Homoepitaxial growth of α-Al₂O₃ thin films on atomically stepped sapphire substrates by pulsed laser deposition at room-temperature

Abstract

Influence of the atomic-scale surface morphology of sapphire substrates on the epitaxial growth and crystallinity of Al₂O₃ thin films was investigated by pulsed laser deposition (PLD) toward sapphire substrate engineering. Homoepitaxial growth of α-Al₂O₃ thin films on R-plane sapphire (0112) substrates with 0.35-nm-high atomic steps and approximately 20-nm-wide terraces was achieved at room-temperature (approximately 20°C) by PLD. Epitaxial growth of the α-Al₂O₃ thin films was confirmed by in situ reflection high-energy electron diffraction (RHEED). The obtained epitaxial film surface was atomically stepped similar to the sapphire substrate before deposition.