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On the nature of the high-k dielectrics leakage current reduction by post-deposition annealing

A. SKEPAROVSKI1,* , N. NOVKOVSKI1

Affiliation

  1. Institute of Physics, Faculty of Natural Sciences and Mathematics, P.O.Box 162, Skopje, 1000, Macedonia

Abstract

We have analyzed the newest reported in the literature experimental I–V characteristics of postdeposition annealed HfO2 on silicon substrates, by employing a recently developed method for describing the leakage currents through high-κ/SiO2 stacked structures, employed previously for Ta2O5. The presence of a very thin SiO2-like interfacial layer between the HfO2 and silicon and its effect on the leakage currents were explicitly included into calculations. Considering direct tunneling as a dominant conduction mechanism in SiO2 and Poole-Frenkel emission in HfO2, a satisfactory agreement with the experimental results was obtained. The possibility of some other current transport processes to be present in HfO2 and the sensitivity of the method to detect them were also discussed. Based on the obtained results, it is argued that the interfacial SiO2-like layer strongly influences the I-V characteristics of the HfO2/SiO2 structure. Experimentally observed reduction of the leakage currents after post-deposition annealing in different ambient (O2, NH3 and forming gas) of the structures, could be explained by the additional growth of the SiO2–like interfacial layer, rather than by an improved stoichiometry of the bulk HfO2..

Keywords

High-k dielectrics, HfO2, Postdeposition annealing, Leakage current.

Submitted at: Nov. 2, 2006
Accepted at: April 15, 2007

Citation

A. SKEPAROVSKI, N. NOVKOVSKI, On the nature of the high-k dielectrics leakage current reduction by post-deposition annealing, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 4, pp. 897-901 (2007)