Defect states and charge trapping characteristics of HfO2 films for high performance nonvolatile memory applications

In this work, we present significant charge trapping memory effects of the metal-hafnium oxide-SiO2-Si (MHOS) structure. The devices based on 800 °C annealed HfO2 film exhibit a large memory window of ∼5.1 V under ±10 V sweeping voltages and excellent charge retention properties with only small char...

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Bibliographic Details
Published in:Applied physics letters 2014-10, Vol.105 (17)
Main Authors: Zhang, Y., Shao, Y. Y., Lu, X. B., Zeng, M., Zhang, Z., Gao, X. S., Zhang, X. J., Liu, J.-M., Dai, J. Y.
Format: Article
Language:English
Subjects:
Applied physics
Conduction bands
Defects
Energy levels
Hafnium oxide
Photoluminescence
Random access memory
Silicon dioxide
Trapping
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Summary:In this work, we present significant charge trapping memory effects of the metal-hafnium oxide-SiO2-Si (MHOS) structure. The devices based on 800 °C annealed HfO2 film exhibit a large memory window of ∼5.1 V under ±10 V sweeping voltages and excellent charge retention properties with only small charge loss of ∼2.6% after more than 104 s retention. The outstanding memory characteristics are attributed to the high density of deep defect states in HfO2 films. We investigated the defect states in the HfO2 films by photoluminescence and photoluminescence excitation measurements and found that the defect states distributed in deep energy levels ranging from 1.1 eV to 2.9 eV below the conduction band. Our work provides further insights for the charge trapping mechanisms of the HfO2 based MHOS devices.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4900745