 Generally SONOS is very similar to traditional FG (floating gate) type memory cell,
but hypothetically offers higher quality storage.This is due to the smooth homogeneity of the Si3N4 film compared with polycrystalline film which has tiny irregularities.Flash requires the construction of a very high-performance insulating barrier on the gate leads of its transistors, often requiring as many as nine different steps, whereas the oxide layering in SONOS can be more easily produced on existing lines and more easily combined with CMOS logic.