Abstract: A resistive random access memory cell includes a first electrode layer, an oxygen reservoir layer, a variable resistance layer, and a second electrode. The first electrode layer is located on a dielectric layer, and includes a body part extending in a first direction and multiple extension parts connected to a sidewall of the body part and extending in a second direction. The second direction is perpendicular to the first direction. The oxygen reservoir layer covers the first electrode layer. The variable resistance layer is located between the first electrode layer and the oxygen reservoir layer. The second electrode is located above a top surface of the oxygen reservoir layer and around an upper sidewall of the oxygen reservoir layer.