Atomic simulation of the temperature effect on fabrication mechanism of micro-structured surface on single-crystal silicon

Micro-structured surfaces have numerous applications in various fields. Thermal-assisted machining (TAM) is a promising solution for fabrication of micro-structured surfaces on brittle materials like single-crystal silicon. However, rare research focused on the fabrication mechanism of micro-structured surfaces during TAM and the effect of machining temperature on surface formation and subsurface damage remains unclear. In the present study, molecular dynamics (MD) simulation was conducted to investigate the machining mechanism of microstructured surface on single-crystal silicon via nano-scratching. The influences of machining temperature and former machined groove on surface formation and subsurface damage were discussed. The simulation results indicate that morphology of ridges on the uncut surface is greatly determined by the scratching direction. During the machining process, pile up on the machined surface is mainly caused by obstruction of the former machined groove and piling up of elastic recovery atoms. In the subsurface workpiece, machining from the following cut introduces negligible subsurface damage on the intersectional area. When the machining temperature raises, an increase in pile up is observed on the uncut surface and former machined groove. Less subsurface damage is generated and recrystallization of the disordered phases can be activated. In the intersectional area, the machining-induced defects can be partly eliminated by following processing at appropriate temperatures.