Growth and characterization of LiGaO2 substrate crystal for GaN epitaxy

Abstract We report Czochralski growth of LiGaO 2 single crystals, which are promising substrate materials for the epitaxy of GaN since the lattice mismatch between LiGaO 2 and GaN is only 0.9%. The dislocation etching pits morphologies and distribution characteristics were well revealed by chemical etching technique. Transmission electron microscopy (TEM) observations showed that γ-Ga 2 O 3 inclusions tended to emerge in LiGaO 2 crystals owing to the volatilization of Li 2 O during growth process. Therefore, many edged dislocations were induced, which usually lie on (0 0 1) plane. The amount of γ-Ga 2 O 3 inclusions is closely related to growth parameters. X-ray topography shows that an interface parallel to (0 0 1) tends to form in the LiGaO 2 crystals pulled along (1 0 0). The two parts aside the (0 0 1) interface were slightly rotated around the interface normal. The crystal quality can be improved by using starting materials with excess of Li 2 CO 3 and adopting appropriate growth parameters.