A method for fabricating a nonvolatile memory device includes forming a substrate structure having a tunnel dielectric layer and a floating-gate conductive layer formed over an active region defined by a first isolation layer forming a first inter-gate dielectric layer and a first control-gate conductive layer over the substrate structure, forming a trench by etching the first control-gate conductive layer, the first inter-gate dielectric layer, the floating-gate conductive layer, the tunnel dielectric layer, and the active region to a given depth, forming a second isolation layer to fill the trench; and forming a second control-gate conductive layer over the resultant structure having the second isolation layer formed therein.