HIGH-RESISTIVITY AND PICOSECOND CARRIER LIFETIME OF GAAS IMPLANTED WITH MEV GA IONS AT HIGH FLUENCES

Rutherford backscattering spectrometry-channeling, double-crystal x-ra y diffraction, optical absorption studies, and electrical measurements have been carried out on 2 MeV Ga-implanted GaAs at fluences of 1 x 1 0(15) and 5 x 10(15) cm(-2). Implanted samples exhibited a strain fiel d associated with implantation-induced damage, low resistivity due to hopping conduction and mobilities of about 1 cm(2)/V s. Annealing of t hese samples at 600 degrees C caused substantial recovery of postimpla nt damage and an increase of resistivity of more than four orders of m agnitude, with mobility up to about 2600 cm(2)/V s. Photocarrier lifet ime of annealed samples is in the few picoseconds range. These propert ies are strikingly similar to those of arsenic implanted GaAs, suggest ing that arsenic precipitates are unlikely to be solely responsible fo r short carrier lifetime in the latter case. Thus Ga-implanted GaAs ma y be an interesting prospect for fast optoelectronic device applicatio ns. (C) 1995 American Institute of Physics.