A study of Ar+ laser-assisted Si doping of GaAs by chemical beam epitaxy

Doping results from Ar+ laser-assisted chemical beam epitaxy with triethylg allium, tris(dimethylamino) arsenic, and silicon tetrabromide precursors ar e reported. Enhancements in the n-type doping concentration are observed wi th laser irradiation in the substrate-temperature range 390-500 degrees C. With a 300 W/cm(2) irradiation power density, a 70-fold increase in the car rier concentration is obtained at 390 degrees C substrate temperature. An e xpression for doping concentration is derived to assess the contribution of laser-induced thermal heating to the observed doping increase. Effects of photogenerated carriers on surface decomposition of metalorganic species ar e discussed. We postulate that the dramatic increase in carrier concentrati on at low growth temperatures is due to photolysis of silicon tetrabromide. (C) 2000 American Institute of Physics. [S0003-6951(00)04613-1].