Via Diode in Cu Backend Process for 3D Cross-Point RRAM Arrays

In this paper, a fully logic compatible via diode is developed for high-density resistive random access memory (RRAM) array applications. This novel via diode is realized by advanced 28nm CMOS technology with Cu damascene via. The device is stacked between a top Cu via and a bottom Cu metal with a composite layer of TaN/TaON based dielectric film. An asymmetric current-voltage characteristic in this MIM structure provides a forward/reverse current ratio up to 10
⁶
. In a cross-point RRAM array, the suppression of sneak current path by incorporating this via diode enables array size to be greatly expended. Via diode provides an excellent solution for high-density embedded nonvolatile memory applications in the nano-scale CMOS technology.