We have studied the growth process of the topological insulator (TI) Sb2Te3Sb2Te3 on Si(111) by scanning tunneling microscopy. High quality thin films from more than 22 nm down to 1 nm in thickness have been deposited by molecular beam epitaxy. To determine the thickness and domain formation of the films, x-ray reflectivity and x-ray diffraction were utilized. In comparison to previous studies of the TI Bi2Te3Bi2Te3, the growth mechanism of Sb2Te3Sb2Te3 shows a similar transition from nucleation and growth in Sb–Te and Te–Te bilayers, respectively, to mound formation for thicker films. Atom probe tomography measurements reveal a intermixed interface between Sb2Te3Sb2Te3 and Si(111) substrate. These findings can explain the high density of defects and domains.