In situ monitoring of atomic layer epitaxy via optical ellipsometry. (6th March 2018) - Lyzwa, F
Abstract: We report on the use of time-resolved optical ellipsometry to monitor the deposition of single atomic layers with subatomic sensitivity. Ruddlesden–Popper thin films of SrO(SrTiO3 ) n =4 were grown by means of metalorganic aerosol deposition in the atomic layer epitaxy mode on SrTiO3 (1 0 0), LSAT(1 0 0) and DyScO3 (1 1 0) substrates. The measured time dependences of ellipsometric angles, Δ( t ) and Ψ( t ), were described by using a simple optical model, considering the sequence of atomic layers SrO and TiO2 with corresponding bulk refractive indices. As a result, valuable online information on the atomic layer epitaxy process was obtained. Ex situ characterization techniques, i.e. transmission electron microscopy, x-ray diffraction and x-ray reflectometry verify the crystal structure and confirm the predictions of optical ellipsometry.