Carbon was effectively incorporated into AlAs between 1 x 10(18) and 8 x 10(20) cm(-3) using two different Al sources, taking advantage of atomic layer epitaxy (ALE). Based on the results of the X-ray diffraction measurement and secondary ion mass spectroscopy, we found that the lattice parameter of the AlAs epilayer was decreased with increasing carbon concentration [C], and therefore carbon could be substitutionally incorporated into AlAs. Hall measurements revealed that carbon acts as a p-type dopant in AlAs, and the obtained maximum hole concentration [p] is 3 x 10(19) cm(-3), which is the highest value ever reported for AlAs : C using the MOVPE system. Furthermore, numerical calculations together with experimental data suggested that AlAs:C layers can completely match the lattice parameters of GaAs when [C] = 3 x 10(20) cm-3, and also indicated that the electrical conductivity {[p] = 3 x 10(19) cm(-3)} in AlAs :C is sufficiently high enough to reduce the barrier height at the AlAs:C/GaAs interface.