The removal mechanism and force modelling of gallium oxide single crystal in single grit grinding and nanoscratching. (15th August 2021) - Wang, Yongqiang
Highlights: Single grit grinding and nanoscratching revealed that the material removal of monocrystalline β-Ga2 O3 was affected by its crystal orientation. The ductile removal of (010) β -Ga2 O3 was dominated by the formation of stacking faults, and its brittle removal was due to the initiation of microcracks. A complete force model was developed to elucidate the removal mechanism involved in single grit grinding. The modelling results could determine the critical thresholds for chip formation and brittle removal. Abstract: Gallium oxide (Ga2 O3 ) single crystals are an ultrawide bandgap semiconductor with wide industrial applications. Ultra-precision grinding is an essential shaping process in the fabrication of high quality Ga2 O3 substrates. However, due to the lack of understanding of their removal mechanism, the development of high efficiency and low-damage grinding technology for Ga2 O3 substrates faces great challenges. In this work, the removal mechanism of (010) β -Ga2 O3 was systematically investigated by use of single grit grinding and nanoscratching. The results showed that its removal involved both ductile cutting and brittle fracture under conventional grit-grinding conditions. The ductile deformation of β -Ga2 O3 was dominated by the formation of stacking faults, while in its brittle removal region microcracks were initiated and propagated mainly along the (200) lattice plane. A theoretical force model that reflects the combined effects of ductile and brittle removal was developed to further elucidate the removal mechanism. The calculated force was in good agreement with the experimental results, clearly indicating that the transition of removal modes was affected by the chip cross-sectional area. Graphical abstract: Image, graphical abstract