Thermal Leakage Improvement by Using a High-Work-Function Ni Electrode in High-κ TiHfO Metal–Insulator–Metal Capacitors

An unavoidable drawback when using high-κ dielectrics in capacitors is the small bandgap and the related reduction in the band-offset, which results in a large leakage current at elevated temperatures. We report improvements in the thermal leakage current by using Ni as a high-work-function top electrode for high-κ TiHfO capacitors. This avoids sacrificing the overall κ value by using a multilayer or laminate structure and results in better voltage linearity, which is important for analog/radio frequency integrated circuits.