Composition-dependent structural and electrical properties of Zr _xTiy O₂films grown on Ru O₂ substrate by ALD

We have investigated the structural and electrical properties of Zrx Tiy O2 films grown on a Ru O2 substrate by atomic layer deposition (ALD) with a variation of the ALD cycle ratio of Zr O2 [Zr O2 +Ti O2], RZr [Zr+Ti]. Ti O2 films (15 nm thick) grown at 225°C using water as an oxygen source showed a rutile structure and a dielectric constant of 90 after postannealing at 600°C. With an increase of RZr [Zr+Ti] to 0.50, the leakage current density of 15 nm thick Zrx Tiy O2 films grown at 225°C was improved to be 1.2× 10-6 A cm2, but the dielectric constant decreased to 20. This is attributed to the destruction of rutile Ti O2 structures into amorphous Zrx Tiy O2 phase by the increase of Zr content.