Effect of indium as a surfactant in (Ga1−xInx)2O3 epitaxial growth on β-Ga2O3 by metal organic vapour phase epitaxy

Abstract

(Ga1−xInx)2O3 epitaxial layers have been grown on (100) β-Ga2O3 substrates by metal organic vapour phase epitaxy (MOVPE). The process parameters were tuned in order to obtain an In-poor (Ga1−xInx)2O3 alloy, limiting the In incorporation below 3%. In this way it was possible to study the effect of In on the growth dynamics of Ga2O3. By varying the flow of the carrier gas (Ar) through the In precursor (trimethylindium) in a wide range, it was observed that for Ar/TMIn flows higher than a minimum threshold value, In was essential to obtain layers with very high crystal quality. The concentration of structural defects, such as stacking faults and twins, decreased dramatically and step-flow growth mode was achieved. These results have been explained by the tendency of In to float on the growing Ga2O3 surface, delivering an effective surfactant effect.