Atomic Layer Deposition and Vapor Phase Infiltration

Losego, Mark D.; Peng, Qing

doi:10.1002/9783527819249.ch5

Cited by 12 publications

(11 citation statements)

References 92 publications

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“…Vapor-phase infiltration (VPI) exposes organic polymers to vapor-phase metal-organic precursors that sorb and diffuse throughout the polymer, eventually becoming entrapped (through reaction or loss of volatility), thus creating an organic–inorganic hybrid material. − After exposure to the metal-organic precursor, a second, vapor-phase coreactant (e.g., water vapor or oxygen) is delivered to react with the precursor inside of the polymer to produce a final inorganic product that is stable in ambient atmosphere. These hybrid materials have demonstrated a variety of commercially and industrially relevant properties such as increased electrical conductivity, − solvent stability, , photoluminescence and color change, − and enhanced mechanical properties. − Additionally, VPI can be leveraged to create high-fidelity inorganic nanostructures often from sacrificial copolymer templates − and to selectively image polymer phases in polymeric mixtures or polymer morphology with electron microscopy. − Critically, VPI is capable of forming these hybrid materials across numerous length scales and without significantly modifying the original polymer’s macroscale form or microstructure. ,, As a result, VPI has been applied in a wide variety of fields, from polymer membranes for chemical separations to photovoltaics, catalysis, triboelectricity, gas sensing, and more.…”

Section: Introductionmentioning

confidence: 99%

Reaction–Diffusion Transport Model to Predict Precursor Uptake and Spatial Distribution in Vapor-Phase Infiltration Processes

et al. 2021

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Vapor-phase infiltration (VPI) has emerged as a scalable process for transforming polymer products into a variety of organic−inorganic hybrid materials with potential applications to a number of commercial industries. However, the fundamental transport kinetics of VPI are still not well understood. Most explorations to date have relied on simple Fickian diffusion models for VPI transport. However, these Fickian diffusion models often fail to entirely capture the physical phenomena of VPI because of the complex convolution of diffusion and reaction processes. In this work, a reaction−diffusion model is developed that provides additional insight into how the presence of reactions between polymers and metal-organic precursors modifies the transport behavior of the metal-organic VPI precursor through the infiltrated polymer. From this model, parameters such as the second-order rate constant for the reaction between the precursor and polymer and a diffusive hindering factor can be extracted. The model is shown to both fit well to physical measurements and, more critically, predict experimental outcomes. Additionally, nondimensionalization is employed to create domain maps based on a wide variety of VPI parameters. The resulting domain maps showcase the breadth of behaviors captured by this reaction−diffusion model for VPI.

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Section: Introductionmentioning

confidence: 99%

Reaction–Diffusion Transport Model to Predict Precursor Uptake and Spatial Distribution in Vapor-Phase Infiltration Processes

et al. 2021

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“…Previous research has shown that surface functionalization of the substrate prior to ALD deposition provides (additional) reactive sites during ALD nucleation [44][45][46][47][48][49]. The HAADF-STEM cross-section analysis revealed that no sub-surface growth occurred as pristine BPDA-PPD polyimide has reactive groups available for the nucleation of Al2O3 and HfO2.…”

Section: Influence Of Plasma Activation On the Ald Nucleationmentioning

confidence: 94%

“…However, ALD precursor molecules can dissolve and/or diffuse into the polymer leading to subsurface growth of the ALD material. This type of growth, when promoted by the conditions of the deposition process and favored by the type of polymer, produces organic/inorganic hybrid subsurface layers and falls into the category of so-called sequential infiltration synthesis (SIS), sequential vapor infiltration (SVI), vapor phase infiltration (VPI), or multiple pulsed vapor phase infiltration (MPI) [49][50][51]. On the other hand, for polymers with functional groups inherently present in their chemical structure and available at the surface, the ALD nucleation and growth mostly occurs at the surface, obtaining an ALD film on top of the polymer and a distinct interface between both materials.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Nucleation of AlOx and HfOx ALD on Polyimide: Influence of Plasma Activation

et al. 2021

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There is an increasing interest in atomic layer deposition (ALD) on polymers for the development of membranes, electronics, (3D) nanostructures and specially for the development of hermetic packaging of the new generation of flexible implantable micro-devices. This evolution demands a better understanding of the ALD nucleation process on polymers, which has not been reported in a visual way. Herein, a visual study of ALD nucleation on polymers is presented, based on the different dry etching speeds between polymers (fast) and metal oxides (slow). An etching process removes the polyimide with the nucleating ALD acting as a mask, making the nucleation features visible through secondary electron microscopy analyses. The nucleation of both Al2O3 and HfO2 on polyimide was investigated. Both materials followed an island-coalescence nucleation. First, local islands formed, progressively coalescing into filaments, which connected and formed meshes. These meshes evolved into porous layers that eventually grew to a full layer, marking the end of the nucleation. Cross-sections were analyzed, observing no sub-surface growth. This approach was used to evaluate the influence of plasma-activating polyimide on the nucleation. Plasma-induced oxygen functionalities provided additional surface reactive sites for the ALD precursors to adsorb and start the nucleation. The presented nucleation study proved to be a straightforward and simple way to evaluate ALD nucleation on polymers.

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“…A homogeneous growth is promoted, preventing precursor–precursor, precursor–by-product, by-product–by-product reactions [ 19 ]. Consequently, the formed coatings are very precise and controlled in a conformal configuration [ 41 ].…”

Section: Coatings On Pmma By Thermal Atomic Layer Depositionmentioning

confidence: 99%

“…A homogeneous growth is promoted, preventing precursor-precursor, precursor-by-product, by-product-by-product reactions [19]. Consequently, the formed coatings are very precise and controlled in a conformal configuration [41]. The PMMA polymer is a very stable material; in other words, inert, consisting in strong chemical bonds, which hinder the modification of the chain [42].…”

Section: Pmma Challenges For Aldmentioning

confidence: 99%

Is Poly(methyl methacrylate) (PMMA) a Suitable Substrate for ALD?: A Review

et al. 2021

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Poly (methyl methacrylate) (PMMA) is a thermoplastic synthetic polymer, which displays superior characteristics such as transparency, good tensile strength, and processability. Its performance can be improved by surface engineering via the use of functionalized thin film coatings, resulting in its versatility across a host of applications including, energy harvesting, dielectric layers and water purification. Modification of the PMMA surface can be achieved by atomic layer deposition (ALD), a vapor-phase, chemical deposition technique, which permits atomic-level control. However, PMMA presents a challenge for ALD due to its lack of active surface sites, necessary for gas precursor reaction, nucleation, and subsequent growth. The purpose of this review is to discuss the research related to the employment of PMMA as either a substrate, support, or masking layer over a range of ALD thin film growth techniques, namely, thermal, plasma-enhanced, and area-selective atomic layer deposition. It also highlights applications in the selected fields of flexible electronics, biomaterials, sensing, and photocatalysis, and underscores relevant characterization techniques. Further, it concludes with a prospective view of the role of ALD in PMMA processing.

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Atomic Layer Deposition and Vapor Phase Infiltration

Cited by 12 publications

References 92 publications

Reaction–Diffusion Transport Model to Predict Precursor Uptake and Spatial Distribution in Vapor-Phase Infiltration Processes

Reaction–Diffusion Transport Model to Predict Precursor Uptake and Spatial Distribution in Vapor-Phase Infiltration Processes

Investigating the Nucleation of AlOx and HfOx ALD on Polyimide: Influence of Plasma Activation

Is Poly(methyl methacrylate) (PMMA) a Suitable Substrate for ALD?: A Review

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