We report on a numerical investigation in which memory characteristics of
double floating-gate (DFG) structure were compared to those of the conventional
single floating-gate structure, including an interference effect between two
cells. We found that the advantage of the DFG structure is its longer retention
time and the disadvantage is its smaller threshold voltage shift. We also
provide an analytical form of charging energy including the interference
effect.Comment: 4 pages, 4 figure