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

摘要

We report the first demonstration of metal–insulator–metal (MIM) capacitors with $hbox{Sm}_{2}hbox{O}_{3}/hbox{SiO}_{2}$ laminated dielectrics featuring low quadratic voltage coefficient of capacitance (VCC) and high capacitance density for precision analog circuit applications. In comparison with a $hbox{HfO}_{2}$ MIM dielectric, the $hbox{Sm}_{2}hbox{O}_{3}$ 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 $hbox{Sm}_{2}hbox{O}_{3}$ through its combination with a $hbox{SiO}_{2}$ layer having a negative quadratic VCC. Thus, MIM capacitors with a $hbox{Sm}_{2}hbox{O}_{3}/ hbox{SiO}_{2}$ laminated dielectric were fabricated with various $hbox{Sm}_{2}hbox{O}_{3}$ and $hbox{SiO}_{2}$ thickness combinations. Capacitors with the $hbox{Sm}_{2}hbox{O}_{3}/ hbox{SiO}_{2}$ 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 $hbox{Sm}_{2} hbox{O}_{3}$ using trans-nmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy.