Integration of Amorphous $\hbox {Yb}_{2}\hbox {O}_{3}$ and Crystalline $\hbox {ZrTiO}_{4}$ a

Because of a higher permittivity than Al₂O₃, a large conduction band offset and high thermal stability, a thin amorphous Yb₂O₃ layer was integrated with a ZrTiO₄ film as the gate stack for advanced Si MOS devices. With 800 °C annealing, the ZrTiO₄ film can be crystallized in orthorhombic phase with permittivity of 45.9 and a gate stack with equivalent oxide thickness of 0.86 nm can be achieved. This crystalline ZrTiO₄/Yb₂O₃ gate stack demonstrates negligible frequency dispersion in capacitance, low interface trap density of 1.86 × 10¹¹ cm^-2 eV^-1, leakage current of 6.7 × 10^-6 A/cm² at gate bias of Hatband voltage (V_FB) -1 V, and high extrapolated 10-year lifetime operating voltage of -2.9 V. These promising electrical characteristics suggest that the crystalline ZrTiO₄/Yb₂O₃ gate stack holds great potential to be applied to aggressively scaled CMOS technology.