MIM Capacitors With Crystalline- $\hbox {TiO}_{2}/ \hbox {SiO}_{2}$ Stack Featuring High Capacitance Density and Low Voltage Coefficient

Metal-insulator-metal (MIM) capacitors with crystalline-TiO₂/SiO₂ stacked dielectric are explored in this letter. The crystalline TiO₂ possesses a high permittivity while the SiO₂ provides a negative quadratic voltage coefficient of capacitance (VCC-α) to cancel out the positive VCC-α from the crystalline TiO₂. These desirable properties render MIM capacitors with high performance in terms of a capacitance density of 11.9 fF/μm² with a VCC-α of 90 ppm/V². With additional N₂ plasma treatment on the crystalline TiO₂, because of the effective passivation of grain-boundary-related defects and, consequently, a lower leakage current by a factor of 50, the VCC-α can be further lowered to 30 ppm/V² with slight degradation in capacitance density to 11.2 fF/μm², which well meets the requirement in 2018 set by ITRS.