Growth and characterization of the β-Ga2O3 (011) plane without line-shaped defects

Abstract

A kind of dislocation occurring on the surface of the β-Ga₂O₃ (001) substrate and line-shaped defects caused by these dislocations in the epitaxial layer are responsible for the reverse leakage current and breakdown of power devices. Therefore, this type of dislocation is very disadvantageous for the performance of power devices, and the β-Ga₂O₃ (011) plane can effectively reduce or even completely avoid the influence of this defect due to its parallel relationship with this kind of dislocation. However, there is still a lack of systematic evaluation of the performance of this crystal plane. In order to determine whether the (011) plane is a potential substrate orientation, a series of (011)-oriented substrates were processed from β-Ga₂O₃ bulk crystals grown by the edge-defined film-fed growth (EFG) method to pursue further research. The high quality of the substrate was proved from the full width at half maximum (FWHM) of 66.79 arcsec in the X-ray rocking curve, and the wet etching method was used to study the dislocation distribution. The low-dislocation-density characteristic of the (011) plane was confirmed and the quadrilateral etch pit was observed by atomic force microscopy (AFM), which indicated that these etch pits were caused by other defects. In addition, the photoelectric properties and the element composition of the (011) plane were evaluated through Raman spectroscopy, optical transmittance spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results indicated that the (011) plane not only had a low-dislocation-density characteristic but also showed excellent photoelectric properties. At the same time, benefiting from the absence of the kind of dislocation mentioned above, the β-Ga₂O₃ (011) plane could be a potential substrate orientation for a high-quality epitaxial layer.