  Superconductor-semiconductor nanowire hybrid structures are useful in
fabricating devices for quantum information processing. While selective area
growth (SAG) offers the flexibility to grow semiconductor nanowires in
arbitrary geometries, in-situ evaporation of superconductors ensures pristine
superconductor-semiconductor interfaces, resulting in strong induced
superconductivity in the semiconducting nanowire. In this work, we evaporated
islands of superconductor tin on InAs SAG nanowires, by using in-situ shadowing
with high aspect-ratio pre-fabricated SiOx dielectric walls. Our technique
allows complete customization of each physical parameter of such hybrid
nanostructures, while performing the nanowire and superconductor growths
without breaking vacuum. Using this technique, we grew
super(S)-normal(N)-super(S) (SNS), NS and SNSNS junctions. We performed
cryogenic electron transport measurements revealing the presence of gate and
field tunable supercurrents in shadow junctions fabricated on in-plane SAG
nanowires. We further measured the superconducting gap and critical fields in
the hybrid nanostructures and the crossover from 2e to 1e periodicity in the
SNSNS junctions, as a proof of the usability of these hybrid nanostructures.
