Editing Flash memory (section)

====Programming====
[[Image:Flash-Programming.svg|thumb|left|Programming a NOR memory cell (setting it to logical 0), via hot-electron injection]]
[[File:Flash erase.svg|thumb|right|Erasing a NOR memory cell (setting it to logical 1), via quantum tunneling]]

A single-level NOR flash cell in its default state is logically equivalent to a binary "1" value, because current will flow through the channel under application of an appropriate voltage to the control gate, so that the bitline voltage is pulled down. A NOR&nbsp;flash cell can be programmed, or set to a binary "0" value, by the following procedure:

* an elevated on-voltage (typically >5&nbsp;V) is applied to the CG
* the channel is now turned on, so electrons can flow from the source to the drain (assuming an NMOS&nbsp;transistor)
* the source-drain current is sufficiently high to cause some high energy electrons to jump through the insulating layer onto the FG, via a process called [[hot carrier injection|hot-electron injection]].