SEMICONDUCTOR MEMORY DEVICE

A semiconductor memory device includes an upper electrode, a lower electrode, an anti-ferroelectric layer disposed between the upper electrode and the lower electrode and including an anti-ferroelectric, an oxide layer disposed on a first surface of the anti-ferroelectric layer and including a high dielectric material, and a metal oxide layer disposed on a second surface of the anti-ferroelectric layer opposite to the first surface. A thickness of each of the oxide layer and the metal oxide layer is less than a thickness of the anti-ferroelectric layer.