Meaning
Electrical degradation mechanism involves the tunneling of electrons through a thin dielectric layer under a high electric field. Fowler-Nordheim stress is the primary physical process used to program and erase cells in non-volatile memory devices. While necessary for operation, the repeated passage of charge carriers eventually damages the oxide layer.
Oxide Breakdown
The integrity of the tunnel oxide determines the endurance of the memory component. Each time fowler-nordheim stress is applied, the high voltage pushes electrons through the barrier into the floating gate. Over many thousands of cycles, this stress leads to a shift in the threshold voltage of the transistor, making it harder to distinguish between a programmed and an erased state.
It reduces the data retention period.
Acceleration Rate
Elevated temperatures increase the kinetic energy of the electrons and worsen the damage caused by the electric field. Managing fowler-nordheim stress requires careful control of the voltage pulses during the write operation. If the pulses are too long, the oxide fails prematurely, resulting in a permanent bit error that the controller cannot correct.
Error Correction
System architects implement wear leveling and bad block management to mitigate the effects of this aging process. When fowler-nordheim stress causes a block to fail its verification test, the controller retires that portion of the silicon.
