Electron spin resonance study of as-deposited and annealed (HfO2)x(SiO2)1−x high-κ dielectrics on Si

Abstract

Electron spin resonance measurements on 4 and $40\mathrm{nm}$ thick ${\left(\mathrm{Hf}{\mathrm{O}}_2\right)}_{0.6}{\left(\mathrm{Si}{\mathrm{O}}_2\right)}_{0.4}$ and ${\left(\mathrm{Hf}{\mathrm{O}}_2\right)}_{0.4}{\left(\mathrm{Si}{\mathrm{O}}_2\right)}_{0.6}$ high-$\kappa$ films on (100)Si wafers detected $P_{b0}$ and $P_{b1}$ defects at the dielectric/Si interface and verified their identities with $g$ value mapping. Annealings of a $4\mathrm{nm}$ thick ${\left(\mathrm{Hf}{\mathrm{O}}_2\right)}_{0.6}{\left(\mathrm{Si}{\mathrm{O}}_2\right)}_{0.4}$ film in nitrogen at 800 and $1000°\mathrm{C}$ monotonically lowered total interface states. In contrast, the same annealings monotonically increased the total interface states observed in $40\mathrm{nm}$ thick films of both compositions. For the $4\mathrm{nm}$ technologically relevant thickness, the annealed ${\left(\mathrm{Hf}{\mathrm{O}}_2\right)}_{0.6}{\left(\mathrm{Si}{\mathrm{O}}_2\right)}_{0.4}$ composition on (100)Si had lower interface states than the ${\left(\mathrm{Hf}{\mathrm{O}}_2\right)}_{0.4}{\left(\mathrm{Si}{\mathrm{O}}_2\right)}_{0.6}$ composition on (100)Si. After nitrogen annealing at $800°\mathrm{C}$ , a third defect believed to be the EX, appears in larger quantities in the thicker $40\mathrm{nm}$ films.