Effect of Nitrogen Passivation on the Performance of MIM Capacitors With a Crystalline- Stacked Insulator

摘要

$hbox{TiO}_{2}!/hbox{SiO}_{2}$ stacked dielectric-based metal–insulator–metal capacitors with different thermal and nitrogen plasma treatments (NPTs) were explored in this letter. As the $hbox{TiO}_{2}$ dielectric crystallizes from amorphous phase after a thermal treatment, capacitance density increasing from 7.7 to 11.9 $hbox{fF}/muhbox{m}^{2}$ 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 $hbox{TiO}_{2}$ film, devices still keep a satisfactory capacitance level of 11.2 $hbox{fF}/mu hbox{m}^{2}$ while exhibiting suppressed leakage current by a factor of 53, a lower quadratic voltage coefficient of capacitance $(hbox{VCC-}alpha)$ of 30 $hbox{ppm/V}^{2}$, near frequency dispersion-free capacitance, a better temperature coefficient of capacitance of 82 $hbox{ppm}/^{circ}hbox{C}$ , 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.