Fast, Robust, and a Blast from the Past, Mechanical Memory Switch Outstrips Chip Technology

Nanomechanical memory cell could catapult efforts to improve data storage

There are no gears or levers involved, nor even, for those who remember such things, punch cards transported in oblong boxes. Yet research by a Boston University team led by physicist Pritiraj Mohanty does update a decidedly "old" technology in a bid to build better, faster data storage systems for today's computers.

Mohanty, an assistant professor in BU’s Department of Physics, has carved tiny switches out of silicon, fabricating mechanical switches that are thousands of times smaller than a human hair.

When put through their paces as data storage tools, these nano-sized devices were capable of functioning at densities that far exceed the physical limitations of electromagnetic systems and could retrieve information at speeds that cruise in the megahertz and gigahertz ranges, millions and billions of cycles per second, respectively.

Mohanty also found that the switches operated on miniscule amounts of power, about a million-fold less than that demanded by current systems.

“This is a new ball game,” say Mohanty. “By taking a new look at old technology, we have produced memory cells that are faster and better than those currently used. This mechanical device is a completely new approach to improving data storage.”

The researchers used electron-beam lithography to produce the beam-and-pad design of the tiny devices, carving the switches from wafers made of single-crystal layers of silicon and silicon oxide. E-beam lithography, developed for use by the integrated circuit industry, has become a staple fabrication technique for microelectromechanical (MEMS) devices, the ultra-small sensors, switches, and gears integral to the microtechnology and nanotechnology industries.

To test the device’s capabilities, the researchers clamped the nanostructure on each end, effectively suspending the beam, then drove a megahertz-frequency current through an attached electrode. When driven strongly enough, the beam switched between two different and distinct states, the needed “0” and “1” conditions commonly used to describe the process for accessing stored data.

The tiny dimensions of the device allowed it to vibrate quickly, achieving a millions-of-cycles-per-second frequency of 23.57 megahertz. This speed reflects the rate at which the device could “read” stored information. As a comparison, the hard drives in current laptops can read at a speed of a few hundred kilohertz (thousands of cycles per second) in actual operation. The researchers speculate that even smaller beams could be produced and that such devices could achieve true read speeds in the gigahertz range — billions of cycles per second.

Other advantages of this tiny mechanical memory system include its angstrom-sized “range of motion,” allowing it vibrate between states using only femtowatts of power, compared with the milliwatts or microwatts of power needed for read-write functions in current machines. The device also overcomes the superparamagnetic effect that limits contemporary systems, allowing the beams to be packed at densities that exceed the 100 gigabits per square inch that is the current ceiling. In addition, unlike conventional electronic or magneto-electronic storage systems, these nanomechanical memory cells are resilient in electrical and magnetic fields.

“They are extremely robust,” says Robert Badzey, a team member and graduate student in BU’s Department of Physics. “Not only can these mechanical switches withstand radiation disturbances, like solar flares, they also are tough enough to work even after being dropped.”

In addition to Mohanty and Badzey, the BU research team included Guiti Zolfagharkhani, a graduate student in physics, and Alexei Gaidarzhy, a graduate student in the College of Engineering’s Department of Aerospace and Mechanical Engineering. Their paper will appear in the October 18 issue of Applied Physics Letters, a journal of the American Institute of Physics. The research was supported by grants from the Nanoscale Exploratory Research program of the National Science Foundation and the Army Research Laboratory of the Department of Defense.

The Physics Department at Boston University provides research opportunities in areas such as experimental high-energy physics and astrophysics, molecular biophysics, theoretical condensed-matter physics, and polymer physics. Research in the Department of Aerospace and Mechanical Engineering includes robotics, MEMS, and nanotechnology.

Boston University, with an enrollment of more than 29,000 in its 17 schools and colleges, is the fourth-largest independent university in the United States.

Source: BU

Related stories:

Reducing Our Lead Footprint: Engineers Discover New Material to Reduce Lead in Electronics
(PhysOrg.com) -- Researchers at the University of Maryland's A. James Clark School of Engineering have discovered a new lead-free material, bismuth samarium ferrite (BSFO), for use in products ranging from biomedical imaging devices to airbag sensors to inkjet printers. If implemented commercially, it could replace a common lead-based material found in these and other electronic devices, keeping lead out of landfills and the ecosystem.
Revolution in understanding of ion channel regulation
A study at Rush University Medical Center in Chicago published this week in the online version of Biophysical Journal proposes that bubbles may control the opening and closing of ion channels. This new understanding of the channels that control much of life in health and disease provides a vital piece of the molecular puzzle.
Forces out of nothing
When a machine jams, it’s the fault of the engineer - or of physics. The latter is true at least for the first simple nanomachines which are slowed down by the Casimir effect. This force only works on the scale of a few millionths of a centimeter and makes tiny machine parts cling together.
Understanding MEMS: DARPA Award to Create Computer-Aided Design Environment for Micro-Electromechanical Systems Devices
Researchers at the Georgia Institute of Technology have received a Defense Advanced Research Projects Agency (DARPA) award to participate in a multi-university research center that will develop a computer-aided design (CAD) environment for micro-electromechanical systems (MEMS) and nano-electromechanical systems (NEMS).
Hidden order found in a quantum spin liquid
An international team, including scientists from the London Centre for Nanotechnology, has detected a hidden magnetic “quantum order” that extends over chains of 100 atoms in a ceramic without classical magnetism. The findings, which are published today by Science, have implications for the design of devices and materials for quantum information processing.
Nanoscale pasta: Toward nanoscale electronics
Pasta tastes like pasta – with or without a spiral. But when you jump to the nanoscale, everything changes: carbon nanotubes and nanofibers that look like nanoscale spiral pasta have completely different electronic properties than their non-spiraling cousins. Engineers at UC San Diego, and Clemson University are studying these differences in the hopes of creating new kinds of components for nanoscale electronics.
Physicists pioneer new super-thin technology (Update)
Researchers have used the world's thinnest material to create a new type of technology, which could be used to make super-fast electronic components and speed up the development of drugs.
Handheld windmills serve as electric generators
It’s not quite nanotechnology, but these inches-long windmills can generate small amounts of electric energy to power a variety of low-voltage applications. Since they’re made entirely of plastic, they cost just dollars to manufacture, offering potential for many uses including battery recharging, lighting in remote areas, and wireless sensors.

News discussion:

Nanotechnology news