The perfect data storage solution should offer fast access to data, maintain data in the absence of external power, and be able to withstand large numbers of read–write cycles.
Phase-change random access memory (PCRAM), a type of non-volatile memory that uses the amorphous and crystalline states of phase-change materials for encoding data, can satisfy all of these criteria. Unfortunately, PCRAM also tends to have impractically high power requirements that have impeded its application in many devices. Desmond Loke and co-workers at the A*STAR Data Storage Institute have now demonstrated a technology that could help reduce the power requirements of PCRAM.
The high power requirements of PCRAM are a consequence of the high heat levels necessary to drive the transformation between the crystalline and amorphous phases. This heat in turn usually requires relatively large current pulses, which also makes it difficult to integrate with small transistors. Loke and co-workers designed their PCRAM to make the most of this generated heat by replacing the dielectric that surrounds the phase-change material with a material that also acts as a high-performance thermal insulator.
Most dielectric materials, such as silicon dioxide (SiO2) and aluminum oxide (Al2O3), are not particularly good thermal insulators. Conversely, most thermal insulators, such as the amorphous phase-change material germanium antimony telluride (Ge2Sb2Te5), are not very good electrical insulators. The researchers got the best of both worlds by developing a periodic dielectric structure, known as a superlattice-like (SLL), for integration into the PCRAM. The SLL dielectric, which comprises alternating layers of SiO2 and Ge2Sb2Te5 (see image) each just 2–3 nanometers thick, is both a good thermal insulator and a good electrical insulator.
The SLL dielectric in the PCRAM device reduces heat loss from the phase-change material, allowing the phase transition to be driven more efficiently. Consequently, the resulting PCRAM needs smaller currents, less power and less time to switch between the amorphous and the crystalline states. At the same time, the excellent electrical insulation provided by the SLL dielectric prevented current-driven breakdown, leading to a device endurance of more than a billion cycles.
The researchers believe their findings could help accelerate the development of energy-efficient, high-speed PCRAM, which could replace the use of conventional types of RAM, such as flash memory, in electronic devices. “We have already identified techniques to further improve the performance of PCRAM,” says Loke. “For example, by reducing the size of the memory cell, we can expect even higher speeds and lower power consumption levels.”
The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute
 Loke, D. et al. Superlatticelike dielectric as a thermal insulator for phase-change random access memory. Applied Physics Letters 97, 243508 (2010).
IHP presents the fastest silicon-based transistor in the world
05.12.2016 | IHP - Leibniz-Institut für innovative Mikroelektronik
High-precision magnetic field sensing
05.12.2016 | ETH Zurich
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
05.12.2016 | Power and Electrical Engineering
05.12.2016 | Materials Sciences
05.12.2016 | Power and Electrical Engineering