Effect of indium as a surfactant in (Ga_(1-x)In_x)_2O_3 epitaxial growth on β-Ga_2O_3 by metal organic vapour phase epitaxy

摘要

(Ga_(1-x)In_x)_2O_3 epitaxial layers have been grown on (100) β-Ga_2O_3 substrates by metal organic vapour phase epitaxy (MOVPE). The process parameters were tuned in order to obtain an In-poor (Ga_(1-x)In_x)_2O_3 alloy, limiting the In incorporation below 3%. In this way it was possible to study the effect of In on the growth dynamics of Ga_2O_3. 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 Ga_2O_3 surface, delivering an effective surfactant effect.