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 ion s (oxygen, magnesium, argon, zinc, krypton, xenon) at various energies (0.13-5.7 GeV). From the DLTS spectrum, the introduced defects are sh own to be paint defects, similar to those obtained by fast electron an d neutron irradiation, This study is concerned with extended results o btained 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 diff erent ions and different energies shows a small dispersion for epitaxi al material but a large one for LEC GaAs. The variations seem to be co rrelated with the electronic stopping power S-e (in the range 1-20 MeV /mu m) and suggest a slight defect annealing by electronic excitation.