Dresden 2026 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
O: Fachverband Oberflächenphysik
O 28: Oxide and insulator surfaces: Structure, epitaxy and growth – Poster
O 28.2: Poster
Monday, March 9, 2026, 18:00–20:00, P2
Influence of sample temperature on electron-beam-induced modifications in ultrathin CaF2 films on Si(111) — •Luis Witte, Chris Schröder und Joachim Wollschläger — Institute of Physics, University of Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany
The development of modern transistor technologies based on 2D materials requires gate dielectrics with low defect densities and high chemical stability. CaF2 layers on Si(111) are well suited for this purpose due to their low lattice mismatch and large band gap. However, a crucial aspect is their stability under electron irradiation, e.g. during LEED analysis of the layers, which can lead to structural and chemical changes.
In this study, ultrathin CaF2 layers were deposited on Si(111) using molecular beam epitaxy. First, a growth temperature study was carried out at substrate temperatures between 400 ∘C and 700 ∘C. In a second step, the influence of the sample temperature during LEED measurements on the structural stability of the layers was studied. The electron beam of the LEED served both as a source of excitation for structural changes and as a probe for detecting these modifications. The measurements were conducted at sample temperatures from −150 ∘C to 600 ∘C in order to systematically investigate temperature-related effects. The results show that modifications induced by the electron beam exhibit a pronounced temperature dependence. In addition, ex-situ XPS measurements were performed to analyse chemical changes.
Keywords: Calcium fluoride; Si(111); MBE; LEED; XPS