US Patent 9431604 Resistive random access memory (RRAM) and method of making

The present disclosure provides a resistive random access memory (RRAM) cells and methods of making the same. The RRAM cell includes a transistor and an RRAM structure electrically connected to the transistor. The RRAM structure includes a bottom electrode having a via portion and a top portion, a resistive material layer over the bottom electrode and having a same width as the top portion of the bottom electrode, and a top electrode over the resistive material layer and having a smaller width than the resistive material layer.