Polycrystalline silicon/CoSi2 Schottky diode with integrated SiO2 antifuse: a nonvolatile memory cell

Abstract

A Schottky diode consisting of doped polycrystalline silicon (polysilicon) and CoSi2 films is described. When an SiO2 antifuse thin film is grown in between the polysilicon and CoSi2, the film stack can function as a nonvolatile one-time programmable memory cell. The cell is programmed when the SiO2 that insulates the doped polysilicon from the CoSi2 is broken down by applying a large biasing field, and unprogrammed when the antifuse is not broken down. By taking advantage of the ability to grow SiO2 directly on CoSi2, the entire device can made with only two masking steps and relatively simple tool set, while achieving high density.