SUBSTITUTED ARSINES AS AS SOURCES IN MOMBE

We have for the first time used in the MOMBE (metal organic molecular beam epitaxy) of GaAs gaseous arsenic sources which do not require precracking in the gas inlet tube. The partially substituted arsines tBAsH2 and PhAsH2 decompose on the hot substrate surface and thus allow GaAs deposition. Using TEG as the Ga source layers grown from PhAsH2 were weakly p-type (4×1015cm-3) and showed narrow excitonic transitions in the low temperature photoluminescence spectrum. For both PhAsH2 and tBAsH2 we could not determine the occurrence of intrinsic (e.g. carbon) impurity uptake on a level much higher than that achieved with AsH3. However, the extrinsic purity of these starting materials needs further improvement. Whereas growth from uncracked tBAsH2 and PhAsH2 is possible, the trialkyl TMAs, similar to AsH3, is too stable to be used without precracking. © 1990.