Investigation of defect structure in homoepitaxial (2¯01) β-Ga2O3 layers prepared by plasma-assisted molecular beam epitaxy

We report growth and comprehensive study on structural properties of homoepitaxial (2¯01) β-Ga2O3 layers grown by plasma-assisted molecular epitaxy. Effects of growth temperature on surface morphology, crystal quality of homoepitaxial β-Ga2O3 layers were investigated in detail. Characterization indicates that the growth temperature plays an important role on both of surface morphology and the crystal quality of the homoepitaxial β-Ga2O3 layers. Characteristic of defects in homoepitaxial (2¯01) β-Ga2O3 layers was investigated comprehensively. Two types of defects were found out including threading dislocation and twin boundary. Origin and formation mechanism of these defects were clarified. The densities of the twin boundary and dislocation based on growth temperature are investigated and discussed. As the growth temperatures changed from 750 to 850 °C, the densities of the threading dislocation etch pit changed from 1.1 × 106–6.6 × 105 cm−2, while those of the twin boundary defect changed from 7.5 × 103–2.1 × 102 cm−1. It is clear that while the densities of the twin boundary were dramatically reduced by 35 times, the densities of the threading dislocation were reduced by 1.7 times.