Physical and Electrical Characterization of Metal–Insulator–Metal Capacitors With $\hbox{Sm}_{2}\hbox{O}_{3}$ and $\hbox{Sm}_{2}\hbox{O}_{3}/\hbox{SiO}_{2}$ Laminated Dielectrics for Analog Circuit Applications

We report the first demonstration of metal-insulator-metal (MIM) capacitors with Sm
₂
O
₃
/SiO
₂
laminated dielectrics featuring low quadratic voltage coefficient of capacitance (VCC) and high capacitance density for precision analog circuit applications. In comparison with a HfO
₂
MIM dielectric, the Sm
₂
O
₃
MIM dielectric is found to show a smaller quadratic VCC and a similar dielectric constant. We also investigated the cancellation of the positive quadratic VCC of Sm
₂
O
₃
through its combination with a SiO
₂
layer having a negative quadratic VCC. Thus, MIM capacitors with a Sm
₂
O
₃
/SiO
₂
laminated dielectric were fabricated with various Sm
₂
O
₃
and SiO
₂
thickness combinations. Capacitors with the Sm
₂
O
₃
/SiO
₂
laminated dielectric exhibit tunable quadratic VCC and high capacitance density. Very low quadratic VCC at various capacitance densities were achieved. The leakage current mechanism is related to Poole-Frenkel emission at a high positive bias. A smaller quadratic VCC is obtained at higher frequencies. We also conducted an extensive physical characterization of Sm
₂
O
₃
using transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy.