Fabrication of Sr silicate buffer layer on Si(100) substrate by pulsed laser deposition using a SrO target

Abstract

The authors fabricated 2 × 1 Sr-reconstructed Si(100) substrates using thin SrO layers, and used them to direct growth of crystalline perovskite oxide on Si. The SrO layers used to reconstruct the Si(100) substrates were grown by pulsed laser deposition from a SrO single crystal target, followed by postdeposition-annealing (PDA) of the SrO/Si(100) structure. In situ observations of reflective high-energy electron diffraction during PDA confirmed a 2 × 1 reconstruction of the Si surface and x-ray photoemission spectroscopy of the annealed samples confirmed the existence of Sr atoms in a silicate phase, which indicated that a 2 × 1 Sr-reconstructed Si surface was achieved. The optimal fabrication conditions were annealing at 720 °C for 1 min and an equivalent SrO layer thickness (MLeq) of 2.5 MLeq. The temperature condition was very narrow, at 720 ± 20 °C, for an acceptable product. Subsequently, the authors demonstrated the growth of crystalline SrTiO3 films on the 2 × 1 Sr-reconstructed Si(100) surfaces.