On the leakage problem of MIM capacitors due to improper etching of titanium nitride

In this work, Metal-insulator-metal (MIM) capacitor structures are fabricated in a technology using TiN as electrode material. The electrical characterization revealed devices with small and large leakage currents. Scanning Electron Microscopy (SEM) inspection showed a correlation between high leakage currents and large roughness in the dielectric layer of the capacitor. Cross-section of leaky capacitors by means of a Focussed Ion Beam (FIB) showed a rough edge of the bottom electrode and the presence of particles leading to a rough dielectric layer. These artefacts are the result of improper wet chemical etching of the TiN layer. It is shown, high leakage currents and improper etching of the TiN layer are correlated