A method for fabricating a bottom electrode structure for a semiconductor capacitor. The method according to the present invention includes providing an interlayer insulating layer having a conductive plug formed therein. A first bottom electrode layer is formed on the interlayer insulating layer. An oxygen diffusion barrier layer is formed on the first bottom electrode layer. A second bottom electrode layer is formed on the first oxygen diffusion barrier layer. Thereafter, portions of the second bottom electrode layer, first oxygen diffusion barrier layer, and first bottom electrode layer are selectively removed to form a bottom electrode pattern. A third bottom electrode is formed on side walls of the bottom electrode pattern.