Impact of Zr addition on properties of atomic layer deposited HfO ₂

The impact of Zr addition on microstructure of Hf O2 after high temperature processing was investigated using Rutherford backscattering, x-ray diffraction (XRD), transmission electron microscopy, and atomic force microscopy (AFM). The Zr O2 content in the films was varied from ∼25% to 75%. XRD analysis shows that adding >50% Zr O2 leads to partial stabilization of tetragonal phase of the Hfx Zr1-x O2 alloy. AFM images revealed smaller grains with Zr addition. Conducting AFM showed more uniform and tighter tunneling current distribution in Hfx Zr1-x O2 compared to Hf O2. Constant capacitance-voltage stressing performed on Hf O2 and Hfx Zr1-x O2 metal-oxide-semiconductor capacitors indicated reduced charge trapping with Zr addition.