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, Θ_Sb, during the initial Si MBE growth were evaluated as a function of the substrate temperature T_s. The temperature dependence of k, and Θ_Sb suggests that the Sb surface segregation kinetics are divided into three temperature regions: (I) T_s < ∼500°C, (II) ∼500°C < T_s < ∼700°C and (III) ∼700°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.