The dynamics of thermal annealing in arsenic-ion-implanted GaAs

The effect of thermal annealing on the surfaces of arsenic-ion-implanted GaAs has been investigated by transmission electron microscopy, deep level transient spectroscopy and temperature-dependent resistance measurements. For the annealed films of arsenic-ion-implanted GaAs arsenic precipitates and a band of deep-level defects with the activation energy of around 0.6 eV near the surface are observed. The mean size and concentration of As precipitates in samples implanted at a dosage of 10(16) cm(-2) are about 2-3 nm and 7 x 10(16) cm(-3), respectively. The cross section of the deep level defects near the surface is calculated to be 7 x 10(-14) cm(2). The carrier-transport mechanisms of both as-implanted GaAs and post-annealed GaAs are shown dominantly to be hopping type conduction and active type conduction, respectively.