Slashdot Mirror

← Back to Stories (view on slashdot.org)

"Self-Healing" NAND Flash Memory That Can Survive Over 100 Million Cycles

Posted by Unknown on from the forged-in-the-fires-of-mount-nand dept.

another random user writes with an interesting use of 800C heating elements to keep flash working longer. It's long been known that heating NAND to temperatures around 250C can restore life, but doing so was practically impossible. From the article: "Engineers at Macronix have a solution that moves flash memory over to a new life. ... They redesigned a flash memory chip to include onboard heaters to anneal small groups of memory cells. Applying a brief jolt of heat to a very restricted area within the chip (800 degrees C) returns the cell to a 'good' state. ... According to project member HangTing Lue, the annealing can be done infrequently and on one sector at a time while the device is inactive but still connected to the power source. It would not drain a cellphone battery, he added." It's still a long way from commercialization, but if it works on a small scale...

15 of 76 comments (clear)

  1. 800C? by girlintraining · · Score: 3, Interesting

    What are the odds they'll let something that can heat up that much on an airplane, once they read this article? :\ More seriously, I assume this is over a very, very small area, and the chip dissipates that heat within a few minutes, and that it would only be warm to the touch for a few moments... but I still gotta ask: Is there the possibility of catastrophic failure? Like if the chip was maliciously reprogrammed to trigger all the heating elements simultaniously?

    --
    #fuckbeta #iamslashdot #dicemustdie
    1. Re:800C? by space+fountain · · Score: 5, Interesting

      Probably not enough power.

    2. Re:800C? by mfwitten · · Score: 5, Informative

      As you later hint, a high temperature does not imply a great deal of heat. Also, a hardware fail-safe (i.e., a fuse) is the obvious solution to any such maliciousness.

    3. Re:800C? by Anonymous Coward · · Score: 5, Informative

      You do realize that Incandescent light bulbs are at 3000K or so. So, they have been letting things get over 800C since the beginning of commercial airlines.

    4. Re:800C? by hamjudo · · Score: 5, Insightful

      The very, very small area is probably a few orders of magnitude smaller than your concept of very very small. The ieee article says it will take months to test 1 billion cycles. There are on the order of 10 million seconds in 4 months, which means the researcher thinks he can test at the rate of 100 cycles per second. In other words, the regions are so small, it takes on the order of 10ms to cool enough for the next test cycle.

    5. Re:800C? by timeOday · · Score: 5, Informative
      To prevent uncontrolled energy dissipation you can use a fuse.

      Fun fact: the spark plug in your car creates a temperature of 60,000 K (a little over 107,000 F). A cheap 4" (100 mm) magnifying glass can generate a temperature of over 600C. So, like you said, it's all about duration and area.

    6. Re:800C? by girlintraining · · Score: 3, Insightful

      You do realize that Incandescent light bulbs are at 3000K or so.

      I do. Do you realize that congress isn't exactly known for its firm grasp of science? Remember... they banned people from carrying more than a couple ounces of liquids out of fear they could be used to create binary explosives because that was the plot of a Die Hard movie, not because there was any evidence terrorists had any plans of using it, or that it would even provide the explosive force necessary. As a result, people flying home after surgery have had their ice packs confinscated, they've been forced to put diabetic pumps through metal detectors and body scanners (rendering them inoperative and posing an immediate threat to the life of the passenger), etc.

      So I posed the question to underscore the line of questioning that average person would have about such devices.... and instead I have my intelligence insulted. No matter how correct you may be, that is not an excuse for poor form.

      --
      #fuckbeta #iamslashdot #dicemustdie
    7. Re:800C? by jabuzz · · Score: 4, Informative

      It was a bit more than intelligence reports. They (that being the British) actually had a group under surveillance as they where planning attack using liquid explosives. They had video footage of them planning it all and testing there methods of concealment and talking about it. This was played on national TV news here in the UK after the trials.

      In the end they had to swoop early as they had shared their intelligence with the USA, who then threatened to blow the cover unless they where arrested immediately.

