Growth of semipolar {20-21} GaN and {20-2-1} GaN for GaN substrate

In this article, we present a semipolar {20–21} GaN layer and {20–2–1} GaN layer for large GaN substrates. The {20–21} GaN layer was fabricated on {22–43} patterned sapphire substrates (PSSs) by metal‐organic vapor‐phase epitaxy (MOVPE) and hydride vapor‐phase epitaxy (HVPE). We found that the surface roughening and crack generation during the HVPE growth were suppressed by the formation of SiO2‐striped masks parallel to the c‐axis on the MOVPE‐grown {20–21} GaN template. Furthermore, we demonstrated millimeter‐thick crystal growth on a {20–21} GaN layer and a {20–2–1} GaN layer on a GaN substrate using HVPE. The dark‐spot density in the {20–2–1} GaN layer was approximately 9.6 × 106 cm−2 for 960 min growth. The dark‐spot density in the {20–2–1} GaN layer decreased more rapidly than that in the {20–21} GaN layer as growth thickness increased.