IMPROVED STABILITY OF C-DOPED GAAS GROWN BY CHEMICAL BEAM EPITAXY FORHETEROJUNCTION BIPOLAR-TRANSISTOR APPLICATIONS

Carbon-doped GaAs epitaxial layers were grown by chemical beam epitaxy using trimethylgallium and arsine as growth precursors. The behaviour of incorporated hydrogen as a function of the carbon doping level, an nealing conditions and growth temperature has been investigated. The e pilayers were characterized by Hall measurements, secondary ion mass s pectrometry, Raman spectroscopy and time-resolved photoluminescence. T he degradation of minority carrier lifetime for C-doped GaAs is shown to be more drastic as the carbon concentration and annealing temperatu re are increased. Despite the use of tri-methylgallium, only a small a mount of C-H complexes were observed in the epilayers. High growth tem peratures to remove the remaining hydrogen and their impact on heteroj unction bipolar transistor stability have been also investigated.