A method to easily check whether the flash memory is a second-hand recycled item will be developed

Built in smartphone etc.Flash memoryBecause it has a long lifetime, there are cases where it is sold by misrepresenting that it is "brand new" by removing the flash memory from the old and discarded device. A technology that can easily uncover this fraud is developed by the research team of the University of Alabama.

That New Memory Smell: Tech Can Tell if Your Flash is New or Recycled - IEEE Spectrum
https://spectrum.ieee.org/tech-talk/semiconductors/memory/that-new-memory-smell-tech-can-tell-you-if-your-flash-is-new-or-recycled

This technology utilizes the feature of flash memory that defects of "cells" which record information every time it is used repeatedly increase. Flash memory records information by out electrons to the "floating gate" on the inside of the cell, but to behave as read, defective portion called "lattice defects" in the insulating layer called a tunnel oxide film is increased Then, deterioration progresses. Once this layer is degraded, this cell will no longer be usable anymore.

Normally, a voltage of 5 volts is applied when driving a flash memory, but in the research team led by Associate Professor Biswadit Ray of the University of Alabama, the element is recycled by applying a voltage of plus 20 volts and minus 20 volts We have created a mechanism to judge whether it is a product or not. According to Mr. Ray, cells in the flash memory have the characteristic that the number of defective cells increases each time reading / writing repeats, and the erase time to erase memory information becomes longer. Ray et al. Have found that this feature is the most effective measurement standard for knowing the "age" of the memory element.

Byyellowcloud

According to Ray, this mechanism can be easily used, and it can be executed even with a smartphone. Moreover, it is also a feature that it has high accuracy, and it seems that it can be judged as "recycled item" even in the flash memory which only 3% of the product life has not elapsed.

However, it is not limited to this, and it seems that the research team is developing an inspection method with even higher performance. The new method "program disturb", which is still in the stage before publication, usually causes the "page" of memory with about 16 kilobytes as one unit to repeat reading and writing many times, and the memory inversion (= Error) to check the rate of occurrence. With this method, it is said that it can be judged that it is a recycled item even in the flash memory that only 1% of the lifetime has passed since it was brand new.

Mr. Rei says, "In fact there are many cases where we sell a flash memory that is a recycled product as a new product and sell it, and such a memory clears the usual inspection without difficulty," said the newly developed inspection According to the method you can detect fraudulent act of selling an old memory as a brand new.

ByHellebardius