Nanometer-thin film enables highest permittivity capacitors
Led by Dr. Minoru Osada and Principal Investigator Dr. Takayoshi Sasaki of the International Center for Materials Nanoarchitectonics (MANA) at the National Institute for Material Science (NIMS) in Japan, the research on good insulating, high-k nanofilms is expected to be key to future electronic applications. Minoru Osada and his colleagues created thin films based on titanium-niobate nanosheets (TiNbO5, Ti2NbO7, Ti5NbO14) as building blocks. The research group delaminated layered oxides and stacked sheets on an atomically flat SrRuO3 substrate, creating films between 5 and 15nm thick. The thin-film capacitors developed by this method have excellent dielectric characteristics, achieving a permittivity of 160 to 300) with a film thickness of 5 to 15nm.
The researchers relate the dielectric performance of the nanofilms to the structural features. In these nanosheets, the octahedral distortion inherent to site engineering by Nb doping results in a giant molecular polarizability.
This latest research demonstrates simultaneous improvements in a number of material properties, including relative permittivity, lower loss and leakage current. The authors add, "The solution-based room-temperature process using oxide nanosheets as building blocks opens multiple possibilities for the development of high-k dielectrics in capacitor technology, gate insulators in organic field effect transistors, energy-storage devices, and also future flexible electronics."
Tailor-made dielectric nanosheet via controlled nanoscale doping. (a) Structural change induced by Nb. (b) AFM image of titanium-niobate nanosheet. Source International Center for Materials Nanoarchitectonics.
Visit the International Center for Materials Nanoarchitectonics (MANA) at www.nims.go.jp/mana/index.html
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