Interconnection technology is a key factor in the continual advancement of integrated systems. The rapid increase in device density and circuit complexity through scaling demands a similar increase in the interconnection density. Traditionally, this is achieved by reducing the metal pitch as well as gradually increasing the number of interconnection levels. As the width and spacing of interconnections are scaled down to submicron dimensions at the chip level and micron dimensions at the board level, signal delay, crosstalk, electromigration, and stress-induced migration become important concerns.Cu holds promise as an alternative metallization material to Al alloy due to its low resistivity and ability to reliably carry high-current densities. Cu has a bulk resistivity of 1.68 μΩ-cm, whereas Al has a bulk resistivity of 2.65 μΩ-cm. The only metal with a resistivity lower than Cu is Ag. Since Cu has a melting point and atomic weight both higher than Al, it is expected to have better resistance to electromigration, although properties such as grain structure and resistance to corrosion at high temperatures may also affect electromigration characteristics.
We fabricated metal-insulator-metal (MIM) thin film capacitors with Bi1.5Zn1.0Nb1.5O7 (BZN) dielectric films. The BZN films were deposited at room temperatures by pulsed laser deposition and annealed below 200°C which is compatible with the used polymer-based substrates. The dielectric constant of BZN films increases from 2 to 70, when they are annealed at 150°C, but still in amorphous phase. We found that a considerable portion of Bi metallic phase still remains in the as-deposited film. They turn into oxides upon annealing at >120°C, causing the dramatic change of the dielectric properties. Amorphous BZN thin films exhibit superior dielectric characteristics, capacitance density of 150nF∕cm2, and leakage current less than 1μA∕cm2 at 5V. The MIM capacitors using amorphous BZN thin films will be a promising candidate for the PCB-embedded capacitors.
Multiscale and multimodal
imaging of material structures and properties
provides solid ground on which materials theory and design can flourish.
Recently, KAIST announced 10 flagship research fields, which include
KAIST Materials Revolution: Materials and Molecular Modeling, Imaging,
Informatics and Integration (M3I3). The M3I3 initiative aims to reduce
the time for the discovery, design and development of materials based
on elucidating multiscale processing–structure–property
relationship and materials hierarchy, which are to be quantified and
understood through a combination of machine learning and scientific
insights. In this review, we begin by introducing recent progress
on related initiatives around the globe, such as the Materials Genome
Initiative (U.S.), Materials Informatics (U.S.), the Materials Project
(U.S.), the Open Quantum Materials Database (U.S.), Materials Research
by Information Integration Initiative (Japan), Novel Materials Discovery
(E.U.), the NOMAD repository (E.U.), Materials Scientific Data Sharing
Network (China), Vom Materials Zur Innovation (Germany), and Creative
Materials Discovery (Korea), and discuss the role of multiscale materials
and molecular imaging combined with machine learning in realizing
the vision of M3I3. Specifically, microscopies using photons, electrons,
and physical probes will be revisited with a focus on the multiscale
structural hierarchy, as well as structure–property relationships.
Additionally, data mining from the literature combined with machine
learning will be shown to be more efficient in finding the future
direction of materials structures with improved properties than the
classical approach. Examples of materials for applications in energy
and information will be reviewed and discussed. A case study on the
development of a Ni–Co–Mn cathode materials illustrates
M3I3’s approach to creating libraries of multiscale structure–property–processing
relationships. We end with a future outlook toward recent developments
in the field of M3I3.
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