Hafnia and alumina on sulphur passivated germanium

• HfO2 and Al2O3 films were grown by ALD technique.
• HfO2 and Al2O3were grown with and without sulphur passivation of the substrate.
• Both HfO2 and Al2O3 films were investigated by XPS. .
• Sulphur passivation of Ge is very effective in preventing the formation of the GeOx.

In this work hafnia (HfO2) and alumina (Al2O3) films were deposited on germanium, using either water or oxygen plasma as the oxidant, by atomic layer deposition at 250 °C with and without sulphur passivation of the substrate. X-ray photoelectron spectroscopy was carried out to investigate the interface between both HfO2 and Al2O3 films and germanium. The results show that for hafnia and alumina deposited with water on pre-sulphur treated germanium there is negligible GeOx formation when compared to films grown using oxygen plasma. The results support the case for sulphur passivation of the interface.