The incorporation of more than 1019/cm3 of Si, Be, and C into relaxed InxGa1-xAs layers was studied, for x-values of up to 0.16, by Raman spectroscopy of the local vibrational modes. The frequencies of the Raman peaks, which resulted from the convolution of several split modes, shifted to lower values as the In content was increased. The CAs (C acceptor) local mode frequency exhibited the strongest dependence upon x. Features which could be attributed only to the effect of In upon second-nearest neighbor sites were identified only in Si-doped samples. The transverse and longitudinal modes, which were expected from the splitting of a local vibrational mode of CAs, with one In first-nearest neighbor, were not observed in layers with x-values of up to 0.085. It was concluded that In increased the total electrical activation of Si and favored its incorporation at group-III sub-lattice sites. On the other hand, no effect of In upon Be or C dopant activation was detected. An analysis of the CAs local vibrational mode spectra supported the view that CAs was preferentially surrounded by Ga, rather than In, atoms at x-values of up to 0.085.

A.L.Alvarez, F.Calle, A.Sacedón, E.Calleja, E.Muñoz, J.Wagner, M.Maier, A.Mazuelas, K.H.Ploog: Journal of Applied Physics, 1995, 78[7], 4690-5