Bond nature of oxygen-deficient HfO₂/Si(100) film

The authors investigate the bonding environment of an oxygen-deficient Hf O2 Si film grown by means of pulsed laser deposition, by analyzing the Hf L3 -edge extended x-ray absorption fine structure. The local characteristics around the Hf atom, such as the bond length or the number of nearest neighbors, are found to depend on the oxygen supply during film growth. The chemical states of these samples are also probed in situ by x-ray/ultraviolet photoelectron spectroscopies. The core-level binding energy and the work function for each sample are found to be correlated with the mean Hf-O bond length, implying a close connection between the chemical environment and bond nature.