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-TiO
₂
/SiO
₂
stacked dielectric are explored in this letter. The crystalline TiO
₂
possesses a high permittivity while the SiO
₂
provides a negative quadratic voltage coefficient of capacitance (
VCC
-α) to cancel out the positive
VCC
-α from the crystalline TiO
₂
. These desirable properties render MIM capacitors with high performance in terms of a capacitance density of 11.9 fF/μm
²
with a
VCC
-α of 90 ppm/V
²
. With additional N
₂
plasma treatment on the crystalline TiO
₂
, 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/V
²
with slight degradation in capacitance density to 11.2 fF/μm
²
, which well meets the requirement in 2018 set by ITRS.