Acceptor doping of (Al,Ga)As using carbon by metalorganic vapor phase epitaxy

Carbon doping of AlxGa1-xAs with x = 0 to 0.3 has been investigated using trimethylarsine (TMAs) as the carbon precursor. Carbon concentrations from 5×1017 to {reversed tilde equals} 1020cm-3 have been achieved using AsH3/TMAs mixtures or TMAs alone. The carbon concentration increases with aluminum composition and decreasing AsH3/TMAs ratio. A contraction in the lattice constant is observed for carbon concentrations larger than {reversed tilde equals} 1018 cm-3 which is attributed to substitutional carbon. The carbon incorporation is non-uniform at higher carbon concentrations. The electrical activation of carbon in (Al,Ga)As is however, very low, of the order of 5%. © 1991.