A research group headed by MANA Scientist Dr. Minoru Osada and Principal
Investigator Dr. Takayoshi Sasaki of the International Center for
Materials Nanoarchitectonics (MANA) at the National Institute for
Materials Science (NIMS) discovered a new high-k dielectric nanosheet
with a molecular level thickness (∼1.5 nm), and successfully developed
the world's highest performance thin-film condenser by a solution-based
bottom-up nanotechnology.
Condensers
based on dielectric thin films are a key component of electronic
devices, where they perform essential functions such as storing
electrical charge, and blocking direct current while allowing
alternating currents to propagate. Because condensers are the largest
components in our electronic equipments such as cell phones, personal
computers, etc., extensive efforts are directed at the developments of
high performance condensers with smaller size and higher capacitance.
Central
to these researches is the design and integration of ultrathin high-k
dielectrics such as perovskite-structure BaTiO3 and (Ba1-xSrx)TiO3,
which should provide more capacitance per unit area of device. However,
current perovskite thin films yield reduced dielectric constants that
are one order of magnitudesmaller than bulk values. This so-called size
effect is a long-standing conundrum in perovskite dielectrics, which
limits further miniaturization and enhanced capacitance in condensers
devices.
This
research group conducted a search for new high-k nanodielectrics, and
discovered a moleculary thin high-k nanosheet (perovsikte nanosheet)
that afford robust high-k properties even at several nanometer
thicknesses, allowing high capacitances. By solution-based bottom-up
approach using perovskite nanosheets, the group successfully fabricated
thin-film condensers directly on SrRuO3 or Pt substrates with a clean
interface. These devices exhibited a high capacitance density (with
dielectric constant of 210 - 240), the largest value seen so far in
current perovskite films with the thickness down to 10 nm. This result
enables further miniaturization and enhanced capacitance in thin film
condensers, and opens a new route to the development of high performance
condenser devices desirable for future electronic equipments.
This
research was carried out as part of the research project "Development
of Nanomaterials/Manufacturing Processes for Next-generation Electronics
Using Inorganic Nanosheets" (Project Leader: Takayoshi Sasaki) in the
"Establishment of Innovative Manufacturing Technology Based on
Nanotechnology" Research Area ofthe Core Research of Evolutional Science
& Technology (CREST) Program of the Japan Science and Technology
Agency (JST). This result was published in the online edition of ACS
Nano on August 24.
More information at NIMSSOURCE: National Institute for Materials Science
