Impurity incorporation during epitaxial growth of GaAs by chemical reaction

Vapour-phase epitaxy of GaAs in conditions where the growth is limited by t he chemical reactions of the gases with the substrate and not by gas transp ort is correctly understood in case the gases are produced by the decomposi tion of a GaAs source by H2O. Using secondary ion mass spectroscopy we have measured the efficiency at which various impurities (C, O, Si, S, Zn, Mg, Cr and Fe) are transported from the source into the grown layer. It is foun d that impurity transport is driven by the formation of volatile oxides, al lowing to foresee which impurity can or cannot be incorporated into the gro wn layer. (C) 2000 Elsevier Science B.V. All rights reserved.