      The problem at least initially is that they where not sure that they had all members of the cell, and whether there where other cells going to be carrying out a similar operation, hence the initial draconian restrictions.

      http://en.wikipedia.org/wiki/2006_transatlantic_aircraft_plot

    8. Re:800C? by bsdaemonaut · · Score: 3, Informative

      In an incandescent light bulb the filament inside is approximately that hot. If you don't want to take my word for it, from http://en.wikipedia.org/wiki/Color_temperature, "An incandescent lamp's light is thermal radiation and the bulb approximates an ideal black body radiator, so its color temperature is essentially the temperature of the filament."

    9. Re:800C? by Muad'Dave · · Score: 4, Informative

      Did you REALLY think the filament of an ordinary incandescent tungsten bulb operates at 4940.33 degrees Fahrenheit (2727 degrees C)? Seriously?

      Yes, I do. Absent phosphors, the only way for a filament to have a color temperature of 3000K is to be at 3000K. From the article:

      "An electric current heats the filament to typically 2,000 to 3,300 K (3,140 to 5,480 F)), well below tungsten's melting point of 3,695 K (6,191 F)."

      and

      "Tungsten is the metal with the highest melting point, 3,695 K (6,191 F). A 50-hour-life projection bulb, for instance, is designed to operate only 50 C (122 F) below that melting point."

      --
      Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
  2. cant wait by Anonymous Coward · · Score: 3, Funny

    I cant wait for the first YouTube guide telling they should put flash memory in the oven to fix it. That will translate into baking cellphones ... and you know someone will try it.

  3. Interesting by certsoft · · Score: 4, Interesting

    Back around 1976 I was working in a group that used Intel 4004 processors and 1702A EPROM. They found they could get more program/erase cycles out of a 1702A if they periodically baked them in an oven.

  4. High temp but low energy by Yarhj · · Score: 5, Informative

    This story has popped up a few places already, and 90% of the comments are always "800C! But what if it catches fire?"

    Yes, the floating gate is heated to 800C, but the volume of the heated area is on the order of a few hundred cubic nanometers. The energy involved in heating a volume that small is, well, incredibly small, and dissipates rapidly into rest of the chip. Your flash memory will not burst into flame. It will not require significantly more energy from your battery, and it will not require special clearance from the TSA to bring it on a plane.

    The real challenge here is not coping with high temperatures, but rather balancing the increase in cell lifetime with the increase in die size. If the 100 million cycles number is completely accurate, then there's not much question that this technology will make its way into a lot of flash, but if that upside is only for a few (or even most) of the bits on a die, then things get more complicated

    For more info run through the comments from the Ars Technica writeup of the same story: http://arstechnica.com/science/2012/11/nand-flash-gets-baked-lives-longer/

    1. Re:High temp but low energy by KIFulgore · · Score: 4, Funny

      That's a good point... I've read a lot of comments from people freaking out about being able to bring these on a plane.

      I was once boarding a plane and accidentally scuffed my feet across the carpet. I brushed my hand by someone else and triggered a static arc that must have been close to 50,000 degrees. The plane was still able to take off. True story.

      --
      - For every action, there is an equal and opposite criticism.
  5. Can we shoot Sandforce first? by Miamicanes · · Score: 3, Interesting

    Before everyone gets worked into frothy concern about flash write cycles, keep in mind that the #1 cause of failure & data loss on Sandforce-based controllers is a toxic mess of piss-poor proprietary firmware that's brittle, bitchy, and will brick the drive in self-defense if it corrupts its internal database, then decides you're trying too hard to salvage your data by trying to use something like dd_rescue on it. Oh, and their decision to save a buck by omitting the supercapacitor that's supposed to guarantee that it always has enough power to finish its current write.

    Read the Agility/Vertex 2 & 3 forums at ocz if you think I'm making this up. Basically, Sandforce drives have mandatory encryption that can't be disabled to maximize your odds of successful data recovery, but they also employ active countermeasures to detect "hacking attempts" that usually result in the drive ending up in "panic mode".

    I wouldn't touch a Sandforce-tainted SSD with a dirty, tetanus-infected pole. They deserve to be sued into oblivion by class-action lawsuits. At the VERY least, they should give us the option of setting our own encryption key (to a value WE know), and a way to rip the bits from a borked drive for offline recovery. The most infuriating thing about data death by Sandforce is the knowledge that 99.99% of your data is *there*, but you aren't allowed to recover it due to their fucked up business policy.