Structural transitions on Si(111) surface during Sn adsorption, electromigration, and desorption studied by in situ UHV REM

• Published in: Applied surface science Vol. 609; p. 155367
• Main Authors: Petrov, A.S., Rogilo, D.I., Zhachuk, R.A., Vergules, A.I., Sheglov, D.V., Latyshev, A.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 30.01.2023
• Subjects: Desorption; Electromigration; Silicon; Structural transitions; Surface; Tin; Electromigration; Tin; Silicon; Desorption; Surface; Structural transitions
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.155367

[Display omitted] •Sn-induced structural transitions on Si(111) at 200–860 °C have been first visualized.•γ-√3-Sn reconstruction formation atT > 650 °C induces step shift.•Sn surface electromigration entails √3-Sn⇔“1 × 1”-Sn phase transitions.•Sn adatoms have a positive effective charge being ≥ 0.001∙e.•Activation energy of Sn atom desorption from “1 × 1”-Sn layer is 2.5 ± 0.1 eV. Using in situ ultrahigh vacuum reflection electron microscopy, we have studied structural transitions on the Si(111) surface induced by Sn deposition up to 2 ML coverage (1 ML = 7.8∙1014 cm−2) and by Sn desorption at substrate temperatures T = 200–860 °C. We have shown that Si–Sn intermixing in the adsorption layer during Sn deposition onto the Si(111)-(7 × 7) surface at T > 650 °C leads to the shift of the monatomic steps in the step-up direction, and there is formed a mosaic (√3×√3)-Sn phase. The electromigration of Sn adatoms induced by DC resistive heating has been shown to redistribute adsorbed Sn layer and to cause local (√3×√3)-Sn ⇔ “1 × 1”-Sn structural transitions on the surface. We have estimated the lower bound of the Sn adatom positive effective charge on the Si(111) surface qeffSn ≥ 0.001∙e. During AC annealing, the rate of desorption-induced “1 × 1”-Sn domain area shrinkage has been measured as a function of substrate temperature, and the activation energy of Sn adatom desorption has been estimated to be 2.5 ± 0.1 eV.