We report on the effect of vacuum anneal on interfacial oxides formed between Al2O3 and III-V semiconductors. On InGaAs, no interfacial oxide is detected after annealing at 600 degrees C under UHV whereas annealing under secondary vacuum favours the regrowth of thin InGaOx interfacial oxide. Lowering the temperature at 400 degrees C highlights the effect of III-V substrates since In-OH bonds are only formed on InAs by OH release from TMA/H2O deposited alumina. On InGaAs, regrowth of InGaOx is observed, as a result of preferential oxidation of Ga. On InP, a transition from InPOx to POx is highlighted. (C) 2012 Elsevier B.V. All rights reserved.