A process for fabricating a capacitor suitable for forming a bottom electrode layer of the capacitor on a substrate. First, a first dielectric layer is formed on a substrate. Then, a portion of the first dielectric layer is removed to form a contact hole. A conductive plug is formed within the contact hole. A seed layer is formed on the conductive plug. A sacrifice layer is formed on both the seed layer and the first dielectric layer. A predetermined region of the sacrifice layer is removed to form a recess so as to expose the seed layer. Then, a bottom electrode layer is formed by electroplating within the recess. The sacrifice layer is removed afterwards. Finally, a second dielectric layer and a top electrode layer are formed on the bottom electrode layer in sequence. The present invention is characterized in that it does not require a direct etching process on a platinum material to. form the bottom electrode layer. As a result, problems encountered during the platinum etching process such as the difficulty in controlling the critical dimension of an etched platinum bottom electrode layer can be overcome.