Coordination and interface analysis of atomic-layer-deposition Al2O3 on Si(001) using energy-loss near-edge structures

Abstract

The coordination and interface of Al2O3 formed on Si(001) by atomic layer deposition (ALD) were studied using electron energy-loss spectroscopy in a transmission electron microscope. Al energy-loss near-edge structures (ELNESs) were interpreted using first-principles calculations. The Al L23 ELNESs show two peaks at 78.2 and 79.7 eV, which originate from tetrahedrally and octahedrally coordinated aluminum, respectively. The depth profile of coordination in ALD Al2O3/Si was investigated. While both tetrahedrally and octahedrally coordinated Al atoms exist in the ALD Al2O3, the former is dominant near the interface. Aluminum silicate was detected near the interface, and it may cause the difference in aluminum coordination.