Question

Flash memory works by storing charge on a floating gate that is electrically isolated from the gate to which power can be applied. The memory is “set” by applying a bias to effect tunneling into the floating gate. When unbiased the charge stays within the floating gate. However tunneling can still happen but at a much lower rate. If data can still be successfully read until the charge drops to 80% of its initial amount, what thickness of oxide is required to allow the memory to retain data for 20 years?

Notes: Barrier energy for SiO2/Si interface is 3.2 eV. Floating gate is biased to 1 volt and dgate-100nm Decay rate: λ-Tdgate/v Charge retained after time t: NNoe-t

All information is given.

Answer 1

Given that

$\lambda = Td_{gate}/\nu$

Gmounk tine, t20 yeax o e