We reported our observation results on the etch pit shapes on β-Ga₂O₃ (001) wafers using a scanning electron microscope (SEM) and an atomic force microscope (AFM) in a previous study. However, it was difficult to detect the internal crystal defects that exist under the etch pits. In this study, to gain a detailed understanding of the internal crystal defects under the etch pits in detail, we observed the etch pits on the (001) surface three-dimensionally using a focused ion beam–SEM. The etch pits investigated were “Cicada I” and “Cicada II,” which had the characteristic shapes observed in previous SEM and AFM analysis. Using this method, we revealed the existence of plate-like defects along the (100) plane under the etch pits. The proposed method is useful for understanding internal defects the etch pits which cannot be clarified by observing the surface using SEM and AFM analysis. Furthermore, from the changes in the SEM image contrast, Cicada I and Cicada II were deduced to be internal planar defects, i.e., plate-like voids and stacking faults, respectively.

我们报告了我们对β- Ga ₂ O ₃上的腐蚀坑形状的观察结果在先前的研究中，使用扫描电子显微镜（SEM）和原子力显微镜（AFM）制作（001）晶圆。然而，很难检测出存在于蚀刻坑下方的内部晶体缺陷。在这项研究中，为了详细了解蚀刻坑下方的内部晶体缺陷，我们使用聚焦离子束– SEM三维地观察了（001）表面上的蚀刻坑。所研究的蚀刻坑为“蝉I”和“蝉II”，具有先前的SEM和AFM分析中观察到的特征形状。使用这种方法，我们揭示了在蚀刻坑下方沿（100）平面存在板状缺陷的情况。所提出的方法对于理解蚀刻坑的内部缺陷是有用的，这些缺陷不能通过使用SEM和AFM分析观察表面来澄清。此外，