RHEED-AES observation of Sb surface segregation during Sb-mediated Si MBE on Si(0 0 1)

The Sb surface segregation during Si molecular beam epitaxy (MBE) on a Sb-saturated Si(0 0 1) surface has been investigated by the simultaneous usage of reflection high-energy electron diffraction and Auger electron spectroscopy (RHEED-AES). From a quantitative analysis of Sb MNN Auger electron spectra as excited by a grazing-incidence electron beam for RHEED, the Sb bulk incorporation rate, k, and the Sb surface coverage, Theta(Sb), during the initial Si MBE growth were evaluated as a function of the substrate temperature T-s. The temperature dependence of k, and Theta(Sb) suggests that the Sb surface segregation kinetics are divided into three temperature regions: (I) T-s < similar to 500 degrees C, (II) similar to 500 degrees C < T-s < similar to 700 degrees C and (III) similar to 700 degrees C < T-s. k decreases with increase in T-s in region I whereas k increases with T-s in region II. k also shows long-time-scale decrease with growth time for the regions I and II. These findings are explained in terms of Sb diffusion through MBE Si layers and the crystallinity of the MBE Si layers. (C) 1998 Elsevier Science B.V. All rights reserved.