Conformality of atomic layer deposition in microchannels: impact of process parameters on the simulated thickness profile

Yim, Jihong; Verkama, Emma; Velasco, J.; Arts, Karsten; Puurunen, Riikka L.

doi:10.1039/d1cp04758b

Cited by 19 publications

(58 citation statements)

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“…Kandlikar and Grande have offered a thorough historical perspective on the evolution of microchannels and mini-channels 49) . According to current research, microchannels can be categorized based on a number of factors, including the Knudsen number (Kn) [49][50][51][52][53][54][55][56][57] . All in all, the comprehensive review works along with recent insights agree that geometry is of utmost concern in the design of microchannels in terms of controlling fluid flow parameters by modifying geometry considerations [58][59][60] .…”

Section: Classification Of Microchannelsmentioning

confidence: 99%

A Review on Microchannel Fabrication Methods and Applications in Large-Scale and Prospective Industries

Afzal¹,

Tayyaba²,

Ashraf³

et al. 2022

Evergreen

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Microchannels based on microelectromechanical systems (MEMS) have received a lot of interest in the microfluidics and biomedical fields over the past forty years. While their applications have been multifarious, a comprehensive literature review focusing on their design, type, and applications is not currently present in the literature. Researchers working on these elements of microchannels will gain targeted knowledge from the current review on microchannels. Due to its advanced properties, flexibility of mass, and small size, microdevice demand has been rising quickly, particularly in industrial applications. The classification of microchannels and their uses are the main focus of this work. These include but are not limited to molding, electroplating, lithography, lab-ona-chip, micromolding, micromachining, micromilling, laser ablation, lithography, microcontact printing (µcp), hot embossing, electrochemical micromachining (EMM), and etching. In addition, numerous hybrid techniques for microchannel manufacturing have been reported. So, in essence, this review offers a range of advancements in microchannel manufacturing. The review also attempts to present a qualitative analysis describing the various methodologies associated with microchannels in terms of their design, shape, and flow regimes for applications such as pressure drop and transfer of heat prediction. Additionally, depending on the precise uses needed, a number of materials, including but not limited to ceramics, silicon, metals, and polymers, are utilized in the manufacture of microchannels. On metallic substrates, polymers such as silicon, glass, and polymeric materials are used. The biomedical industry uses polymeric and glass substrates instead of silicon substrates, which are used for mechanical engineering and electronic applications. In addition to outlining methods for choosing the best kind of microchannel, this paper also suggests important directions for the future.

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Section: Classification Of Microchannelsmentioning

confidence: 99%

A Review on Microchannel Fabrication Methods and Applications in Large-Scale and Prospective Industries

Afzal¹,

Tayyaba²,

Ashraf³

et al. 2022

Evergreen

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“…5 However, conformality of the ALD process is not self-guaranteed, especially for coatings in high-aspect-ratio (HAR) features. 1,[6][7][8][9][10] Higher exposure is required to saturate the surface of high surface area porous supports compared to coating planar substrates. [6][7][8][10][11][12][13][14][15][16] Various experimental and modeling approaches have been developed to investigate the effect of process parameters on the conformality of ALD with HAR features.…”

mentioning

confidence: 99%

“…1,[6][7][8][9][10] Higher exposure is required to saturate the surface of high surface area porous supports compared to coating planar substrates. [6][7][8][10][11][12][13][14][15][16] Various experimental and modeling approaches have been developed to investigate the effect of process parameters on the conformality of ALD with HAR features. 1,6,7,9,10,12,15,[17][18][19][20][21][22] A recent simulation study showed that growth per cycle (GPC) and molar mass of reactant, in addition to the exposure (exposure = partial pressure × reactant pulse time), influenced the penetration depth of the ALD coating in a microchannel.…”

mentioning

confidence: 99%

“…[6][7][8][10][11][12][13][14][15][16] Various experimental and modeling approaches have been developed to investigate the effect of process parameters on the conformality of ALD with HAR features. 1,6,7,9,10,12,15,[17][18][19][20][21][22] A recent simulation study showed that growth per cycle (GPC) and molar mass of reactant, in addition to the exposure (exposure = partial pressure × reactant pulse time), influenced the penetration depth of the ALD coating in a microchannel. 10 Preparation of heterogeneous catalysts via ALD has attracted increasing global interest, as evident from recent reviews.…”

