A New Metal–Insulator–Metal Capacitor with Nickel Fully Silicided Polycrystalline Silicon Electrodes

A novel low-cost metal–insulator–metal (MIM) capacitor with a high capacitance density of ∼10.2 fF/µm2 has been developed by using nickel fully silicided (Ni-FUSI) polycrystalline silicon electrodes. The low resistivities of Ni3Si, Ni2Si, and NiSi electrodes have been achieved and determined to be around 106, 39, and 21 µΩ·cm without requiring noble metal materials. At room temperature, this MIM capacitor also displays a good leakage current density of 3.9×10-6 A/cm2 at 1 V and a quadratic voltage coefficient (α) of 2266 ppm/V2. Experiments demonstrated that Schottky emission is the dominant conduction mechanism at high temperatures and low fields under top electrode injection. The Schottky barrier heights (ΦB) at the Ni3Si/ZrO2, Ni2Si/ZrO2, and NiSi/ZrO2 interfaces were extracted firstly to be 1.15, 1.05, and 0.8 eV, respectively. Material characterization further reveals this structure highly appropriate for advanced MIM capacitors.