Atomistic Investigation of Material Removal and Damage Evolution during Transverse Ultrasonic Vibration-Assisted Nanoscratching of InP Wafers.

Indium phosphide (InP), a key substrate for high-frequency electronic and optoelectronic devices, is highly vulnerable to machining-induced damage. Although ultrasonic vibration provides a promising strategy for low-damage machining of InP, the underlying atomistic mechanisms remain insufficiently understood. In this study, molecular dynamics simulations of InP(001) nanoscratching combined with single-abrasive-grain scratching experiments were conducted to compare conventional scratching (CS) and transverse ultrasonic vibration-assisted scratching (UVS) at different scratching depths. The results show that transverse ultrasonic vibration periodically modulates the lateral interfacial interaction, induces alternating lateral forces, and redistributes the contact load, thereby reducing the tangential and normal forces, the friction coefficient, the shear strain concentration, and the residual deformation. Although UVS reduces the mechanical loading, the extended sliding trajectory and repeated lateral shearing enhance interfacial energy dissipation, leading to a higher temperature than under CS. Increasing scratching depth enhances material pile-up and atomic removal, but also intensifies surface and subsurface damage. Compared with CS, UVS promotes a more balanced redistribution of material across the groove, reduces surface roughness by approximately 46%, and suppresses the propagation of dislocations, stacking faults, and structurally disordered regions into the deeper subsurface. Experimental results further support the surface damage suppression trend and damage evolution characteristics revealed by the simulations, with the maximum surface damage width measured under UVS decreasing from 141 to 96 μm, corresponding to a reduction of approximately 32%. These findings reveal the atomistic mechanisms governing material removal and damage evolution under transverse ultrasonic vibration and provide theoretical guidance for low-damage machining of InP wafers.