title: Thermal stability of HfO2-on-GaAs nanopatterns.
abstract: We have evaluated the effect of thermal annealing on the morphology, crystalline phase and elemental composition of high-k dielectric HfO(2)-on-GaAs nanopatterns at 500-620 °C by using atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS). While the HfO(2)-GaAs interface continues to be atomically abrupt at 620 °C, we have found a gradual shrinkage in the pattern linewidth and period with increasing temperature. Facet formation triggered by a nanoscale-modulated sequence of tensile and compressive stresses on the GaAs substrate, observed at 620 °C, has been attributed to a volumetric expansion of the HfO(2) nanostructures, caused by the tetragonal/cubic to monoclinic HfO(2) phase transformation and, to a lesser extent, by solid-state diffusion of As into HfO(2).
authors.affiliation: Instituto de Ciencia de Materiales de Madrid, CSIC, C/Sor Juana Inés de la Cruz 3, 28049-Madrid, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Galiana
authors.forename: Marcos
authors.initials: M
authors.lastname: Benedicto
authors.forename: Luis
authors.initials: L
authors.lastname: Vázquez
authors.forename: Jon M
authors.initials: JM
authors.lastname: Molina-Aldareguia
authors.forename: Paloma
authors.initials: P
authors.lastname: Tejedor