mentioning

confidence: 99%

“…1,6,7,9,10,12,15,[17][18][19][20][21][22] A recent simulation study showed that growth per cycle (GPC) and molar mass of reactant, in addition to the exposure (exposure = partial pressure × reactant pulse time), influenced the penetration depth of the ALD coating in a microchannel. 10 Preparation of heterogeneous catalysts via ALD has attracted increasing global interest, as evident from recent reviews. [23][24][25][26][27][28][29] However, the use of ALD for catalysis is not new.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Atomic layer deposition of zinc oxide on mesoporous zirconia using zinc(II) acetylacetonate and air

Yim

Haimi

Mäntymäki

et al. 2023

Preprint

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The self-terminating chemistry of atomic layer deposition (ALD) ideally enables the growth of homogeneously distributed materials on an atomic scale. This study investigates the ALD of zinc oxide (ZnO) on mesoporous zirconium oxide (ZrO2) using zinc acetylacetonate [Zn(acac)2] and synthetic air in a fixed-bed powder ALD reactor. A broad variety of methods, including thermogravimetry analysis, scanning electron microscopy with energy dispersive X-ray spectroscopy, low energy ion scattering, X-ray absorption near edge structure, X-ray photoelectron spectroscopy, in situ diffuse reflectance infrared Fourier transform spectroscopy-mass spectrometry, and density functional theory calculations were used to analyze the reactant and the resulting samples. The factors affecting the zinc loading (wt%) on ZrO2 were investigated by varying the ALD reaction temperature (160 °C–240 °C), the calcination temperature of zirconium oxide (400 °C–1000 °C) and the ALD cycle number (up to three). The studied process showed self-terminating behavior, with the areal number density of zinc of approximately two atoms per square nanometer per cycle. Zinc was distributed throughout ZrO2. After the Zn(acac)2 reaction, acac ligands were removed using synthetic air at 500 °C. In the following cycles, the already-deposited ZnO acted as nuclei for further ZnO growth. This study demonstrates the potential of Zn(acac)2 as an ALD reactant and provides an initial understanding of ZnO growth via ALD on high surface area porous particles as an example for catalytic applications.

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Enhancement of Conformality of Silicon Nitride Thin Films by ABC‐Type Atomic Layer Deposition

Kim,

Yeon,

Cho

et al. 2023

Adv Elect Materials

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Atomic layer deposition (ALD) is utilized for the fabrication of miniaturized electronic devices with nanometer‐scale features. However, the conventional ALD process on high‐aspect‐ratio (HAR) substrates often results in the deposition of thin films with suboptimal conformality over the depth of the trench structures. This study introduces an ABC‐type ALD of silicon nitride (SiNx) employing vapor‐deliverable tert‐butyl chloride (TBC) as a surface inhibitor. Herein, density functional theory (DFT) calculations elucidate the surface reaction mechanisms, confirming the inhibition of the Si precursor by the t‐butyl moiety. Notably, the ABC‐type ALD exhibits reduced growth per cycle relative to the conventional process while avoiding detectable carbon contamination in the SiNx thin films. Applying this process to substrates with trench structures revealed a substantial improvement in conformality following the introduction of TBC. Furthermore, the step coverage of the deposited SiNx can be modulated by adjusting TBC exposure, enabling greater film thickness at the bottom than that at the top of the trench. The proposed method of modulating ALD processes holds potential for the high‐volume manufacturing of semiconductor devices with HAR structures.

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Conformality of atomic layer deposition in microchannels: impact of process parameters on the simulated thickness profile

Abstract: Unparalleled conformality is driving ever new applications for atomic layer deposition (ALD), a thin film growth method based on repeated self-terminating gas-solid reactions. In this work, we re-implemented a diffusion-reaction...

Cited by 19 publications

References 52 publications

A Review on Microchannel Fabrication Methods and Applications in Large-Scale and Prospective Industries

A Review on Microchannel Fabrication Methods and Applications in Large-Scale and Prospective Industries

Atomic layer deposition of zinc oxide on mesoporous zirconia using zinc(II) acetylacetonate and air

Enhancement of Conformality of Silicon Nitride Thin Films by ABC‐Type Atomic Layer Deposition

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