The mechanisms of molecular beam epitaxy were investigated by growing and analyzing the shapes of facet structures which consisted of an (001) top surface and two (111)B side surfaces. It was found that all of the Ga flux on the 3 facet planes was incorporated into the film, but the growth rates on (111)B and (001) depended strongly upon the As flux and were governed mainly by the diffusion of Ga adatoms between the 2 planes. On the other hand, the diffusion of Al was found to be almost negligible; regardless of the As flux. By analyzing the shape of the facet, the diffusion length of Ga on a (001) surface was estimated to be about 1 at 580C, while that of Al was about 0.02. On (111)B, the diffusion length of Ga was found to be equal to several . The reflectivity of diffusing Ga atoms was found to be far less than unity for the (001)/(111)B boundary, and was almost equal to unity at facet boundaries where the (111)B side surfaces were bounded by the (1¯10) side walls.

S.Koshiba, Y.Nakamura, M.Tsuchiya, H.Noge, H.Kano, Y.Nagamune, T.Noda, H.Sakaki: Journal of Applied Physics, 1994, 76[7], 4138-44