A semiconductor device includes a lower electrode on a substrate, a capacitor dielectric layer on the lower electrode, and an upper electrode on the capacitor dielectric layer. The capacitor dielectric layer includes a base layer on the lower electrode and a dielectric particle layer in at least a portion of the base layer. The base layer includes a first dielectric material, and the dielectric particle layer extends at least partially continuously along a thickness direction of the capacitor dielectric layer and includes a second dielectric material different from the first dielectric material.