A method of forming a flash memory device in a memory cell region of a substrate includes forming a first insulating layer on the substrate, forming a first conductive layer on the first insulating layer, forming trench isolation regions in the substrate extending through the first conductive layer and the first insulating layer to define an active region in the memory cell region between the trench isolation regions, and selectively removing the first conductive layer and the first insulating layer from the memory cell region of the substrate to expose a surface of the active region between the trench isolation regions.