A memory cell structure and method to form such structure. The method partially comprised of forming a via within an oxidizing layer, over the center of a bottom electrode. The method includes depositing a via spacer along the sidewalls of the via and oxidizing the via spacer. The via spacer being comprised of a material having a Pilling-Bedworth ratio of at least one and one-half and is an insulator when oxidized. The via area is reduced by expansion of the via spacer during the oxidation. Alternatively, the method is partially comprised of forming a via within a first layer, over the center of the bottom electrode. The first layer has a Pilling-Bedworth ratio of at least one and one-half and is an insulator when oxidized. The method also includes oxidizing at least a portion of the sidewalls of the via in the first layer.