The [010] tilt low angle grain boundaries in bulk β-Ga2O3 crystals grown by EFG method

Abstract

High crystal quality in both the substrate and epitaxy ensures the performance and stability of semiconductor devices. However, due to its low symmetry structure, a variety of crystal defects are easily formed in β-Ga₂O₃. Specifically, low angle grain boundaries (LAGBs) can limit the single crystal size of the β-Ga₂O₃ substrate, thereby reducing the yield of single crystal substrates. In this work, [010] tilt LAGBs were observed on the surface of (010) β-Ga₂O₃ wafer following wet chemical etching, and the etching morphology of the [010] tilt LAGBs showed “bending line segment”. The orientation analysis of the (010) β-Ga₂O₃ wafer indicates that most of the [010] tilt LAGBs in β-Ga₂O₃ bulk crystals have orientation difference angles of <2°. Transmission electron microscope (TEM) results indicate the presence of edge dislocations in the vicinity of [010] tilt LAGBs. The geometric shape of [010] tilt LAGBs in β-Ga₂O₃ crystals was obtained, and the formation mechanism was explained in conjunction with the crystal growth mechanism. Furthermore, [010] tilt LAGBs can result in the appearance of double peaks in X-ray rocking curves due to their capacity to disrupt the integrity of single crystals and to cause orientation differences between grains.