Wear behaviors and plastic deformation mechanisms induced by nano-grinding of indium-doped gallium nitride single crystal

Abstract

The wear behaviors and plastic deformation mechanisms of indium (In)-doped gallium nitride (GaN) induced by nano-grinding are investigated in this work, which is of great significance for improving the quality and precision of the machined surface of the nitride semiconductor, as well as for elucidating their mechanical properties during the nano-grinding process. A numerical simulation approach based on molecular dynamics (MD) is used to carry out a comparative analysis of the nano-grinding process for the undoped and In-doped GaN by analyzing the machined surface morphology, formation mechanisms of the subsurface damage (SSD) layer, dislocation behaviors, and residual stress. In addition, the effects of material temperature and grinding speed on the nano-grinding process of the In-doped GaN are investigated. Compared to the undoped GaN, indium doping increases the pile-ups and chips on both sides of the abrasive, the roughness of the machined surface, and the coefficient of friction. Moreover, it reduces the thickness of the SSD layer and restricts the occurrence of phase transformations. Indium doping also weakens the dislocation interactions and reduces the generation of dislocation entanglements as well as wall-like dislocations. Furthermore, it decreases the maximum value of the residual stress and increases the area of high residual stress regions. The wear behaviors and plastic deformation mechanisms of In-doped GaN are quite sensitive to material temperature, but not much influenced by grinding speed.