Use of a High-Work-Function Ni Electrode to Improve the Stress Reliability of Analog SrTiO₃ Metal–Insulator–Metal Capacitors

We have studied the stress reliability of low-energy-bandgap high- metal-insulator-metal capacitors under constant voltage stress. By using a high-work-function Ni electrode (5.1 eV), we reduced the degrading effects of stress on the capacitance variation (DeltaC/C), the quadratic voltage coefficient of capacitance (VCC-alpha), and the long-term reliability, in contrast with using a TaN. The improved stress reliability for the Ni electrode capacitors is attributed to a reduction of carrier injection and trapping.