46 research outputs found
Giant Electroresistance in Edge Metal-Insulator-Metal Tunnel Junctions Induced by Ferroelectric Fringe Fields
An enormous amount of research activities has been devoted to developing new types of non-volatile memory devices as the potential replacements of current flash memory devices. Theoretical device modeling was performed to demonstrate that a huge change of tunnel resistance in an Edge Metal-Insulator-Metal (EMIM) junction of metal crossbar structure can be induced by the modulation of electric fringe field, associated with the polarization reversal of an underlying ferroelectric layer. It is demonstrated that single three-terminal EMIM/Ferroelectric structure could form an active memory cell without any additional selection devices. This new structure can open up a way of fabricating all-thin-film-based, high-density, high-speed, and low-power non-volatile memory devices that are stackable to realize 3D memory architectureope
Nonvolatile ferroelectric control of ferromagnetism in (Ga,Mn)As
There is currently much interest in materials and structures that provide
coupled ferroelectric and ferromagnetic responses, with a long-term goal of
developing new memories and spintronic logic elements. Within the field there
is a focus on composites coupled by magnetostrictive and piezoelectric strain
transmitted across ferromagnetic-ferroelectric interfaces, but substrate
clamping limits the response in the supported multilayer configuration favoured
for devices. This constraint is avoided in a ferroelectric-ferromagnetic
bilayer in which the magnetic response is modulated by the electric field of
the poled ferroelectric. Here, we report the realization of such a device using
a diluted magnetic semiconductor (DMS) channel and a polymer ferroelectric
gate. Polarization reversal of the gate by a single voltage pulse results in a
persistent modulation of the Curie temperature as large as 5%. The device
demonstrates direct and quantitatively understood electric-fieldmediated
coupling in a multiferroic bilayer and may provide new routes to nanostructured
DMS materials and devices via ferroelectric domain nanopatterning. The
successful implementation of a polymer-ferroelectric gate fieldeffect
transistor (FeFET) with a DMS channel adds a new functionality to semiconductor
spintronics and may be of importance for future low-voltage spintronics devices
and memory structures.Comment: 19 pages, 5 figure
Active layers of high-performance lead zirconate titanate at temperatures compatible with silicon nano- and microelecronic devices
Applications of ferroelectric materials in modern microelectronics will be greatly encouraged if the
thermal incompatibility between inorganic ferroelectrics and semiconductor devices is overcome.
Here, solution-processable layers of the most commercial ferroelectric compound ─ morphotrophic
phase boundary lead zirconate titanate, namely Pb(Zr0.52Ti0.48)O3 (PZT) ─ are grown on silicon
substrates at temperatures well below the standard CMOS process of semiconductor technology.
The method, potentially transferable to a broader range of Zr:Ti ratios, is based on the addition of
crystalline nanoseeds to photosensitive solutions of PZT resulting in perovskite crystallization from
only 350 °C after the enhanced decomposition of metal precursors in the films by UV irradiation. A
remanent polarization of 10.0 μC cm−2 is obtained for these films that is in the order of the switching
charge densities demanded for FeRAM devices. Also, a dielectric constant of ~90 is measured at
zero voltage which exceeds that of current single-oxide candidates for capacitance applications. The
multifunctionality of the films is additionally demonstrated by their pyroelectric and piezoelectric
performance. The potential integration of PZT layers at such low fabrication temperatures may redefine
the concept design of classical microelectronic devices, besides allowing inorganic ferroelectrics to
enter the scene of the emerging large-area, flexible electronics
An organic field-effect transistor with programmable polarity
Selective ambipolar transport in solution-processed polymer ferroelectric field-effect transistors (FeFETs) is reported. Depending on the polarization state of the ferroelectric, either remanent hole or electron accumulation is achieved in the transistor, as illustrated by a butterfly-shaped current-voltage (I-V) transfer curve (see Figure). For memory purposes, the polarity of the channel can be easily read using the change in drain current in response to a small gate voltage
High-performance solution-processed polymer ferroelectric field-effect transistors
We demonstrate a rewritable, non-volatile memory device with flexible plastic active layers deposited from solution. The memory device is a ferroelectric field-effect transistor (FeFET) made with a ferroelectric fluoropolymer and a bisalkoxy-substituted poly(p-phenylene vinylene) semiconductor material. The on- and off-state drain currents differ by several orders of magnitude, and have a long retention time, a high programming cycle endurance and short programming time. The remanent semiconductor surface charge density in the on- state has a high value of 18 mC m(-2), which explains the large on/off ratio. Application of a moderate gate field raises the surface charge to 26 mC m(-2), which is of a magnitude that is very difficult to obtain with conventional FETs because they are limited by dielectric breakdown of the gate insulator. In this way, the present ferroelectric-semiconductor interface extends the attainable field-effect band bending in organic semiconductors