In one embodiment, to fabricate a semiconductor device, a first insulation interlayer is formed on a substrate. A contact pad is formed through the first insulation interlayer. An etch stop layer and a second insulation interlayer are sequentially formed on the first insulation interlayer and the pad. A contact hole exposing at least a portion of the contact pad is formed by partially etching the second insulation interlayer and the etch stop layer. A preliminary lower electrode is formed in the hole. The preliminary lower electrode is isotropically etched to form a lower electrode contacting the contact pad. A dielectric layer and an upper electrode are sequentially formed on the lower electrode.