Metal-insulator-metal RF bypass capacitor using niobium oxide (Nb2O5) with HfO2/Al2O3 barriers

A high capacitance density (C/sub density/) metal-insulator-metal (MIM) capacitor with niobium pentoxide (Nb₂O₅) whose k value is higher than 40, is developed for integrated RF bypass or decoupling capacitor application. Nb₂O₅ MIM with HfO₂/Al₂O₃ barriers delivers a high C/sub density/ of >17 fF/μm² with excellent RF properties, while maintaining comparable leakage current and reliability properties with other high-k dielectrics. The capacitance from the dielectric is shown to be stable up to 20 GHz, and resonant frequency of 4.2 GHz and Q of 50 (at 1 GHz) is demonstrated when the capacitor is integrated using Cu-BEOL process.