperature model-based molecular dynamics approach with a dual-electron temperature grid. Results indicate that the presence of an Au film significantly lowers the damage threshold of the substrate due to diffusion effects. The removal mechanisms across the three stages are discussed, highlighting the critical role of the Au film in enabling nanometric laser-based surface processing. Furthermore, the interaction between the laser and the Au/4H-SiC heterostructure is analyzed through atomic simulations and experimental investigations. The removal of the Au layer is primarily attributed to photomechanical spallation. As laser energy increases, the substrate surface undergoes doping modification, melting and re-solidification, vaporization, and phase explosion. This method, offering atomic-scale resolution and lattice patterning capabilities, paves the way for atomic and close-to-atomic scale manufacturing.