A colleague told me that in a modern SLC flash memory cell there are about 400 electrons.

However, I can't find any reference to this.

Flash memory cells can be thought of as little buckets of electrons on the floating gate of a transistor. When they have enough excess electrons, the transistor switches. The gate floats, so the transistors don't drain away.

I'm looking for a reference to how many electrons are in a modern SLC flash memory cell.

EDIT: More references:

  • 2
    \$\begingroup\$ How many atoms are in the cell and how many electrons does each of those atoms have? \$\endgroup\$
    – Transistor
    Jun 13, 2020 at 15:11
  • \$\begingroup\$ Probably closer to 40,000 but next year this might be 20,000 and so nobody's going to really be able to produce an answer that survives the test of time. How much capacitance does a floating gate have? How much voltage (take a guess at 5 volts).... Q=CV etc.. \$\endgroup\$
    – Andy aka
    Jun 13, 2020 at 15:27
  • \$\begingroup\$ Hi @Andyaka, can you provide a reference for 40,000? \$\endgroup\$
    – vy32
    Jun 13, 2020 at 15:28
  • 1
    \$\begingroup\$ I guessed based on 1 fF gate capacitance and a gate charge voltage of 5 volts. \$\endgroup\$
    – Andy aka
    Jun 13, 2020 at 15:29

1 Answer 1


I found a paper, Direct Measurements of Charge in Floating Gate Transistor Channels of Flash Memories Using Scanning Capacitance Microscopy that says in its introduction:

Indeed, the recent technologies store fewer and fewer electrons, down to fewer than 1000 electrons for 90nm-node NAND Flash.

This paper is from 2006, so more modern chips may well be down in the range that your colleague mentioned. Both geometry sizes and voltages have shrunk since then.

  • \$\begingroup\$ It would be interesting to know how V-NAND change the technology and number of electrons. \$\endgroup\$
    – FarO
    Aug 12, 2022 at 8:46

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