A nonvolatile silicon/oxide/nitride/silicon/nitride/oxide/silicon (SONSNOS) structure memory device includes a first insulating layer and a second insulating layer stacked on a channel of a substrate, a first dielectric layer and a second dielectric layer formed on the first insulating layer and under the second insulating layer, respectively, and a group IV semiconductor layer, silicon quantum dots, or metal quantum dots interposed between the first dielectric layer and the second dielectric layer. The provided SONSNOS structure memory device improves a programming rate and the capacity of the memory.