Synchrotron radiation X-ray reflectivity measurements were used to study the concentration profiles of δ-doped Er layers in Si epitaxial films which had been grown by means of molecular-beam epitaxy. Oscillation of the reflectivity amplitude as a function of reflection angle was monitored, and a theoretical simulation permitted the concentration profile of Er atoms to be derived. It was shown that the original δ-doped Er layer changed into an exponentially decaying function, due to Er segregation. The temperature dependence of the decay-length indicated that the segregation was a kinetically limited process with an activation energy of 0.044eV.

X-Ray Reflectivity Measurement of δ-Doped Erbium Profile in Silicon Molecular-Beam Epitaxial Layer J.Wan, Z.M.Jiang, D.W.Gong, Y.L.Fan, C.Sheng, X.Wan, Q.J.Jia, W.L.Zheng, X.M.Jiang: Physical Review B, 1999, 59[16], 10697-700