A method of manufacturing a memory cell includes the following steps. A channel material is formed to contact a source line and a bit line. A ferroelectric (FE) material is formed to contact the channel material. A word line is formed to contact the FE material. The FE material is disposed between the channel material and the word line. The word line includes a bulk layer. The bulk layer includes a first metal layer and a second metal layer. The second metal layer is sandwiched between the first metal layer and the FE material.