Not sure where you get this idea from.  SSD are NAND transistors.  Even at 20nm the transistors are 30 to 40 atoms across and each Silicon atom has 14 atoms electrons. No silicon circuit works on individual electrons.  Retrieving or writing a bit of flash ends up involving millions of electrons.  Maybe you are conflating MLC and TLC (storing two or three bits per cell) with number of electrons?  Not sure.