Effect of Nitrogen Passivation on the Performance of MIM Capacitors With a Crystalline- $\hbox{TiO}_{2}/\hbox{SiO}_{2}$ Stacked Insulator

TiO
₂
/SiO
₂
stacked dielectric-based metal-insulator-metal capacitors with different thermal and nitrogen plasma treatments (NPTs) were explored in this letter. As the TiO
₂
dielectric crystallizes from amorphous phase after a thermal treatment, capacitance density increasing from 7.7 to 11.9 fF/m
²
was obtained at the price of aggravating leakage current and wider distribution in device characteristics. With NPT to well passivate grain-boundary-related defects in the crystalline TiO
₂
film, devices still keep a satisfactory capacitance level of 11.2 fF/μm
²
while exhibiting suppressed leakage current by a factor of 53, a lower quadratic voltage coefficient of capacitance (VCC-α) of 30 ppm/V
²
, near frequency dispersion-free capacitance, a better temperature coefficient of capacitance of 82 ppm/°C, and more controllable device uniformity. The mechanism for the improved electrical characteristics was further confirmed by atomic force microscope. These results suggest that NPT paves a new avenue to further advance the performance of crystalline dielectric-based devices.