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

The HfTiO/Y₂O₃ stacked dielectric is proposed as the dielectric of metal-insulator-metal (MIM) capacitor. Y₂O₃ 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 Y₂O₃ layer between HfTiO and TaN. The negative quadruple voltage coefficient of capacitance (VCC-α) of Y₂O₃ cancels out the positive VCC-α of HfTiO to achieve low VCC-α. The MIM capacitor structure with HfTiO/Y₂O₃ dielectric shows a capacitance density that is higher than 11 fF/μm² and VCC-α that is lower than 1222 ppm/V². The leakage currents at -1 and -2 V are 6.4 and 14 nA/cm², respectively. These results suggest that the HfTiO/Y₂O₃ stacked dielectric is a promising candidate for MIM capacitors.