Point defects in thermal GaAs/GaAs-oxide structures probed by electron paramagnetic resonance

Abstract

Display Omitted We have carried out a multifrequency conventional ESR study of thermally oxidized GaAs.The results reveal the generation of AsGa+ antisite defects upon thermal oxidation.Another defect observed is hypothesized as originating from the GaAs-oxide film.We report on the observation of other centers, including substitutional Fe in the GaAs substrate. A low-temperature electron spin resonance investigation has been carried out on thermally oxidized semi-insulating (Fe compensated) GaAs, with the intent to assess atomic scale information on predominant intrinsic point defects inherently generated as a result of thermal oxidation. For powders thermally oxidized in the range Tox=350-615?C, the study reveals the presence of various spectra. This includes the four-line EL2 defect spectrum centered at g~2.043 and characterized by the isotropic hyperfine constant Aiso~910G, ascribed to the 75AsGa+ antisite defect. The defect is found to be substantially generated through oxidation, in line with theoretical expectation; It is not observed in the as-received non pulverized parent c-GaAs wafer. Additional signals have been isolated, including one characterized by g~2.063, which is tentatively assigned as originating from a point defect residing in the thermal GaAs-oxide film. The results are discussed within the context of theoretical insight and previous experimental assessment of GaAs interfaces.