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

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] ; ; ; ; ; ;  [3]
  1. Department of Materials Engineering, KU Leuven, 3000 Leuven (Belgium)
  2. (Belgium)
  3. Imec, Kapeldreef 75, 3001 Leuven (Belgium)
Publication Date:
OSTI Identifier:
22413092
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
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