BEOL compatible high-capacitance MIMCAP structure using a novel high k material

Abstract

We demonstrate a MIM capacitor structure using ZrO2 for the dielectric layer. This exhibits a 25% capacitance increase with minimal leakage current increase compared to Hf based dielectrics, extending the usefulness of MIM on-chip decoupling capacitors. The MIM structure, suitable for BEOL processing is TiN/ZrO2/TiN combined with an anneal which is shown to improve the capacitance vs. leakage performance compared to doped and undoped HfO2 based control structures. GI-XRD measurements demonstrate that the capacitance increase corresponds with a phase transformation from amorphous to cubic phase, which is shown to have a dielectric constant (k) up to 35. Reliability models based on hard-breakdown (HBD) show that this structure exceeds the end-of-life targets.