SURFACE CONDITION OF SI IMPLANTED GAAS REVEALED BY THE NONCONTACT LASER MICROWAVE METHOD/

The surface recombination of GaAs which has a heavily doped surface la yer formed by Si implantation and subsequent annealing has been invest igated using the noncontact laser/microwave evaluation method. The exp erimental results of the samples implanted with doses ranging from 1.0 x 10(11) to 3.9 x 10(12) cm(-2) at an energy of 100 keV indicate that the effective surface recombination velocity decreases with dosage be cause of the heavily doped layer formed after the annealing. On the ot her hand, the results of the samples implanted with a dose of 3.9 x 10 (12) cm(-2) at energies raging from 50 to 180 keV indicate that the ef fective surface recombination velocity increases with energy. This is mainly due to the decrease in the peak carrier concentration in the he avily doped layer.