High-temperature thermal stability study of 1 nm Al₂O₃ deposited on InAs surfaces investigated by synchrotron radiation based photoemission spectroscopy

High-resolution soft x-ray photoemission spectroscopy (SXPS) has been used to study the high-temperature thermal stability of ultra-thin atomic layer deposited (ALD) Al₂O₃ layers (∼1 nm) on sulfur passivated and native oxide covered InAs surfaces. While the arsenic oxides were removed from both interfaces following a 600 °C anneal, a residual indium oxide signal remained. No significant differences were observed between the sulfur passivated and native oxide surfaces other than the thickness of the interfacial oxide layer while the Al₂O₃ stoichiometry remained unaffected by the anneals. The energy band offsets were determined for the Al₂O₃ on the sulfur passivated InAs surface using both valence band edge and shallow core-level photoemission measurements. (paper)