High-Performance Metal–Insulator–Metal Capacitors With $\hbox{HfTiO}/\hbox{Y}_{2}\hbox{O}_{3}$ Stacked Dielectric

The
$\hbox{HfTiO}/\hbox{Y}_{2}\hbox{O}_{3}$
stacked dielectric is proposed as the dielectric of metal–insulator–metal (MIM) capacitor.
$\hbox{Y}_{2}\hbox{O}_{3}$
is more thermodynamically stable than HfTiO as contacting with TaN electrode. Interfacial layer thickness and leakage current density can be reduced by inserting a thin
$\hbox{Y}_{2}\hbox{O}_{3}$
layer between HfTiO and TaN. The negative quadruple voltage coefficient of capacitance (VCC-
$\alpha$
) of
$\hbox{Y}_{2}\hbox{O}_{3}$
cancels out the positive VCC-
$\alpha$
of HfTiO to achieve low VCC-
$\alpha$
. The MIM capacitor structure with
$\hbox{HfTiO}/\hbox{Y}_{2}\hbox{O}_{3}$
dielectric shows a capacitance density that is higher than 11
$\hbox{fF}/\mu\hbox{m}^{2}$
and VCC-
$\alpha$
that is lower than 1222
$\hbox{ppm/V}^{2}$
. The leakage currents at
$-$
1 and
$-$
2 V are 6.4 and 14
$\hbox{nA/cm}^{2}$
, respectively. These results suggest that the
$\hbox{HfTiO}/\hbox{Y}_{2}\hbox{O}_{3}$
stacked dielectric is a promising candidate for MIM capacitors.