Impact of vacuum anneal at low temperature on Al2O3/In-based III-V interfaces

► AR-XPS is used to investigate the interface between Al2O3 and III-V substrates. ► No interfacial oxide is observed on InGaAs after anneal under UHV at 600 °C. ► A clear difference is reported regarding indium oxidation under vacuum at 400 °C. ► Indium hydroxide is formed only on InAs, in contrast with InP and InGaAs. ► On InP, a transition from InPOx to POx is observed after anneal at 400 °C.