INVESTIGATIONS ON DEEP TRAPS IN GAAS AND (ALXGA1-X)AS BULK LAYERS GROWN BY METALORGANIC VAPOR-PHASE EPITAXY USING THE NEW ALTERNATIVE ARSENIC PRECURSOR DIETHYL-TERT-BUTYLARSIN

Metalorganic vapour-phase epitaxy (MOVPE) growth experiments for GaAs and (AlGa)As have been performed as a function of growth temperature and V/III ratio using the new alternative precursor diethyl-tert-butylarsin (DEtBAs) in combination with trimethylgallium (TMGa) and trimethylaluminium (TMAl). The incorporation of deep traps has been investigated by means of photoluminescence (PL) and deep level transient Fourier spectroscopy (DLTFS). In (AIGa)As layers grown with DEtBAs a drastic reduction of the deep broad band luminescence between 1.5 and 2 eV is observed in dependence of the growth conditions. A probably deep complex defect involving an As vacancy is observed in (AlGa)As layers grown with DEtBAs. In GaAs layers grown with DEtBAs or AsH3 the dominant deep trap is the EL2 defect. Deep level photoluminescence studies show a reduced incorporation of the EL2 defect as compared to AsH, grown layers, due to the smaller V/III ratio. The obtained low deep defect concentration in particular for GaAs layers underlines the great potential of the model precursor DEtBAs as substitute for the highly toxic AsH3 in MOVPE.