LOW-OXYGEN AND CARBON INCORPORATION IN ALGAAS USING TRITERTIARYBUTYLALUMINUM IN ORGANOMETALLIC VAPOR-PHASE EPITAXY

High-quality AlGaAs epilayers have been grown by low pressure organome tallic vapor phase epitaxy with a new aluminum precursor tritertiarybu tylaluminum (TTBAl). Layers grown at 650 degrees C have a featureless mirror surface morphology and strong room temperature photoluminescenc e. Carbon was not detectable in chemical analysis by secondary ion mas s spectroscopy, nor in low temperature (4K) photoluminescence spectra. Oxygen concentration in Al0.25Ga0.75As is as low as similar to 2-3 x 10(17) cm(-3). Nominally undoped AlGaAs layers exhibit n-type conducti vity with electron concentrations at similar to 1-1.5 x 10(16) cm(-3). A high degree of compositional uniformity over 5 cm diam substrates ( 0.268 +/- 0.001) was obtained. These results indicate the potential fo r TTBAl as an aluminum precursor for low temperature growth of Al-cont aining III-V alloys.