Oxygen Species in HfO{sub}2 Films: An in Situ X-Ray Photoelectron Spectroscopy Study

摘要

The chemical bonding of O atoms in HfO{sub}2 films on Si was investigated by in situ X-ray photoelectron spectroscopy in the O1s spectral region. In addition to trivial O forming only O-Hf bonds, O1s signals corresponding to nontrivial secondary O (O{sub}(sec)) were also observed and angle-resolved photoelectron analysis was employed to quantitatively separate surface and bulk O{sub}(sec) contributions. Surface O{sub}(sec) was assigned to surface O-H groups generated either by room temperature water vapor exposure or by 600°C H{sub}2 annealing. Bulk O{sub}(sec) was assigned to O-O or O-H bonds located in HfO{sub}2 amorphous regions and grain boundaries. For some of the processing routes employed here, we observed additional, water-induced bulk O{sub}(sec), which was attributed to dissociative water absorption in HfO{sub}2 amorphous regions and O-depleted grain boundaries.