Infrared spectroscopy and X-ray diffraction studies on the crystallographic evolution of La2O3 films upon annealing - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue Microelectronic Engineering Année : 2008

Infrared spectroscopy and X-ray diffraction studies on the crystallographic evolution of La2O3 films upon annealing

Résumé

Rare earth oxides (REOs) have lately received extensive attention in relation to the continuous scaling down of non-volatile memories (NVMs). In particular, La2O3 films are promising for integration into future NVMs because they are expected to crystallize above 400 °C in the hexagonal phase (h-La2O3) which has a higher κ value than the cubic phase (c-La2O3) in which most of REOs crystallize. In this work, La2O3 films are grown on Si by atomic layer deposition using La(C5H5)3 and H2O. Within the framework of the h-La2O3 formation, we systematically study the crystallographic evolution of La2O3 films versus annealing temperature (200–600 °C) by Fourier transform infrared spectroscopy (FTIR) and grazing incidence X-ray diffraction (GIXRD). As-grown films are chemically unstable in air since a rapid transformation into monoclinic LaO(OH) and hexagonal La(OH)3 occurs. Vacuum annealing of sufficiently thick (>100 nm) La(OH)3 layers induces clear changes in FTIR and GIXRD spectra: c-La2O3 gradually forms in the 300–500 °C range while annealing at 600 °C generates h-La2O3 which exhibits, as inferred from our electrical data, a desirable κ ∼ 27. A quick transformation from h-La2O3 into La(OH)3 occurs due to H2O absorption, indicating that the annealed films are chemically unstable. This study extends our recent work on the h-La2O3 formation.

Dates et versions

hal-01745039 , version 1 (27-03-2018)

Identifiants

Citer

D. Tsoutsou, G. Scarel, A. Debernardi, S. C. Capelli, S. N. Volkos, et al.. Infrared spectroscopy and X-ray diffraction studies on the crystallographic evolution of La2O3 films upon annealing. Microelectronic Engineering, 2008, 85 (12), pp.2411-2413. ⟨10.1016/j.mee.2008.09.033⟩. ⟨hal-01745039⟩
73 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More