The lattice distortion of β-Ga2O3 film grown on c-plane sapphire

Abstract

The β-Ga2O3 film is grown on c-plane sapphire (Al2O3) substrate using metal organic chemical deposition method. According to high resolution X-ray diffraction measurement results, the epitaxial relationship between β-Ga2O3 film and c-plane sapphire was confirmed. The β-Ga2O3 film is (\( \overline{2} 01 \)) preferred orientation and β-Ga2O3 〈102〉 and 〈010〉 directions are parallel to Al2O3 〈\( 1\overline{1} 0 \)〉 and 〈110〉, respectively. Meanwhile, the Bragg diffraction angles of β-Ga2O3 (\( \overline{2} 01 \)), (\( \overline{4} 01 \)), (111) and (\( \overline{1} 11 \)) planes are carefully measured. Using interplanar spacing equation and Bragg equation, the actual β-Ga2O3 lattice constants were calculated. The results show that lattice constants b and angle β become larger, but the constant a, c becomes smaller. This suggests that it is difficult to growth high quality β-Ga2O3 film with just one type of β-Ga2O3 crystal grains on the Al2O3 substrate due to the mismatch of crystal structure and lattice constants.