The anisotropy dependence of deformation mechanism of cleavage planes in β-Ga2O3 single crystal

Abstract

β-Ga2O3 is a promising ultra-wide bandgap semiconductor. The deformation of β-Ga2O3 was few investigations, especially on the cleavage planes which hindered the high-efficiency and low-damage manufacturing of β-Ga2O3 wafers. Here, the anisotropy dependence of mechanical response and deformation mode of the (100) and (001) cleavage planes in β-Ga2O3 single crystal were studied by the nanoindentation method. The results showed that a broad deformation zone was formed on the subsurface of the β-Ga2O3 wafer after unloading, which was dominated by slippage, dislocations, stacking faults, and cracks. Cross stacking faults were found on the subsurface of the (100) plane. Under the same load condition, the damaged zone depth of the (001) plane was twice that of the (100) plane. At the same time, two kinds of cracks with different angles were found on the subsurface. The direction of the crack is related to stress distribution. The crack propagation mechanism transitioned to brittle cleavage fracture within the loading process. The crack did not extend to the indentation surface of the (100) plane. These results revealed the mechanism of deformation and damage in the manufacturing of low-symmetry β-Ga2O3 wafers.