Abstract
Defects, such as scratches, cleavage fracture, and cleavage pit, occur during surface processing and affect the surface integrity of β-Ga2O3(100) substrates. This study analyzed the effects of polishing materials (polyurethane, lead, and copper) and substrate surface temperatures (25, 10, and 0 ℃) on the polishing results to overcome the effects of such defects on the substrates. Vickers indentation test was used to detect the effects of the material and surface temperature on the hardness of the disc and substrate, respectively. Machining was verified by conducting ball-disk friction wear and polishing experiments. The experimental results indicate that the material of the polished optical disc significantly affected β-Ga2O3(100) during surface processing. The higher the hardness of the polished optical disc, the greater is the material removal rate (MRR) of substrate surface, and more serious is the surface cleavage phenomenon. A lead disc with lower hardness can be used to process β-Ga2O3(100) for realizing a higher MRR, thereby effectively avoiding cleavage fractures and obtaining a surface roughness (Ra) and scratch depth of 3.4 nm and 18 nm, respectively. The hardness and mechanical strength of the substrate can be enhanced at low temperatures, and the indentation depth becomes smaller under the action of external forces, effectively inhibiting the formation of scratches and pits on the surface of the substrate during polishing. After polishing the substrate at 0 ℃, the Ra, scratch depth, and total number of cleavage pits were 2.2 nm, 14.3 nm, and 246, respectively. Compared with 25℃, Polishing the substrate at 0 ℃ decreased the Ra, scratch depth, and number of cleavage pits by 35.3, 20.6, and 34.9%, respectively. At 0 ℃, the substrate effectively avoided cleavage fracture and inhibited scratch and pit formation, thereby significantly improving the polishing effect.