What is the meaning of tunneling in flash memory cards?

Answer 1

"Tunneling" is short for quantum tunneling. A consequence of quantum mechanics is that particles can sometimes do things, such as moving through a barrier (as if going through a tunnel), that they don't seem to have enough energy to do. That is because of Heisenberg's Uncertainly Principle; we never know exactly how much energy a given particle has, so they may have more than we thought. Quantum mechanics is in general a counter-intuitive subject, so if this doesn't entirely make sense to you, that is a normal reaction. In any event, the practical consequence of this with regard to flash memory cards, is that there can be errors which under classical mechanics wouldn't happen, but which as a result of quantum mechanics can and do happen.