In
this research, we report the rapid and reliable formation of
high-performance nanoscale bilayer oxide dielectrics on silicon substrates
via low-temperature deep ultraviolet (DUV) photoactivation. The optical
analysis of sol–gel aluminum oxide films prepared at various
concentrations reveals the processable film thickness with DUV photoactivation
and its possible generalization to the formation of various metal
oxide films on silicon substrates. The physicochemical and electrical
characterizations confirm that DUV photoactivation accelerates the
efficient formation of a highly dense aluminum oxide and aluminum
silicate bilayer (17 nm) on heavily doped silicon at 150 °C within
5 min owing to the efficient thermal conduction on silicon, resulting
in excellent dielectric properties in terms of low leakage current
(∼10–8 A/cm2 at 1.0 MV/cm) and
high areal capacitance (∼0.4 μF/cm2 at 100
kHz) with narrow statistical distributions. Additionally, the sol–gel
bilayer oxide dielectrics are successfully combined with a sol–gel
indium–gallium–zinc oxide semiconductor via two successive
DUV photoactivation cycles, leading to the efficient fabrication of
solution-processed oxide thin-film transistors on silicon substrates
with an operational voltage below 0.5 V. We expect that in combination
with large-area printing, the bilayer oxide dielectrics are beneficial
for large-area solution-based oxide electronics on silicon substrates,
while DUV photoactivation can be applied to various types of solution-processed
functional metal oxides such as phase-transition memories, ferroelectrics,
photocatalysts, charge-transporting interlayers and passivation layers,
etc. on silicon substrates.