A semiconductor device having a capacitor includes a substrate which has a transistor, a first insulating pattern which is formed on the substrate and does not overlap a first contact node formed in the substrate, a second insulating pattern which is formed on the substrate, does not overlap a second contact node formed in the substrate, and is separated from the first insulating pattern, a first lower electrode which is formed on part of the substrate and sidewalls of the first insulating pattern, a second lower electrode which is formed on part of the substrate and sidewalls of the second insulating pattern, a dielectric layer pattern which is formed on the first lower electrode and the second lower electrode, and an upper electrode which is formed on the dielectric layer pattern. Related fabrication methods are also discussed.