Abstract: A conductive diffusion barrier layer, a semiconductor device having the same, and a method for manufacturing the semiconductor device is provided. The diffusion barrier layer contains Al, N, and a metal element selected from the group consisting of Ta, Mo, Nb, and W. The content ratio of each element is between 1 and 60 mole percent. The diffusion barrier layer further contains O having a content ratio between 1 and 50 mole percent. A capacitor using the diffusion barrier layer described above exhibits a higher capacitance because the plug formed under a storage node is prevented from being oxidized and a dielectric layer having a high dielectric constant is formed.

Abstract: Methods of forming integrated circuit capacitors include the steps of forming an electrically insulating layer having a contact hole therein, on a face of a semiconductor substrate and then forming a polysilicon contact plug in the contact hole. A first capacitor electrode is then formed in electrical contact with the polysilicon contact plug. The first capacitor electrode may be formed by etching a composite of a diffusion barrier metal layer containing a nitride material (or silicide material) and a first electrically conductive layer. Alternatively, the first capacitor electrode may be formed by etching the diffusion barrier metal layer without the first electrically conductive layer thereon. The diffusion barrier metal layer inhibits parasitic migration of silicon from the polysilicon plug to the first electrically conductive layer. A protective layer of a preferred material is then electroplated onto an upper surface and on sidewalls of the first capacitor electrode.