X-ray absorption and emission spectroscopy at the Hf L1 edge of hafnium-(silicon)-oxide ultra-thin films

X-ray absorption and emission spectroscopic study at the Hf L1 edge was applied to investigate the local structure around hafnium atoms in Hf(Si)Ox ultra-thin films, which are the most promising candidates for the high-k gate dielectric material of next generation CMOS devices. HfSiOx showed an extra absorption above the Hf-L1 threshold, which is not seen in HfOx. HfSiOx also had stronger Compton scattering peak in Hf-Lγ emission region, and smaller Hf-Lγ2/Lγ3 ratio, compared with those of HfOx. These differences should be caused by partial replacements of hafnium atoms by silicon atoms as the second nearest neighbors of a hafnium atom.