Nano and Sub-nano Scale Friction Behavior in Rotary Processing of 6H-SiC with Different Off-Axis Angles

The requirements for the surface quality of monocrystal SiC wafers as the representatives of third-generation semiconductors have been raised to a sub-nanometer/nanometer scale (SN/N scale), i.e., few tenths of nanometer to few nanometers. To meet wafer processing needs at these scales, it is essential to understand microscopic wear behavior and material deformation mechanism between the abrasive and the SiC substrate. Large-scale molecular dynamics simulation technology has the unique advantages in the analysis of microscopic interactions. In this paper, a series of wear behaviors and material removal mechanisms in rotary motion machining processes are analyzed for three types of available commercially 6H-SiC crystals with different off-axis angles (0°, 4°, and 8°). The relationship between the micro-friction coefficients and processing parameters (off-axis angle, cutting distance, and depth of cut) is studied. At the same time, slip deformation mechanism, abrasive wear behavior, and maximum subsurface damage depth of 6H-SiC are analyzed in detail. The results of the current work are of great significance for understanding the interaction mechanisms between diamond abrasives and SiC wafers under SN/N scale conditions.