Permittivity enhancement of hafnium dioxide high-κ films by cerium doping

Abstract

The effect of cerium doping on the dielectric properties of hafnium dioxide is reported. Thin films of cerium-doped hafnium oxide Cex–Hf1−xO2 (x=0.10,0.17,0.34) have been grown by liquid injection atomic layer deposition. After annealing at 900 °C, all films were transformed from an amorphous state into a stabilized cubic or tetragonal phase. As-deposited films of Ce0.1–Hf0.9O2 showed low hysteresis voltages and negligible flat band voltage shifts. After annealing to form the crystalline cubic or tetragonal phase, the relative permittivity (κ) increased from 25 to 32 at 100 kHz with leakage current densities at ±1 MV cm−1 of ∼1.58×10−5 A cm−2.