Real-time stress/strain measurement during growth of Sr and SrO epilayer on H-terminated Si

Abstract

We use real-time measurement of substrate curvature and reflection high energy electron diffraction (RHEED) methods to observe the film stress/strain behavior during epitaxial growth of Sr metal films and their oxidation process. The film stress and the thickness of the strained layer are minimized by using hydrogen-terminated Si substrates. The use of hydrogen-terminated Si(111) enables the growth of stress-free Sr layers from a thickness of 1.05 nm, whereas the films directly deposited on Si(111) 7×7 shows the presence of a strained layer with a thickness of 3.16 nm. We also observed that the intrinsic stress in the films changes drastically from compressive to tensile during the oxidation process, resulting from the variation in lattice mismatch.