Generation-recombination low-frequency noise signatures in GaAs metal-semiconductor field-effect transistors on laterally oxidized AlAs

Low-frequency noise characteristics of GaAs-on-insulator metal-semiconductor field-effect transistors, for which the insulating buffer layer was produced by lateral wet-oxidation of AlAs, are studied. Devices with different gate widths were fabricated resulting in different overoxidation times for the AlAs layer. Three characteristic generation-recombination noise signatures are observed depending on the measurement temperature and the gate bias. A generation-recombination noise signature with energy level at E-c-0.69 eV is found to increase with the amount of overoxidation time. This near midgap trap shows an increase in concentration towards the oxide interface, and it is tentatively assigned to an arsenic-antisite-related defect known from previous studies as EB4. A possible mechanism for the formation and the microscopic origin of this defect are discussed. (C) 2003 American Institute of Physics.