Interface control of Gd₂O₃/GaAs system using pre-deposition of Gd metal on GaAs substrate with native oxides

Ultrathin Gd metal was evaporated on GaAs surface covered with native oxides. X-Ray photoelectron spectroscopic studies revealed that GaAs-native oxides could be reduced during the deposition of Gd metal. However, the elemental forms of Ga and As were not observed but the oxidation of Gd metal was confirmed from LMM Auger electron spectra, Gd 3d _5/2, and O 1s photoelectron spectra. The Gd coated GaAs substrates were heated at 400 °C and Gd₂O₃ films were successively deposited with a well developed crystalline state. This reductive metal deposition prior to oxide formation improved interfacial quality of GaAs without previous chemical etching or passivation. Capacitance-voltage (C-V) measurements at 1 MHz indicated that a good interfacial state between Gd₂O₃ and GaAs could be obtained appropriate for metal-oxide-semiconductor (MOS) applications through a two step deposition of Gd and Gd₂O₃.