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Title: Towards understanding intrinsic degradation and breakdown mechanisms in SiOCH low-k dielectrics

Abstract

The degradation and breakdown mechanisms of a SiOCH low-k material with k = 2.3 (25% porosity) and thicknesses ranging from 90 nm to 20 nm were investigated. By combining the time dependent dielectric breakdown data at positive/negative bias stress with the thickness scaling results, dielectric failure is proven to be intrinsic and not influenced by copper drift or metal barrier deposition induced dielectric damage. It is shown that stress induced leakage current (SILC) can be used as a measure of dielectric degradation. Therefore, low field lifetimes can be safely estimated using SILC extrapolation. Based on our results, both the impact damage model and the power law model have a good accuracy for low field lifetime prediction. Recovery and anneal experiments are used to study the physical nature causing the observed negative flatband voltage shifts in our metal-insulator-semiconductor planar capacitor structures, where hydrogen induced unstable fast and slow donor type interface states are hypothesized to be the root cause of the observed shifts. We suggest that atomic hydrogen is released from the dielectric during electron injection and migrates to the interfacial region. Our model is further supported by an observed irreversible SILC change during the recovery and anneal studies. The degradation mechanism proposed in thismore » work, supported by the low field lifetime data, provides a feasible explanation for intrinsic low-k dielectric failure.« less

Authors:
 [1]; ; ; ; ; ;  [2]
  1. Department of Materials Engineering, KU Leuven, 3000 Leuven (Belgium)
  2. Imec, Kapeldreef 75, 3001 Leuven (Belgium)
Publication Date:
OSTI Identifier:
22413092
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BREAKDOWN; CAPACITORS; CARBON COMPOUNDS; COPPER; DEPOSITION; DIELECTRIC MATERIALS; ELECTRIC POTENTIAL; ELECTRON BEAM INJECTION; EXTRAPOLATION; HYDROGEN COMPOUNDS; INTERFACES; LEAKAGE CURRENT; LIFETIME; SEMICONDUCTOR MATERIALS; STRESSES; TIME DEPENDENCE

Citation Formats

Wu, C., E-mail: Chen.Wu@imec.be, De Wolf, I., Imec, Kapeldreef 75, 3001 Leuven, Li, Y., Ciofi, I., Kauerauf, Th., Bömmels, J., Tőkei, Zs., and Croes, K. Towards understanding intrinsic degradation and breakdown mechanisms in SiOCH low-k dielectrics. United States: N. p., 2015. Web. doi:10.1063/1.4907686.
Wu, C., E-mail: Chen.Wu@imec.be, De Wolf, I., Imec, Kapeldreef 75, 3001 Leuven, Li, Y., Ciofi, I., Kauerauf, Th., Bömmels, J., Tőkei, Zs., & Croes, K. Towards understanding intrinsic degradation and breakdown mechanisms in SiOCH low-k dielectrics. United States. https://doi.org/10.1063/1.4907686
Wu, C., E-mail: Chen.Wu@imec.be, De Wolf, I., Imec, Kapeldreef 75, 3001 Leuven, Li, Y., Ciofi, I., Kauerauf, Th., Bömmels, J., Tőkei, Zs., and Croes, K. 2015. "Towards understanding intrinsic degradation and breakdown mechanisms in SiOCH low-k dielectrics". United States. https://doi.org/10.1063/1.4907686.
@article{osti_22413092,
title = {Towards understanding intrinsic degradation and breakdown mechanisms in SiOCH low-k dielectrics},
author = {Wu, C., E-mail: Chen.Wu@imec.be and De Wolf, I. and Imec, Kapeldreef 75, 3001 Leuven and Li, Y. and Ciofi, I. and Kauerauf, Th. and Bömmels, J. and Tőkei, Zs. and Croes, K.},
abstractNote = {The degradation and breakdown mechanisms of a SiOCH low-k material with k = 2.3 (25% porosity) and thicknesses ranging from 90 nm to 20 nm were investigated. By combining the time dependent dielectric breakdown data at positive/negative bias stress with the thickness scaling results, dielectric failure is proven to be intrinsic and not influenced by copper drift or metal barrier deposition induced dielectric damage. It is shown that stress induced leakage current (SILC) can be used as a measure of dielectric degradation. Therefore, low field lifetimes can be safely estimated using SILC extrapolation. Based on our results, both the impact damage model and the power law model have a good accuracy for low field lifetime prediction. Recovery and anneal experiments are used to study the physical nature causing the observed negative flatband voltage shifts in our metal-insulator-semiconductor planar capacitor structures, where hydrogen induced unstable fast and slow donor type interface states are hypothesized to be the root cause of the observed shifts. We suggest that atomic hydrogen is released from the dielectric during electron injection and migrates to the interfacial region. Our model is further supported by an observed irreversible SILC change during the recovery and anneal studies. The degradation mechanism proposed in this work, supported by the low field lifetime data, provides a feasible explanation for intrinsic low-k dielectric failure.},
doi = {10.1063/1.4907686},
url = {https://www.osti.gov/biblio/22413092}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 6,
volume = 117,
place = {United States},
year = {Sat Feb 14 00:00:00 EST 2015},
month = {Sat Feb 14 00:00:00 EST 2015}
}