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

Abstract

Ga2O3 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-Ga2O3 films grown on m-plane sapphire substrates, but was not conducive to the formation of α-Ga2O3. 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.

Influence of Oxygen on β-Ga2O3 Films Deposited on Sapphire Substrates by MOCVD

“…6,15,26 In our previous work, we deposited and investigated a series of Ga 2 O 3 films on different substrates. We analyzed the influence of growth temperature or growth pressure on the crystal phase and orientation of Ga 2 O 3 films deposited on m− or r-plane sapphire substrates, 27,28 and found that the increase in growth pressure can supress the growth rate and grain size of β-Ga 2 O 3 films on sapphire substrate. 29,30 We also investigated the Ga 2 O 3 films deposited on the epi-GaN/sapphire substrates, and it still grew preferentially along the (−201) crystal plane family at higher growth temperatures.…”