Pattern Formation in Globally Coupled Electrochemical Systems with an S-Shaped Current-Potential Curve

Krischer, Katharina; Mazouz, and Nadia; Flätgen, Georg

doi:10.1021/jp000548s

Cited by 55 publications

(44 citation statements)

References 42 publications

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“…The combination of S-NDR with a distributed electrical potential due to ohmic effects enables the system to globally bifurcate into active and passive regions that should correspond to the development of standing Turing-like patterns on the electrode surface. [26][27][28] Indeed, examination of the planar electrode surface following a voltammetric sweep in the presence of 60 μmol/L suppressor (Fig. 5) reveals the presence of spatially defined active and passive states on the electrode surface as shown in Fig.…”

Section: Mol/l Cusomentioning

confidence: 99%

Extreme Bottom-Up Superfilling of Through-Silicon-Vias by Damascene Processing: Suppressor Disruption, Positive Feedback and Turing Patterns

Moffat

Josell

2012

J. Electrochem. Soc.

191

269

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Extreme bottom-up copper superfilling of through-silicon-vias (TSV) is demonstrated using a CuSO 4 -H 2 SO 4 electroplating bath containing chloride and a polyether suppressor. Via filling occurs almost exclusively by deposition on the bottom via surface. The differential between the incoming fluxes of hydrated metal cations and larger suppressor molecules is accentuated by the recessed via geometry and accounts for preferential metal deposition initiating and growing from the bottom surface. The bottom-up growth front eventually propagates beyond the via opening and a substantial overburden develops. Feature filling is enhanced in electrolytes with a high [Cu 2+ ]/[H 3 O + ] ratio where global coupling by migration helps sustain the flux of Cu 2+ to actively growing surface sections. Bottom-up superfilling relies on positive feedback whereby inhibition provided by adsorption of the polyether additive on the chloride saturated surface is disrupted by the metal deposition reaction. Release of the water of hydration that accompanies reduction of the Cu 2+ aquo complex contributes to the sustained disruption of suppressor activity at the growth front. The correlation between TSV superfilling and additive-generated voltammetric hysteresis on planar substrates, which also involves a negativedifferential-resistance (S-NDR) coupled with the electrolyte resistance, provides a general framework for understanding and guiding optimization of the bottom-up growth mode in recessed surface features.Significant effort is presently focused on the development and optimization of economical processes for building three-dimensional microelectronic circuitry of arbitrary complexity. 1 Structures of interest range from deep sub-100 nm interconnects between individual transistors to micrometer scale through-silicon-vias (TSV) that serve as major electrical conduits in stacked chip arrays. The densification associated with three dimensional structures enabled by TSV in particular promises to enhance performance and functionality in emerging electronic devices. Superconformal copper electrodeposition is a key process used in the fabrication of all interconnects; the need for robust, void-free filling of ever higher aspect ratio, recessed features with reduced fill times and low cost remains an on-going challenge. Likewise, exploration of different TSV dimensions and geometries is central to understanding the reliability and extendability of Cu interconnect technology. [2][3][4][5] Both two 6 (suppressor-accelerator) and three 7 (suppressoraccelerator-leveler) additive component chemistries previously used for on-chip Damascene metallization [8][9][10][11][12] have been shown to be viable for TSV filling. Herein we show that bottom-up TSV filling may also be accomplished using a single component polyether suppressor chemistry. The polyether suppressor additive blocks metal deposition on the free surface and via side walls while rapid Cu deposition proceeds almost exclusively from the bottom surface, giving rise to bottom-up superfilling....

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Section: Mol/l Cusomentioning

confidence: 99%

Extreme Bottom-Up Superfilling of Through-Silicon-Vias by Damascene Processing: Suppressor Disruption, Positive Feedback and Turing Patterns

Moffat

Josell

2012

J. Electrochem. Soc.

191

269

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“…It has been shown that in electrical and electrochemical systems multiplicities and oscillations can be caused by a negative differential resistance, i.e. by an electrical resistance decreasing with increasing current [3][4][5]. This property is found for quite different physical systems like gas discharge systems [6] or semiconductor devices [7,8], and for various electrochemical reactions like the electro-oxidation of CO [9] or H 2 [10].…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigation of steady state multiplicities in solid oxide fuel cells*

2005

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The nonlinear steady state behaviour of solid oxide fuel cells (SOFCs) is investigated. It is found that the temperature dependence of the electrolyte conductivity has a very strong influence on the occurrence of multiple steady states, instabilities and the formation of hot spots. Two correlations from the literature for the electrolyte conductivity are studied in a lumped model and in a 1D spatially distributed model of a SOFC. The cases of galvanostatic operation, potentiostatic operation, and operation under a constant ohmic load are considered. The lumped model possesses a unique steady state under galvanostatic operation and up to three steady states under potentiostatic operation or under constant load. In the distributed model, three steady states may coexist under galvanostatic operation and up to five under potentiostatic operation. List of Symbols Bwidth of cell (m) c P molar heat capacity (J mol )1 K )1 ) C SE coefficient in Equation (24) Greek symbols a heat transfer coefficient (W m )2 K )1 ) b 1/2 coefficients in Equation (23) c pre-exponential kinetic factor (A m )2 ) g overpotential (V) h charge transfer coefficient k heat conductivity of the solid (W m )1 K )1 ) m stoichiometric coefficient q resistivity (W m) q S density of the solid (kg m )3 ) F electrical potential (V)

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“…Furthermore, global coupling is routinely present in electrochemical experiments and could play a stabilizing or destabilizing role in the dynamics, acting as an activator as well as an inhibitor, depending on the electrochemical reaction under consideration [39]. The strength of this global coupling may be readily varied, since it is introduced by an external control circuit [40].…”

Section: An Intelligent Electrochemical Platformmentioning

confidence: 99%

Electrochemistry, Emergent Patterns, and Inorganic Intelligent Response

Sadeghi¹,

Thompson²

2012

Molecular and Supramolecular Information Processing

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Pattern Formation in Globally Coupled Electrochemical Systems with an S-Shaped Current-Potential Curve

Cited by 55 publications

References 42 publications

Extreme Bottom-Up Superfilling of Through-Silicon-Vias by Damascene Processing: Suppressor Disruption, Positive Feedback and Turing Patterns

Extreme Bottom-Up Superfilling of Through-Silicon-Vias by Damascene Processing: Suppressor Disruption, Positive Feedback and Turing Patterns

Theoretical investigation of steady state multiplicities in solid oxide fuel cells*

Electrochemistry, Emergent Patterns, and Inorganic Intelligent Response

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