OPTIMIZATION OF CARBON INCORPORATION IN GAAS DURING MOLECULAR-BEAM EPITAXIAL-GROWTH

Carbon-doped GaAs with dopant concentrations up to about 10(20) cm(-3) has been grown by molecular beam epitaxy. Above a critical carbon con centration, which depends on the deposition parameters, the surface de teriorates and loses its mirror-like appearance. From X-ray diffractom etry and scanning electron microscopy, a diagram is established separa ting two areas with rough and mirror-like surface morphologies. The el ectrical properties as well as the morphology of GaAs: C can be simult aneously improved by a careful adjustment of the deposition parameters according to this diagram.