Characteristics of Gd2−xLaxO3 high-k films by metal-organic chemical vapor deposition

Abstract

Gd 2− x La x O 3 high- k films were deposited on (1 0 0) Si substrates by low-pressure metal-organic chemical vapor deposition (MOCVD). The metal-organic precursors we used were Gd and La β-diketonates. The structure, band gap, composition and electrical properties of Gd 2− x La x O 3 films have been investigated. X-ray diffraction patterns show that as-deposited thick Gd 2− x La x O 3 films on Si have formed cubic phase of solid solution with (2 2 2) preferred orientation. The band gap of the Gd 2− x La x O 3 films can be calculated to be 5.78 eV using a UV–vis–NIR spectrophotometer. X-ray photoelectron spectroscopy depth profile analyses reveal that there exists an interfacial layer of Gd–La–Si–O silicate and the La element is rich in interfacial layer. The equivalent oxide thickness (EOT) of 1.08 nm has been obtained with the flatband voltage ( V fb ) of 1.0 V and leakage current density ( J A ) of 3 A/cm 2 at V g = V fb + 1 V for Gd 2− x La x O 3 ( x = 1.29) films of 8 nm physical thickness after 800 °C post-annealing. ► Gd 2− x La x O 3 high- k films were deposited on Si substrates by MOCVD. ► The structure, band gap, composition and electrical properties of Gd 2− x La x O 3 films have been investigated. ► The films have formed cubic phase of solid solution with (2 2 2) preferred orientation. ► Interfacial layer of the films is Gd–La–Si–O silicate and the La element is rich in interfacial layer. ► The EOT value of 1.08 nm is achieved. Gd 2− x La x O 3 high- k films were deposited on (1 0 0) Si substrates by low-pressure metal-organic chemical vapor deposition (MOCVD). The metal-organic precursors we used were Gd and La β-diketonates. The structure, band gap, composition and electrical properties of Gd 2− x La x O 3 films have been investigated. X-ray diffraction patterns show that as-deposited thick Gd 2− x La x O 3 films on Si have formed cubic phase of solid solution with (2 2 2) preferred orientation. The band gap of the Gd 2− x La x O 3 films can be calculated to be 5.78 eV using a UV–vis–NIR spectrophotometer. X-ray photoelectron spectroscopy depth profile analyses reveal that there exists an interfacial layer of Gd–La–Si–O silicate and the La element is rich in interfacial layer. The equivalent oxide thickness (EOT) of 1.08 nm has been obtained with the flatband voltage ( V fb ) of 1.0 V and leakage current density ( J A ) of 3A/cm 2 at V g = V fb + 1 V for Gd 2− x La x O 3 ( x = 1.29) films of 8 nm physical thickness after 800 °C post-annealing.