A semiconductor device includes a lower electrode, a supporting member enclosing at least an upper portion of the lower electrode, a dielectric layer on the lower electrode and the supporting member, and an upper electrode disposed on the dielectric layer. The supporting member may have a first portion that extends over an upper part of the sidewall of the lower electrode, and a second portion covering the upper surface of the lower electrode. The first portion of the supporting member protrudes above the lower electrode.