Spectroscopic Studies of Band Edge Electronic States in Elemental High‐k Oxide Dielectrics on Si and Ge Substrates

This paper uses X‐ray absorption spectroscopy, and vacuum ultra‐violet spectroscopic ellipsometry to distinguish between i) non‐crystallinity, and ii) nano‐crystallinity in transition metal (TM) elemental oxides. Near edge X‐ray absorption spectroscopy is used to distinguish between two different scales of nano‐crystalline order. The observation of band edge Jahn‐Teller splittings in anti‐bonding states with TM p‐character correlate with the observation of nano‐crystalline‐order that can be detected by X‐ray diffraction, and establish a length scale for order, λs>3 to 4 nm, The suppression of J‐T splittings, and a spectral broadening is associated with reduced nano‐crystalline order that can be detected by atomic‐scale imaging and/or extended X‐ray absorption spectroscopy for λs<∼2.5 nm. These different states of nano‐crystalline grain‐size order for addressed in elemental transition metal oxides on both Si and Ge substrates.