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Ultrathin capacitor (from 34) “It’s fun to think that we can take these
classic materials that we thought we knew
Historically, synthesis attempts have re- everything about, and flip them on their
sulted in films that contain higher concen- head with new approaches to making and
trations of “defects” — points where the characterizing them,” said Martin.
structure differs from an idealized version
of the material — as compared to bulk Finally, by placing a film of BaTiO3 in be-
versions. tween two metal layers, Martin and his
team created tiny capacitors — the elec-
Approach limits defects tronic components that rapidly store and
Such a high concentration of defects nega- release energy in a circuit.
tively impacts the performance of thin
films. Martin and colleagues developed an
approach to growing the films that limits
those defects. The findings were published
in the journal Nature Materials.
To understand what it takes to produce
the best, low-defect BaTiO3 thin films,
the researchers turned to a process called
pulsed-laser deposition.
Firing a powerful beam of an ultraviolet
laser light onto a ceramic target of BaTiO3
causes the material to transform into a
plasma, which then transmits atoms from The research was carried out at Berkeley’s Molecular Foundry.
the target onto a surface to grow the film.
Faster performance
Versatile tool Applying voltages of 100 mV or less
“It’s a versatile tool where we can tweak and measuring the current that emerg-
a lot of knobs in the film’s growth and see es showed that the film’s polarization
which are most important for controlling switched within two billionths of a second
the properties,” said Martin. and could potentially be faster, competi-
tive with what it takes for today’s comput-
Martin and his colleagues showed that ers to access memory or perform calcula-
their method could achieve precise control tions.
over the deposited film’s structure, chem-
istry, thickness, and interfaces with metal Next, the team plans to shrink the mate-
electrodes. rial down even thinner to make it compat-
ible with real devices in computers and
By chopping each deposited sample in study how it behaves at those tiny dimen-
half and looking at its structure atom by sions.
atom using tools at the National Center for
Electron Microscopy at Berkeley Lab’s Mo- At the same time, they will work with
lecular Foundry, the researchers revealed collaborators at companies such as Intel
a version that precisely mimicked an ex- Corp. to test the feasibility in first-genera-
tremely thin slice of the bulk. tion electronic devices. lbl.gov
