Effect of high-temperature remelting on the properties of Sn-doped -Ga₂O₃ crystal grown using the EFG method

To increase the n-type conductivity of single-crystal substrates, the Sn element was purposefully inserted into & beta;-Ga2O3 crystals as n-type dopants. However, it was found that the color of the & beta;-Ga2O3 crystal changed significantly after high-temperature remelting in the edge-defined film-fed growth (EFG) method. According to Hall and optical transmission spectroscopy, the carrier concentration in the colorless region is significantly lower than that in the blue region, resulting in a decrease in electrical conductivity after high-temperature remelting of Sn-doped & beta;-Ga2O3. This is a challenge for the application of & beta;-Ga2O3 as an electronic power device. Therefore, we focused on the impact of the two color boundary areas on the structure, electronic, optical properties, and (100) surface defects after high-temperature remelting, and discussed the reason for this color change. Inductive coupled plasma emission spectroscopy (ICP) was used to detect the content of Sn. According to the results of high-resolution X-ray diffraction and atomic force microscopy, compared with the low crystal in the colorless area, the single crystal in the blue area showed higher crystal quality. The PL results indicate that the colorless area has more defects caused by oxygen vacancies than the blue area.