Most of us have had by now a few USB sticks dying from natural causes… you unplug them (regardless, in my experience whether you've safely removed hardware) and the next time you plug them in, it is like you didn't. Nothing shows.
I'm curious – what actually happens to a flash drive when we say that a USB drive has died? Something short-circuits? Overburns? What?
Best Answer
Flash memory cells use floating gate transistors to store each bit. The "floating" part of semiconductor is surrounded by an oxide and acts like a reservoir for electrical charge. Electrons can be "tunnelled" into or out of the floating gate (through the oxide), by applying the appropriate voltage. Otherwise the charge is stuck in the floating gate, even when the power supply is removed. However, over time (after many program-erase cycles) this oxide can wear down, and the cell loses its ability to store a bit.
The controller of a flash storage device might anticipate this problem and can replace worn areas of memory with spare area. This, along with a wear-levelling strategy, should prolong the life of the drive.