Abstract: To deeply understand the material removal mechanisms at the atomic level in the process of chemical mechanical polishing (CMP) of silicon carbide (SiC) under ultrasonic vibration conditions, molecular dynamics (MD) method was employed to establish an atomic model of SiC scratched by a diamond abrasive, and the crystal structure, temperature, normal and tangential forces of SiC during the scratching process were investigated. The effects of ultrasonic vibration frequency on the scratched surface quality and material removal rate of SiC in the scratching process were also analyzed. Simulation results indicate that during the cutting process, amorphization appears in the local area of processed SiC surface. The introduction of ultrasonic vibration to the SiC scratching process can alleviate the average tangential force and the average normal force of the imposed abrasive, which is beneficial to the scratching process and the improvement of scratched surface quality. For the given simulation parameters, the best ultrasonic vibration frequency which can lead to a better polished surface quality and higher material removal rate is 80GHz, above which the surface quality and material removal rate are less affected by the ultrasonic vibration.

Key words: silicon carbide (SiC), scratching, ultrasonic vibration, molecular dynamics mothod