Scanning tunneling microscopy observation of ultrathin epitaxial CoSi2(111) films grown at a high temperature

作者：Alekseev A A^*; Olyanich D A; Utas T V; Kotlyar V G; Zotov A V; Saranin A A

来源：Technical Physics, 2015, 60(10): 1508-1514.

DOI：10.1134/S1063784215100023

Scanning tunneling microscopy (STM) is used to study the basic laws of growth of ultrathin epitaxial CoSi2(111) films with Co coverages up to 4 ML formed upon sequential deposition of Co and Si atoms taken in a stoichiometric ratio onto the Co-Si(111) surface at room temperature and subsequent annealing at 600-700A degrees C. When the coverage of Co atoms is lower than similar to 2.7 ML, flat CoSi2 islands up to similar to 3 nm high with surface structure 2 x 2 or 1 x 1 grow. It is shown that continuous epitaxial CoSi2 films containing 3-4 triple Si-Co-Si layers grow provided precise control of deposition. CoSi2 films can contain inclusions of the local regions with (2 x 1)Si reconstruction. At a temperature above 700A degrees C, a multilevel CoSi2 film with pinholes grows because of vertical growth caused by the difference between the free energies of the CoSi2(111) and Si(111) surfaces. According to theoretical calculations, structures of A or B type with a coordination number of 8 of Co atoms are most favorable for the CoSi2(111)2 x 2 interface.

• 出版日期2015-10