Through the constant quest for miniaturization, transistors and all their components continue to decrease in size. A similar reduction has resulted in the thickness of a component material known as the gate dielectric – typically a thin layer of silicon dioxide, which has now been in use for decades. Unfortunately, as the thickness of the gate dielectric decreases, silicon dioxide begins to leak current, leading to unwieldy power consumption and reduced reliability. Scientists hope that this material can be replaced with others, known as high-dielectric constant (or high-k) dielectrics, which mitigate the leakage effects at these tiny scales.
Metal oxides with high-k have attracted tremendous interest due to their application as novel materials in the latest generation of devices. The impetus for their practical introduction would be further helped if their ability to capture and trap charges and subsequent impact on instability of device performance was better understood. It has long been believed that these charge-trapping properties originate from structural imperfections in materials themselves. However, as is theoretically demonstrated in this publication, even if the structure of the high k dielectric material is perfect, the charges (either electrons or the absence of electrons – known as holes) may experience ‘self trapping’. They do so by forming polarons – a polarizing interaction of an electron or hole with the perfect surrounding lattice. Professor Alexander Shluger of the London Centre for Nanotechnology and the Department of Physics & Astronomy at UCL says: “This creates an energy well which traps the charge, just like a deformation of a thin rubber film traps a billiard ball.”
The resulting prediction is that at low temperatures electrons and holes in these materials can move by hopping between trapping sites rather than propagating more conventionally as a wave. This can have important practical implications for the materials’ electrical properties. In summary, this new understanding of the polaron formation properties of the transition metal oxides may open the way to suppressing undesirable characteristics in these materials.
David Weston | alfa
New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship
Solar wind impacts on giant 'space hurricanes' may affect satellite safety
19.09.2017 | Embry-Riddle Aeronautical University
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...
Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.
Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
19.09.2017 | Event News
19.09.2017 | Physics and Astronomy
19.09.2017 | Power and Electrical Engineering