Experimental study by ''in situ'' resistivity measurements of swift heavy ion induced defects in GaAs crystals

Gallium arsenide thin crystals were irradiated at GANIL with swift ions (oxygen, magnesium, argon, zinc, krypton, xenon) at various energies (0.13-5.7 GeV). From the DLTS spectrum, the introduced defects are shown to be paint defects, similar to those obtained by fast electron and neutron irradiation, This study is concerned with extended results obtained from ''in situ'' resistivity measurements during 300 and 77 K irradiation, The investigated materials are LEC grown (Si-doped n-type and Zn-doped p-type) thinned crystals (6-300 mu m thick) and, for the first time, epitaxial MOCVD n-type GaAs grown on SI GaAs substrates. Comparison of the various resistivity-fluence curves obtained for different ions and different energies shows a small dispersion for epitaxial material but a large one for LEC GaAs. The variations seem to be correlated with the electronic stopping power S-e (in the range 1-20 MeV/mu m) and suggest a slight defect annealing by electronic excitation.