Characteristics of Gd2− x La x O3 high-k films by metal-organic chemical vapor deposition

Abstract: Gd2− x La x O3 high-k films were deposited on (100) 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 Gd2− x La x O3 films have been investigated. X-ray diffraction patterns show that as-deposited thick Gd2− x La x O3 films on Si have formed cubic phase of solid solution with (222) preferred orientation. The band gap of the Gd2− x La x O3 films can be calculated to be 5.78eV 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 1.08nm has been obtained with the flatband voltage (V fb) of 1.0V and leakage current density (J A) of 3A/cm2 at V g = V fb +1V for Gd2− x La x O3 (x =1.29) films of 8nm physical thickness after 800°C post-annealing. [Copyright &y& Elsevier]