Deep electron traps in HfO2-based metal-oxide-semiconductor capacitors

Publication date: Available online 6 January 2016
Source:Thin Solid Films
Author(s): L. Sambuco Salomone, J. Lipovetzky, S.H. Carbonetto, M.A. García Inza, E.G. Redin, F. Campabadal, A. Faigón
Hafnium Oxide (HfO2) is currently considered to be a good candidate to take part as a component in charge trapping nonvolatile memories. In this work, the electric field and time dependences of the electron trapping/detrapping processes are studied through a constant capacitance voltage transient technique on metal-oxide-semiconductor capacitors with atomic layer deposited HfO2 as insulating layer. A tunneling-based model is proposed to reproduce the experimental results, obtaining fair agreement between experiments and simulations. From the fitting procedure, a band of defects is identified, located in the first 1.7nm from the Si/HfO2 interface at an energy level E t =1.59eV below the HfO2 conduction band edge with density N t =1.36x10¹⁹ cm⁻³. A simplified analytical version of the model is proposed in order to ease the fitting procedure for the low applied voltage case considered in this work.