SRAM and flash memory
Which correctly describes how data is written to and erased from flash memory?
- ACharge is stored in a capacitor
- BThe magnetization direction of a magnetic layer is changed
- CElectrons are moved into or out of a floating gate or charge-trap layer, changing the transistor's threshold voltage
Show answer and explanation
Answer: C. Electrons are moved into or out of a floating gate or charge-trap layer, changing the transistor's threshold voltage
A flash memory cell is a transistor with a floating gate (or charge-trap layer) under its gate that stores electrons. Applying a high voltage moves electrons in or out by tunneling current or similar mechanisms, changing the threshold voltage, and the difference distinguishes 0 from 1. Because the electrons are surrounded by insulators, they are retained when power is off.