Patent ID: 7910967

Claim:
A ferroelectric capacitor comprising: a single layer lower electrode having a U-shaped profile; an insulating interlayer around the single layer lower electrode; a ferroelectric layer on both the single layer lower electrode and the insulating interlayer around the single layer lower electrode and extending into a trench structure; and an upper electrode on the ferroelectric layer, wherein at least one diffusion barrier layer is between the insulating interlayer and the ferroelectric layer, the at least one diffusion barrier layer preventing mutual diffusion between lead (Pb) from the ferroelectric layer and silicon (Si) from the insulating interlayer, and wherein each of the insulating interlayer and the at least one diffusion barrier layer is in contact with a side of the single layer lower electrode, the at least one diffusion barrier layer being in direct contact with both the insulating interlayer and the ferroelectric layer.