PULSED LASER ANNEALING OF GAAS IMPLANTED WITH SE AND SI

Carrier activation and mobility were studied by Raman spectroscopy and the Hall effect in pulsed laser annealed samples of GaAs implanted with doses of Si and Se from 2.2 × 1012 to 6.0 × 1014 cm-2. The samples were annealed using a pulsed XeCl excimer laser (γ = 308 nm) and a pulsed dye laser (γ = 728 nm) with energy densities from 0.06 to 0.9 J/cm2 and pulse durations of about 10 ns. Very high carrier concentrations of 3 × 1019 and 1.5 × 1019 cm-3 were obtained for the best n-type GaAs samples annealed with the dye and excimer lasers, respectively. The dye laser consistently produced higher activation than excimer laser annealing. A transient reflectivity signal was used to identify the GaAs melt threshold and the melt phase dynamics of the GaAs under the nitride cap. The threshold energies for cap damage were 0.34 and 0.12 J/cm2 for the excimer and dye lasers, respectively. Raman spectroscopy was used to identify the threshold energies for the GaAs implant layer recrystallization and for optimum carrier activation.