Growth of In _x Ga _1−x As Films on GaAs (100): Inserting an Ultrathin In _x Ga _1−x As Buffer Using a Surface Technology

ABSTRACT The mechanism of the In‐catalyzed reaction of GaAs with In metal to form In x Ga 1−x As was explained by comparing the interfacial reactions of metallic In and GaAs at high and low temperatures. Specifically, GaAs dissolved in In metal at the defects under the catalysis of In, and then In diffused into the GaAs crystals to replace Ga in the lattices. Based on this mechanism, a new method was developed for preparing an In x Ga 1−x As buffer layer on GaAs by combining the ion‐sputtering method and annealing. The buffer layer and its effect on the quality of the epitaxial layer grown on GaAs were verified and analyzed by transmission electron microscopy, X‐ray diffraction, Hall effect measurements, and Raman scattering. The buffer layer was found to adopt the original dislocations on the GaAs surface, which prevented substrate dislocations from entering the epitaxial layer and reduced the dislocations generated due to the mismatch between the substrate and buffer layer. When the composition of the epitaxial layer is similar to that of the buffer layer, the quality of the epitaxial layer is significantly improved.