A capacitor structure and a semiconductor device, the capacitor structure including a lower electrode on a substrate; a seed layer on the lower electrode; a dielectric layer on the seed layer; and an upper electrode on the dielectric layer, wherein the dielectric layer includes a ternary metal oxide having a chemical formula of ABO3, in which each of A and B is independently a metal, and the seed layer includes a ternary metal oxide containing the same elements as that of the dielectric layer, the ternary metal oxide having a chemical formula of ABO3-x, in which each of A and B is the same metal as A and B of the ternary metal oxide having a chemical formula of ABO3, 0