Kolobov A.V.,Nanoelectronics Research Institute |
Fons P.,Nanoelectronics Research Institute |
Krbal M.,Nanoelectronics Research Institute |
Tominaga J.,Nanoelectronics Research Institute
Physica Status Solidi (A) Applications and Materials Science | Year: 2012
The structure of the amorphous phase of GeTe-based phase-change materials is discussed. Comparison of the Ge(4):Te(2) and Ge(3):Te(3) configurations present in the amorphous phase suggests that the former is locally more stable while the latter can lower its energy due to 'resonance' interactions in structures within more extended order. We further demonstrate that polyvalency of the Ge-Te bonds can lead to the formation of negative-U defects accounting for the high resistivity of the amorphous phase. Finally, polyamorphysm of the amorphous phase of Ge 2Sb 2Te 5 is discussed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Morita Y.,Nanoelectronics Research Institute |
Migita S.,Nanoelectronics Research Institute |
Mizubayashi W.,Nanoelectronics Research Institute |
Masahara M.,Nanoelectronics Research Institute |
Ota H.,Nanoelectronics Research Institute
Solid-State Electronics | Year: 2013
Ultrathin HfO2 gate stacks with very high permittivity were fabricated by atomic layer deposition (ALD) and a novel two-step post-deposition annealing (PDA) technique. First, a no-cap pre-crystallization anneal degasses residual contaminations in the ALD layer, and second, a Ti-cap anneal enhances the permittivity of HfO2 by generating a cubic crystal phase. The Ti-cap layer simultaneously suppresses growth of interfacial SiO2 during annealing by absorbing residual oxygen released from HfO2. Using these techniques, the dielectric constant of the ALD-HfO2 could be enhanced to 40 for 2.4-4.0 nm HfO2 thickness. © 2013 Elsevier Ltd.
Ando K.,Nanoelectronics Research Institute
AIST Today (International Edition) | Year: 2010
Spintronics is a new electronics technology using nanometer-scale magnets that is expected to play a significant role in improving the energy efficiency of computers. The greatest advantage of electronic devices employing magnets is their ability to store information without using energy (non-volatile memory). This technology allows magnetism and electricity to be connected at the quantum mechanics level. The next target of spintronics technology is to develop a non-volatile computer memory. If the memory is made non-volatile, the power of the computer can be completely turned off at short intervals without the user even being aware of it. Such a computer would not need a power switch. Toshiba, Osaka University, Tohoku University, and the University of Electro- Communications have collaborated to develop a large-capacity spin-RAM, which enables more than 1 Gbit RAM.