Polishing process of 4H-SiC under different pressures in a water environment

Considering that the polishing process cannot be performed without water, a polishing model for 4H-SiC in a water environment is established. The influence of pressure on the 4H-SiC polishing process in a water envi-ronment is investigated using molecular dynamics simulations. The simulations indicate that the 4H-SiC sub-strate is completely compressed without phase transformation owing to the pressure imposed by the water film. Making contact with abrasives is the main reason for phase transformation, and an increase in polishing pressure leads to a significant increase in temperature and the number of phase transformations. An increase in pressure can increase the friction force; however, it does not increase the friction coefficient because the water film bears partial pressure. In addition, an increase in polishing pressure promotes basal slip in the 4H-SiC substrate, resulting in dislocations and structural damage. However, the number of chip atoms does not always increase with increasing pressure. After the polishing pressure reaches a certain value, an increase in pressure degrades the machining quality and does not improve the material removal rate. The atoms with a defect structure are partially recovered after unloading, but the dislocations are not significantly reduced. These findings can provide theoretical guidance for the selection of polishing pressure.

Automated summary

A polishing model for 4H-SiC in a water environment is established, and the influence of pressure on the polishing process is investigated using molecular dynamics simulations. The simulations show that the pressure imposed by water film compresses the 4H-SiC substrate without phase transformation. Contact with abrasives leads to phase transformation, and increasing pressure results in higher temperature and more phase transformations. Basal slip and structural damage occur under increased pressure.