Optical behavior of the U band in relation to EL2 and EL6 levels in boron-implanted GaAs

The majority-carrier optical emission cross section and the concentrations of the levels induced by boron implantation at 1010 ions/cm2 in GaAs have been obtained usng a new optical isothermal capacitance transient spectroscopy in the photon energy range 0.8–1.4 eV. The experimental optical data obtained at different annealing temperatures show only the presence of the EL2 and EL6 electron trap levels. Moreover, they are in complete agreement with the existence of an interaction between these two deep trap levels. Besides, this interaction has been found to be at the origin of U band in the deep level transient spectroscopy (DLTS) spectra and of the anomalous dependence on the annealing temperature of the level concentrations deduced from the optical technique and DLTS spectra. off