Viscoelastic stress relaxation in film/substrate systems—Kelvin model

Ko, Sun–Chien; Lee, Sanboh; Hsueh, Chun‐Hway

doi:10.1063/1.1541108

Cited by 17 publications

(4 citation statements)

References 20 publications

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“…Deborah number (De) was then introduced to investigate the generation of heterogeneity in xerogels, in which both the relaxation time and interaction time was identi ed: De = τ / t int (2) where τ is the relaxation time and t int is the interaction time 38 . The Voigt-Kelvin model was used to describe the stress relaxation behaviors of polymer networks and the τ was obtained from tted results (Fig S12) 39,40 . In combination with the distinct distributions of RH and water contents during the formation of xerogel bers, we comprehensively compared the stress relaxation behaviors in inner part and outer part (Fig.…”

Section: Resultsmentioning

confidence: 99%

Deborah number-dependent transition from homogeneity to heterogeneity

Xu¹,

Yang

Emmerich

et al. 2023

Preprint

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Heterogeneous structures are ubiquitous in natural organisms. Native heterogeneous structures inspire many artificial structures that are playing important roles in modern society, while it is challenging to identify the relevant factors in forming these structures due to the complexity of living systems. Here, hybrid hydrogels consisting of flexible polymer networks with embedded stiff cellulose nanocrystals (CNCs) are considered as an open system to simulate the generalized formation of heterogeneous core-sheath structures, which are formed as the dynamic response to external environment. As the result of environmental adaption during modified air drying processes of hybrid hydrogels, the formation of heterogeneous core-sheath structure was found to be correlated to the relative evaporation speed. The formation of such heterogeneity in xerogel fibers was found to be correlated with Deborah number (De). During the transition of De from large to small values with accompanying morphologies, the turning point was around De = 1. The mechanism can be considered a relative humidity-dependent glass transition behavior. These unique heterogeneous structures play a key role in tuning water permeation and water sorption capacity. Insights into these aspects can prospectively contribute to a better understanding of the native heterogeneous structures for bionics design.

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Section: Resultsmentioning

confidence: 99%

Deborah number-dependent transition from homogeneity to heterogeneity

Xu¹,

Yang

Emmerich

et al. 2023

Preprint

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show abstract

“…The Voigt-Kelvin model was used to describe the stress relaxation behaviors of polymer networks, and the τ was obtained from fitted results (Supplementary Fig. 18 ) 44 , 45 . In combination with the distinct distributions of RH and water contents during the formation of xerogel fibers, we comprehensively compared the stress relaxation behaviors in the inner part and outer part (Fig.…”

Section: Resultsmentioning

confidence: 99%

Divergent Deborah number-dependent transition from homogeneity to heterogeneity

Xu,

Yang,

Emmerich

et al. 2023

Nat Commun

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Heterogeneous structures are ubiquitous in natural organisms. Native heterogeneous structures inspire many artificial structures that are playing important roles in modern society, while it is challenging to identify the relevant factors in forming these structures due to the complexity of living systems. Here, hybrid hydrogels consisting of flexible polymer networks with embedded stiff cellulose nanocrystals (CNCs) are considered an open system to simulate the generalized formation of heterogeneous core-sheath structures. As the result of the modified air drying process of hybrid hydrogels, the formation of heterogeneous core-sheath structure is found to be correlated to the relative evaporation speed. Specifically, the formation of such heterogeneity in xerogel fibers is found to be correlated with the divergence of Deborah number (De). During the transition of De from large to small values with accompanying morphologies, the turning point is around De = 1. The mechanism can be considered a relative humidity-dependent glass transition behavior. These unique heterogeneous structures play a key role in tuning water permeation and water sorption capacity. Insights into these aspects can prospectively contribute to a better understanding of the native heterogeneous structures for bionics design.

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“…The amorphous dielectric films such as SiO 2 can exhibit a viscoelastic behavior. [26][27][28] Above the glass transition temperature, the viscosity of SiO 2 can decrease substantially, and stress relief can occur by shear flow. Thus, when wet oxidation is carried out at 1000°C, the oxide is stress-free after oxidation.…”

Section: Resultsmentioning

confidence: 99%

Effect of Viscoelastic Relaxation on Stress Memorization in Strained Silicon n MOSFETs

Gong¹,

Ng²,

Wong³

2009

J. Electrochem. Soc.

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Results from process simulations of the stress memorization technique (SMT) for nanoscale n-channel metal-oxide-semiconductor field effect transistors (n MOSFETs) are presented. The spatial distribution of stress components within the device was computed for (i) different germanium doses in the preamorphization implant step, (ii) different peak anneal temperatures in spike annealing, and (iii) different tensile stresses of the capping layer. The effect of the dielectric spacer is considered. During the spike anneal, stress is enhanced in the dielectric spacer due to the viscoelastic relaxation of the capping layer. The stress induced in the channel by the spacer and polysilicon after capping layer etch is nonuniform with maxima near the edges of the gate. Supplementary micro-Raman measurements of SMT test structures and electrical measurements of fabricated SMT devices are consistent with the simulation results.

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Viscoelastic stress relaxation in film/substrate systems—Kelvin model

Cited by 17 publications

References 20 publications

Deborah number-dependent transition from homogeneity to heterogeneity

Deborah number-dependent transition from homogeneity to heterogeneity

Divergent Deborah number-dependent transition from homogeneity to heterogeneity

Effect of Viscoelastic Relaxation on Stress Memorization in Strained Silicon n MOSFETs

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