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Engineers Devise a Technique To Fight Counterfeit or Recycled Smartphone Memory (ieee.org)
Flash is designed to last a decade or more of use. A lot of the gadgets that rely on it, however, are not. Shady recyclers have spotted opportunity in that mismatch, stripping out used chips and selling them as new. But fret not, there is something that can be done to address the issue. From a report: Engineers at the University of Alabama have come up with a straightforward electronic examination that can tell if a flash chip is new or recycled, even if that chip has only seen 5 percent or less of its life. And the technique is so straightforward that a smartphone app could run it on its own memory. [...] A flash memory cell is like an ordinary transistor, it has a source and a drain and a channel through which current flows under the control of voltage on the gate electrode. The difference is that the gate is split into several layers -- the control gate, the blocking oxide, the floating gate, and the tunneling oxide.
[...] Voltage on the control gate causes electrons to tunnel through that bottom oxide and get stuck inside the floating gate. This charge or its absence is the stored bit. It alters how much voltage you need to turn the transistor on in a way that you can easily measure. Erasing the bit is done by reversing the voltage and driving the charge out of the floating gate. Ray and his team took advantage of the rather high voltages -- about plus or minus 20 volts -- needed to program and erase flash. The more you program and erase a cell, the more defects will accumulate in the oxide, he explains.
[...] Voltage on the control gate causes electrons to tunnel through that bottom oxide and get stuck inside the floating gate. This charge or its absence is the stored bit. It alters how much voltage you need to turn the transistor on in a way that you can easily measure. Erasing the bit is done by reversing the voltage and driving the charge out of the floating gate. Ray and his team took advantage of the rather high voltages -- about plus or minus 20 volts -- needed to program and erase flash. The more you program and erase a cell, the more defects will accumulate in the oxide, he explains.
How nice it would be if at least technical sites such as Slashdot could get straight the difference between memory/RAM and SSD/flash storage.
Due to the wonders of the internet you can go on Ali Express or Ebay and order all sorts of electronic wonders from china REAL cheap. If you're a maker or a hobbyist you've got more available to you than ever before, for fractions of a penny on the dollar of what it used to cost 10 years ago.
When you order certain things that /should/ be pricy but are not more often than not you get something that contains recycled pulls. IGBTs, relays, things that come as packaged "modules" for integration - Like GPS modules, DiskOnChip modules, cell modems, solid state relays, potted DC-DC converters
This has its up and downs. On the down,you're getting something that's of unknown condition.. On the up,you're getting something for 5-10 bucks that costs 50-100 new. (If you can even order it as an individual at all)
You see a lot of this for hobby stuff. A big example is GPS modules - The packaged GPS module will be pulled and re-soldered on to a minimal breakout board with a voltage regulator ready for use in your project (Drones are really popular application for this)