Integrated circuit device and method for manufacturing thereof

In some methods, a contact is formed over a substrate, and a bottom electrode layer is formed over the contact. A first dielectric layer is formed to cover a peripheral portion of the bottom electrode layer but not a central portion of the bottom electrode layer. A second dielectric layer is formed over the first dielectric layer. The second dielectric layer includes a central dielectric region that contacts the central portion of the bottom electrode layer, and a peripheral dielectric region over the peripheral portion of the bottom electrode. A step dielectric region connects the central and peripheral dielectric regions. A top electrode layer is formed over the second dielectric layer. The top electrode layer includes a central top electrode region, a peripheral top electrode region, and a step top electrode region directly above the central dielectric region, the peripheral dielectric region, and the step dielectric region, respectively.