Composition, atomic transport, and chemical stability of ZrAlxOy ultrathinfilms deposited on Si(001)

The stability of a ZrAlxOy film sputtered on Si upon thermal annealing in v acuum or in O-2 was investigated. X-ray diffraction indicated that the as-d eposited film was amorphous and remained so after annealing. Rutherford bac kscattering, narrow nuclear resonance profiling, and low-energy ion scatter ing provided the average composition of the film and the depth distribution s of different elements. Chemical analysis of these elements was accessed b y x-ray photoelectron spectroscopy. Annealing in vacuum produced thickness inhomogeneities and/or transport of very small amounts of Si from the subst rate into the overlying film, with formation of Si precipitates. Annealing in O-2 led to oxygen exchange throughout the film, as well as Si transport in slightly higher amounts than in vacuum. Differently from the observed up on annealing in vacuum, Si was either incorporated into the Zr,Al-O framewo rk or oxidized in SiO2. (C) 2001 American Institute of Physics.