Comparison of Ga2O3 Films Grown on m- and r-plane Sapphire Substrates by MOCVD

Ga 2 O 3 films were respectively deposited on m- and r-plane sapphire substrates by LP-MOCVD. The growth pressure greatly influenced the surface morphology and the grain shape, and the grain size obviously decreased with the increasing growth pressure. XRD results indicated that a higher growth pressure helped to suppress the polycrystalline orientation of β -Ga 2 O 3 films grown on m-plane sapphire substrates, but was not conducive to the formation of α -Ga 2 O 3 . Ellipsometer measurement shows that the higher growth pressure will slow down the growth rate, and the deposition rate on the r-plane was significantly faster than the m-plane under the lower growth pressure. The bandgap obtained by fitting the optical absorption spectrum was also consistent with the previous reports.