[21p-H113-1~18] 6.6 Probe Microscopy

△ [21p-H113-4] Identification of Si and Ge Atoms by Non-Contact Atomic Force Microscopy

〇(PC)Jo Onoda^1,2, Kouhei Niki², Yoshiaki Sugimoto^1,2 (1.Univ. Tokyo, 2.Osaka Univ.)

Keywords:atomic force microscopy,silicon,germanium

The intermixing can occur between the deposited Ge and the substrate Si atoms during the initial stage of the epitaxial growth of Ge on Si(111). Because of the similar chemical properties of Ge and Si, it has been severely difficult to discriminate Ge and Si adatoms on the intermixed Ge/Si(111)-(7×7) surfaces by scanning tunneling microscopy and non-contact atomic force microscopy (NC-AFM). We successfully identify individual Ge and Si atoms by analyzing histograms of maximum attractive forces in force spectroscopies. It is found that the more reactive tip we use the larger the separation of the peaks derived from Ge and Si are in the histograms. We demonstrate that the present method is also applicable to other reconstructed surfaces; Ge/Si(111)-(5×5). Although the adatoms in the topmost layer of Ge/Si(111)-(5×5) are dominantly occupied by Ge, a small amount of Si adatoms surely exist and are randomly distributed.