Iridium is attractive for improving flash memory chips

Dec 14, 2010

One of the rarest metals on Earth may be an excellent option for enabling future flash memory chips to continue to increase in speed and density, according to a group of researchers in Taiwan.

"Incorporating nanocrystals of into the critical floating gate portion of designs shows both excellent memory properties as well as stability in the high temperatures used in processing such ," says the research team leader, Wen-Shou Tseng of Taiwan's Center for Measurement Standards, Industrial Technology Research Institute. The research results appears in the journal , which is published by the American Institute of Physics. His colleagues included students and professor at the nearby National Chiao Tung University and Chung Hua University.

This team chose iridium -- a hard, dense and corrosion-resistant metal in the platinum family that is one of the rarest metals found in the earth's crust -- because unlike most alternatives, it has two desired properties: Iridium holds its electrons strongly (it has a high "work function", which is well-known to correlate with excellent memory properties), and its melting point of nearly 2,500 degrees Celcius is well beyond the 900 C annealing temperature that many chips must survive during manufacturing. Fortunately only a billionth of a billionth of a gram of iridium would be needed for each gate.

Researchers worldwide are investigating new ways to improve the popular flash memory, which is the nonvolatile memory chip design used in virtually all digital cameras and mobile electronics and, increasingly, in solid-state drives for laptop computers. The easiest way for future flash memories to hold more data and read/write faster, is to shrink the dimensions of the existing chip design, including the floating gate. But today's gate design has already progressed to the point where it cannot get much smaller before it can no longer retain the electrical charges that actually store the data. Nanocrystals have been proposed as a rather simple change that can improve memory chip performance without changing the tried-and-true floating-gate design.

In recent years, many different metals have been investigated for their nanocrystal potential. Nickel and tungsten, for example, are attractive for, respectively, a high work function and thermal stability. But they and other elements lack both needed properties. It is rare, indeed, that iridium has both needed qualities, Tseng says.

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More information: The article, "Formation of iridium nanocrystals with highly thermal stability for the applications of nonvolatile memory with excellent trapping ability" by Terry Tai-Jui Wang, Chang-Lung Chu, Ing-Jar Hsieh, and Wen-Shou Tseng appears in the journal Applied Physics Letters. See: link.aip.org/link/applab/v97/i14/p143507/s1

Provided by American Institute of Physics

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Sonhouse
5 / 5 (2) Dec 14, 2010
It might only take 'a billionth of a billionth' of a gram for a gate but there better be a vigorous recycling effort because the sputtering machines or CVD's (chemical vapor deposit) or other plasma based machines have a lot of built in waste. I know that for a fact having worked in the semiconductor field for decades.

After all, SOMEONE has to be an Indium giver:)
Just_some_guy
5 / 5 (2) Dec 14, 2010
If Iridium is one of the rarest metals on the planet, then how on earth can it be "...an excellent option for enabling future flash memory chips...". I think it's a TERRIBLE option to waste this precious material on a consumer product like flash memory.
fmfbrestel
5 / 5 (1) Dec 14, 2010
Agree with both above comments. If it cant be done with common materials it's not going to get done.
damnfuct
not rated yet Dec 15, 2010
Could always just aim at mining asteroids as a source of iridium. Maybe crash them into the moon and collect.
kaasinees
1 / 5 (1) Dec 15, 2010
Yeah great idea, ram objects into an object that affects our weather.

Please... this website is for science not idiocy.
damnfuct
not rated yet Dec 15, 2010
The point was that it's very unrealistic that humans could get to any asteroids, mine it, and then get back with our current technology. It would be easier to send an engine to the asteroid and nudge it to the moon, where there could be a base to collect such minerals. The moon is 7.3477 × 10^22 kg; properly crashing a couple pebbles into it wouldn't change much. Too close to home? Use mars as a base. The whole point is to identify something desirable/profitable so that someone actually tries to get out into space, because it sure as sh*t hasn't happened for the last 40 years, and won't happen until lots of money is involved.
damnfuct
not rated yet Dec 15, 2010
(dupe from form errors)
kaasinees
not rated yet Dec 15, 2010
@damnfuct
How much does a launching cable on an aircraft carrier weigh compared to an aircraft ?
Graeme
not rated yet Dec 15, 2010
For damnfunct, it could be better to return items to earth rather than the moon. A specially shaped iridium meteorite could be accurately targeted at earth from the asteroid and retrieved. But we are going to need a multibillion dollar iridium industry before any of this is worth doing.