MOS Devices With High-κ (ZrO2) x (La 2 O 3) 1-x Alloy as Gate Dielectric Formed by Depositing ZrO 2 /La 2 O 3/ZrO2 Laminate and Annealing

An amorphous (ZrO$_2$) $_x$(La $_2$O$_3$) $_{1-x}$ alloy formed by depositing a ZrO $_2$/La$_2$O $_3$/ZrO$_2$ laminate and a subsequent annealing was employed as the gate dielectric for metal-oxide-semiconductor (MOS) devices. The (ZrO$_2$) $_x$(La$_2$ O$_3$)$_{1-x}$ alloy is found to have a high permittivity κ of 26.2 with negligible amount of bulk traps, both of which are very desirable for advanced gate dielectrics. By integrating the (ZrO$_2$ )$_x$(La $_2$O$_3$) $_{1-x}$ alloy with an SiON interfacial layer as the gate stack, it displays good frequency dispersion in capacitance–voltage ($C$ –$V$) characteristics and low interfacial trap density of 1.52 × 10$^{11}$ cm$^{-2}$ eV$^{-1}$. In addition, the current conduction mechanism of the gate stack is observed to be Fowler–Nordheim tunneling and the leakage current of 3.6 × 10$^{-6}$ A/cm $^2$ at the gate voltage of −1 V for equivalent oxide thickness of 1.1 nm can be achieved, which is superior to other high-κ dielectrics. Furthermore, satisfactory reliability is verified by bias temperature instability measurement. Most importantly, this gate stack not only exhibits a promising perspective for advanced CMOS technology but introduces a more reliable process to form an alloy-based high-κ gate dielectric.