To prevent the generation of leakage current in a capacitor by implanting a silicon layer with ions for converting it into a barrier layer and then forming a dielectric layer on the barrier layer after heat treatment and wet etching thereby, improving the quality of the dielectric layer.

An HSG layer 32 is formed on the surface of a conductive layer 30 using SiH4 and Si2H6 as reaction gases, for example, and implanted with nitrogen ions. Thereafter, a thin barrier layer 34 of silicon oxynitride or silicon nitride, for example, is formed on the HSG layer 32 through rapid heating process. Since a thin native oxide layer 33 is formed on the surface of the barrier layer 34, this is removed through wet etching process. Subsequently, a dielectric layer 36 of tantalum oxide is formed on the surface of the battier layer 34 by LPCVD, followed by the formation of a top electrode layer 38 of titanium nitride on the surface of the dielectric layer 36.