Stress evolution during epitaxial growth of SrO films on hydrogen-terminated Si(111) surfaces

We use real-time measurement of substrate curvature to observe the film stress behavior during epitaxial growth of Sr metal films and their oxidation process at room temperature. The lattice mismatch stress and the thickness of strained layer are controlled to be minimized by using hydrogen-terminated Si whose surfaces have no active dangling bonds. The use of hydrogen-terminated Si(111) enables growth of stress-free Sr layers from a thickness of 1.05 nm, whereas the direct deposition films on Si(111) 7×7 have the strained layer with a thickness of 3.16 nm. We also observe that the intrinsic stress in the films changes drastically from compressive to tensile during the oxidation process resulting from the variation in lattice mismatch.