am7b12462_si_001.pdf (1.04 MB)
Nonuniform Composition Profiles in Amorphous Multimetal Oxide Thin Films Deposited from Aqueous Solution
journal contribution
posted on 2017-09-29, 00:00 authored by Keenan N. Woods, Milana C. Thomas, Gavin Mitchson, Jeffrey Ditto, Can Xu, Donna Kayal, Kathleen C. Frisella, Torgny Gustafsson, Eric Garfunkel, Yves J. Chabal, David C. Johnson, Catherine J. PageMetal oxide thin
films are ubiquitous in technological applications. Often, multiple
metal components are used to achieve desired film properties for specific
functions. Solution deposition offers an attractive route for producing
these multimetal oxides because it allows for careful control of film
composition through the manipulation of precursor stoichiometry. Although
it has been generally assumed that homogeneous precursor solutions
yield homogeneous thin films, we recently reported evidence of nonuniform
electron density profiles in aqueous-deposited films. Herein, we show
that nonuniform electron densities in lanthanum zirconium oxide (LZO)
thin films are the result of inhomogeneous distributions of metal
components. Specifically, La aggregates at the film surface, whereas
Zr is relatively evenly distributed throughout single-layer films.
This inhomogeneous metal distribution persists in stacked multilayer
films, resulting in La-rich interfaces between the sequentially deposited
layers. Testing of metal–insulator–semiconductor devices
fabricated from single and multilayer LZO films shows that multilayer
films have higher dielectric constants, indicating that La-rich interfaces
in multilayer films do not detrimentally impact film properties. We
attribute the enhanced dielectric properties of multilayer films to
greater condensation and densification relative to single-layer films,
and these results suggest that multilayer films may be preferred for
device applications despite the presence of layering artifacts.