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The incorporation of both dopants and background impurities during the organometallic vapor phase epitaxial ͑OMVPE͒ growth of GaAs, GaInP, and GaP has been significantly altered by the use of the surfactants Sb and Bi. Sb and Bi are isoelectronic with the group V host elements, and so produce no independent doping. This paper demonstrates that the incorporation of Zn can be increased by an order of magnitude in GaP to a value of approximately 10 20 cm −3 , the highest value reported to date. Additionally, these same surfactants lead to significant decreases in carbon contamination during growth. At high growth temperatures the reduction can be as large as 100ϫ in GaP. The surfactants also result in marked decreases in autodoping due to S and Si from the substrate. A marker that may help identify the mechanism for these effects is H incorporation. Both Sb and Bi surfactants give rise to increased concentrations of H in the GaP layers. Similar effects are observed in GaInP. However, in GaAs, no H is detected in the layers. One possible explanation for these phenomena is that Sb or Bi increases the surface H concentration. The increased H would have two possible effects on the incorporation of dopants and impurities. ͑1͒ Passivation of the Zn acceptor by formation of a neutral Zn-H complex would lead to increased incorporation for thermodynamic reasons. ͑2͒ Allowing increased desorption of C, S, and Si from the surface by increased formation of volatile hydrides leads to decreased incorporation levels. These results suggest a simple and effective method of controlling the incorporation of dopant and impurity atoms by adding a minute amount of surfactant during OMVPE growth.

GaAs:N is an interesting material for many devices due to its unique compositional variation of band gap. Small amounts of N lead to a strong decrease in band gap energy as well as lattice constant. The further addition of In or Sb leads to quaternary alloys with band gap energies below 1.4 eV lattice matched to GaAs. One drawback of these alloys is the low solubility of N in GaAs. Some success has been obtained using low growth temperatures and V/III ratios during organometallic vapor phase epitaxy to kinetically limit phase separation. This article describes mechanisms for N incorporation into the GaAs crystal during growth and shows how surfactants like Sb, Bi, and Tl, as well as B, affect N incorporation. A decrease of the N content in GaAs was found for Sb, Bi, and Tl, which can be explained using a simple Langmuir model with competitive adsorption. The surface morphology of the epitaxial layers and the influence of surfactants was analyzed using atomic force microscopy.

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