HEAVILY CARBON-DOPED GAAS GROWN ON VARIOUS ORIENTED GAAS SUBSTRATES BY MOMBE

Heavily carbon-doped GaAs epitaxial layers have been grown simultaneou sly on (100), (111)A, (111)B, (411)A, (411)B and (711)A semi-insulatin g (SI) GaAs substrates by metalorganic molecular beam epitaxy (MOMBE) using trimethylgallium (TMG) and elemental As (As-4). The hole concent ration and surface flatness strongly depend on the substrate orientati on. The highest carbon incorporation was observed for the layers grown on a (411)A substrate with a hole concentration of 1.0 x 10(21) cm(-3 ) and a lattice mismatch of Delta d/d = -0.48%. Atomic force microscop e (AFM) images reveal that the epilayers grown on (411)A substrates ex hibit extremely flat surfaces, although these layers contain the highe st carbon concentration.