Published online by Cambridge University Press: 22 February 2011
Semi-insulating oxygen-doped GaAs layers have been grown by low pressure metalorganic vapor phase epitaxy (MOVPE) using aluminum-oxygen bonding based precursor diethyl aluminum ethoxide (DEALO). Resistivities of more than 2x109 Ω-cm at 294 K have been achieved. Deep level structure responsible for the high resistivity was investigated by deep level transient spectroscopy (DLTS) using DEALO and disilane co-doped GaAs p+-n homojunction. Multiple deep level peaks were observed, and the relative peak heights were found to vary with the dopant concentrations. Major deep levels were electron traps with ionization energy between 0.75 and 0.95 eV below conduction band edge minimum. An activation energy of 0.81 eV was deduced from temperature-dependent resistivity measurement, and should be closely related to the major0.75 eV peak in DLTS spectra.