A 3D flash memory is provided to includes a gate stack structure comprising a plurality of gate layers electrically insulated from each other, a cylindrical channel pillar vertically extending through each gate layer of the gate stack structure, a first conductive pillar vertically extending through the gate stack structure, the first conductive pillar being located within the cylindrical channel pillar and being electrically connected to the cylindrical channel pillar, and a second conductive pillar extending through the gate stack structure, the second conductive pillar being located within the cylindrical channel pillar and being electrically connected to the cylindrical channel pillar, the first conductive pillar and the second conductive pillar being separated from each other. The 3D flash memory also includes a ferroelectric layer disposed between gate layers of the gate stack structure and the cylindrical channel pillar.