(10 1 ¯ 3)-oriented semipolar GaN growth on (10 1 ¯ 0) m-plane ScAlMgO₄ substrate

We report the growth of a GaN layer on a ( 10 1 ¯ 0 ) m-plane ScAlMgO₄ (SAM) substrate. The GaN layer demonstrated ( 10 1 ¯ 3 ) preference growth orientation. The anisotropy of the crystalline quality was distinctly observed through an X-ray rocking curve (XRC) taken across the sample surface over various azimuths across the orthogonal directions [0001] and [ 1 2 ¯ 10 ] of the SAM substrate. Notably, the crystalline quality exhibited gradual degradation as the substrate was rotated around its surface normal away from the c-direction [ 0 001 ] of the SAM substrate toward the a-direction [ 11 2 ¯ 0 ]. This degradation of the GaN layer was quantified by an increase in the XRC full width at half maxima for the 10 1 ¯ 3 XRC: starting from 1210 arcsec at 0° azimuth, deteriorating to its lowest crystallinity at 1512 arcsec at 60° azimuth, before a slight improvement to 1481 arcsec at 90° azimuth, followed by a symmetrical repetition of this pattern. Additionally, basal stacking faults in the 10 1 ¯ 3 -oriented GaN were observed along the [0001] direction using scanning transmission electron microscopy. Moreover, the selected area electron diffraction analysis was utilized to confirm the 10 1 ¯ 3 growth orientation that was found to be consistent with the X-ray diffraction result. The c-direction of the 10 1 ¯ 3 -oriented GaN layer was determined and it exhibited a metal face through integrated differential phase contrast imaging.