This paper has studied the electrical and interfacial properties of atomic-layer-deposited Al2O3 thin film on ammonium-sulfide passivated GaAs. It was found that the Al2O3 deposited at 300°C relative to that at 100°C showed the nearly four orders of magnitude reduction in gate leakage current at the capacitance-equivalent-thickness of 40 Å. The capacitance-voltage (C-V) characteristics displayed the higher oxide capacitance, reduced frequency dispersion and less charge trapping when GaAs receiving (NH4)2S sulfide immersion; these improvements can be reasonably explained by the suppression of both native oxides and the resultant improved interface quality. Annealing as-deposited Al2O3/GaAs structures at high temperatures further reduces the Fermi level pinning effect on accumulation capacitance, however, causes an increase in C-V frequency dispersion and gate leakage current. We suggested that these phenomena are strongly associated to the amount of As-related defects resided at the dielectric/substrate interface during thermal desorption.
|Journal||Journal of Physics: Conference Series|
|Issue number||Part 4|
|State||Published - 27 Mar 2008|
|Event||17th International Vacuum Congress, IVC 2007, 13th International Conference on Surface Science, ICSS 2007 and International Conference on Nanoscience and Technology, ICN+T 2007 - Stockholm, Sweden|
Duration: 2 Jul 2007 → 6 Jul 2007