  Sequential infiltration synthesis (SIS) provides an original strategy to grow
inorganic materials by infiltrating gaseous precursors in polymeric films.
Combined with micro-phase separated nanostructures resulting from block
copoly-mer (BCP) self-assembly, SIS selectively binds the precursors to only
one domain mimicking the morphology of the original BCP template. This
methodology represents a smart solution for the fabrication of inorganic
nanostructures starting from self-assembled BCP thin films, in view of advanced
lithographic application and of functional nanostructure synthesis. The SIS
process using Trimethylaluminum (TMA) and H2O precursors in self-assembled
PS-b-PMMA BCP thin films established as a model system, where the PMMA phase is
selectively infiltrated. However the temperature range allowed by polymeric
material restricts the available precursors to highly reactive reagents, such
as TMA. In order to extend the SIS methodology and access a wide library of
materials, a crucial step is the implementation of processes using reactive
reagents that are fully compatible with the initial polymeric template. This
work reports a comprehensive morphological (SEM, SE, AFM) and physico-chemical
(XPS) investigation of alumina nanostructures synthesized by means of a SIS
process using O3 as oxygen precursor in self-assembled PS-b-PMMA thin films
with lamellar morphology. The comparison with the H2O-based SIS pro-cess
validates the possibility to use O3 as oxygen precursor expanding the possible
range of precursors for the fabrication of inorganic nanostructures.
