A semiconductor device includes a trench defining an active region in a substrate, a first insulating layer on a bottom surface and side surfaces of the active region inside the trench, a shielding layer on a surface of the first insulating layer, the shielding layer including a plurality of spaced apart particles, a second insulating layer on the shielding layer and having first charge trapped therein, the plurality of spaced apart particles being configured to concentrate second charge having an opposite polarity to the charge trapped in the second insulating layer, and a gap-fill insulating layer on the second insulating layer in the trench.