Intrinsic electron traps in atomic-layer deposited HfO2 insulators
F Cerbu and O Madia and DV Andreev and S Fadida and M Eizenberg and L Breuil and JG Lisoni and JA Kittl and J Strand and AL Shluger and VV Afanas'ev and M Houssa and A Stesmans, APPLIED PHYSICS LETTERS, 108, 222901 (2016).
Analysis of photodepopulation of electron traps in HfO2 films grown by atomic layer deposition is shown to provide the trap energy distribution across the entire oxide bandgap. The presence is revealed of two kinds of deep electron traps energetically distributed at around E-t approximate to 2.0 eV and E-t approximate to 3.0 eV below the oxide conduction band. Comparison of the trapped electron energy distributions in HfO2 layers prepared using different precursors or subjected to thermal treatment suggests that these centers are intrinsic in origin. However, the common assumption that these would implicate O vacancies cannot explain the charging behavior of HfO2, suggesting that alternative defect models should be considered. Published by AIP Publishing.
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