This article presents a comprehensive study of the dependence of impurity incorporation on the crystallographic orientation during metalorganic vapor phase epitaxy of III-V compound semiconductors. We performed doping experiments for group-II impurities (Zn and Mg), group-VI impurities (Se and O), and a group-IV impurity (Si form SiH4 and Si2H6). The host materials were GaAs, Ga0.5In0.5P, and (Al0.7Ga0.3)0.5In0.5P grown on GaAs substrates. We examined the doping efficiency on the surfaces lying between {100} and {111}A/B. Even though we grew epitaxial layers in a mass-transport-limited regime, the doping efficiency significantly depended on the orientation, indicating that the surface kinetics plays an important role in impurity incorporation. Comparing our results with other reports, we found that acceptor impurities residing on the group-III sublattice and donor impurities residing on the group-V sublattice, respectively, have their own distinctive orientation dependence. Si donors exhibit orientation dependences which are either negligible or are similar to group-VI donors, depending on the growth conditions. We constructed a model for the orientation dependences, considering atomic bonding geometries between impurity adsorbates and adsorption sites.

Undoped GaSb crystals with mirror-like surfaces were obtained by liquid phase epitaxy from Sb-rich solutions. The background carrier concentration strongly depended on the growth temperature. By growing crystals below 600 °C, we can obtain a GaSb crystal with a background carrier concentration under 1016 cm−3. Photoluminescence studies showed that native defects related to Sb vacancies were significantly reduced in the GaSb crystal.

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A vapor-phase decomposition mechanism for the trimethylaluminum(TMA) used in an Al CVD was investigated by infrared spectroscopy. In pyrolysis, the annihilation of TMA was a first-order reaction and a CH3 radical was generated. The activation energy of the annihilation was about 0.4 eV. The generation mechanism of CH4 from the intermediates was investigated quantitatively. It is suggested that carbon contamination can be reduced by using an H2 carrier gas since the CH3 radical which causes such contamination is changed into CH4 by hydrogenation. In photolysis, the annihilation of TMA is a first-order reaction and C2H6 is generated by the coupling of two CH3 groups. The reduction of carbon contamination is also suggested because the generation of a CH3 radical is suppressed by the generation of C2H6.