"Self-Healing" NAND Flash Memory That Can Survive Over 100 Million Cycles 76
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...
Re:800C? (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.
Re:800C? (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.
Re:800C? (Score:5, Informative)
Fun fact: the spark plug in your car [wikipedia.org] 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 [blogspot.com]. So, like you said, it's all about duration and area.
High temp but low energy (Score:5, Informative)
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/ [arstechnica.com]
Re:800C? (Score:5, 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 [wikipedia.org]
Re:800C? (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 [wikipedia.org], "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."
Re:800C? (Score:5, 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. [wikipedia.org] 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."