Multiscale computational fluid dynamics modeling of thermal atomic layer etching: Application to chamber configuration design

Yun, Sun-Gil; Tom, Matthew; Ou, Feiyang; Orkoulas, Gerassimos; Christofides, Panagiotis D.

doi:10.1016/j.compchemeng.2022.107757

Cited by 14 publications

(6 citation statements)

References 17 publications

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“…Typically, an ALD feeding system is equipped with four 28 or six 15 precursor containers to meet the requirements of depositing different films while reducing the replacement of the precursor container. A question may be raised: whether the position of the precursor container matters in the precursor delivery within such kind of feeding system.…”

Section: Precursorsmentioning

confidence: 99%

CFD Simulation of the Dosing Behavior within the Atomic Layer Deposition Feeding System

Yuan

Ping

Lee

et al. 2023

Ind. Eng. Chem. Res.

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The effective operation of atomic layer deposition (ALD) feeding system is the premise of realizing specific ALD processes. In the present work, a detailed computational fluid dynamics (CFD) model of the feeding system has been developed and validated, which accounts for the roles of ALD valves and manifolds. A numerical simulation of the compressible fluid flow and heat/mass transfer within the feeding system was conducted. The dosing amounts and the spatiotemporal distributions of the precursors can be accurately predicted using the CFD model, as validated by experimental results. Different precursors, operating conditions, and structures of the feeding system were simulated and analyzed to examine the operating flexibility of the feeding system. The simulation results can be adopted as the upstream boundary conditions for simulations of the ALD process in the reaction chamber. The substrate-scale simulation indicates that the effect of the feeding system on the film deposition is highly related to the surface kinetics of ALD. The present work can serve as a guide for the development and optimization of different ALD-based processes via proper operation and even the design of the feeding system.

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Section: Precursorsmentioning

confidence: 99%

CFD Simulation of the Dosing Behavior within the Atomic Layer Deposition Feeding System

Yuan

Ping

Lee

et al. 2023

Ind. Eng. Chem. Res.

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“…During the ALD process, the two gaseous precursor molecules are alternately chemisorbed on the substrate and undergo surface reactions to achieve the deposition of the film. , Thus, the surface hydroxyl coverage plays an important role in regulating the chemisorption strength and chemical reaction rate of the precursors. The gas flow pattern and heat-transfer rate in the ALD reactor affect the coverage of hydroxyl on the substrate surface, which affects the uniformity of the deposited film. − To prepare large-area ALD films, batch ALD reactors with a multi-wafer configuration are usually adopted to provide higher throughput of thin films with minimized costs. , However, this reactor structure makes it a challenge to obtain uniform film deposition, as the gas flow pattern and heat transfer inside the chamber becomes sophisticated and compromises the surface site saturation status of the substrate …”

Section: Introductionmentioning

confidence: 99%

“…As a consequence, the parameters of batch ALD reactors have been extensively studied for optimization, − including the internal precursor concentration distribution, wafer arrangement, and the design of various gas delivery structures (such as, multi-inlet, multi-outlet). Pan et al presented computational fluid dynamics (CFD) models combined with experiments to investigate the gas flow in a multi-wafer ALD reactor with vertical and horizontal arrangements of wafers.…”

Section: Introductionmentioning

confidence: 99%

“…However, when scaling up the pancake-type cross-flow reactor, the uniformity of flow pattern may largely deteriorate as the flow may create short circuit paths across the axis with recirculation zones on the sides. Perforated plates and other multi-nozzle configurations have been reported to improve the uniformity of gas flow in the chamber using CFD models, which elegantly established the optimal pulse and purge durations to enhance the deposition efficiency. , However, the volume of this reactor was not large enough and enlarging these gas distribution configurations may increase the surface area of the chamber with additional adsorption of precursors, hindering the fast switching of precursor gas flows. A diagonal baffle has been reported that enables a region of uniform flow in the center of the cross-flow chamber.…”

Section: Introductionmentioning

confidence: 99%

“…The regulation of the flow pattern requires control of the entrance mode of the carrier gas into the ALD chamber. , In general, gas delivery using a conventional showerhead structure allows the gas inlet direction to be perpendicular to the substrate surface . As a result, the gas is injected uniformly over the entire substrate surface and all parts of the substrate are exposed to the fresh precursor simultaneously, resulting in uniform heat and mass transfer over the substrate surface and a uniform film growth rate.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Scaling-Up of Thin-Film Photoelectrodes for Solar Water Splitting Based on Atomic Layer Deposition

Wang

Zhang

Liu

et al. 2022

ACS Appl. Mater. Interfaces

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Atomic layer deposition (ALD) is an established method to prepare protective layers for Si-based photoelectrodes for photoelectrochemical (PEC) water splitting. Although ALD has been widely used in microelectronics and photovoltaics, it remains a great challenge to design simple and effective ALD systems to deposit large and uniform protective films for Si-based photoelectrodes with industrial sizes. This paper describes the design and realization of a simple ALD chamber configuration for photoelectrodes with large sizes, in which the influence of a gas redistributor over the gas flow and heat transfer during film growth was revealed by computational fluid dynamics simulations and experimental investigations. A simple circular baffle-type redistributor was proposed to establish a uniform gas flow field throughout the ALD reactor, resulting in a uniform temperature profile. With this simple baffle redistributor, the large-area Al2O3 monitor film (46 nm thickness) reached a good nonuniformity (Nu %) of 0.88% over a large area of 256 cm2. This design enables the fabrication of large-scale photocathodes from standard industrial-grade 166 mm Si(100) wafers (276 cm2) by depositing 50 nm TiO2 protective films with Nu % less than 5%. The obtained photocathode achieves a saturation current of 6.45 A with a hydrogen production rate of 43.2 mL/min under outdoor illumination. This work elucidates how flow pattern and heat transfer may influence the deposition of protective layers over large photoelectrodes, providing guidance for future industrial applications of PEC water splitting.

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Multivariable run-to-run control of thermal atomic layer etching of aluminum oxide thin films

Yun

Tom

et al. 2022

Chemical Engineering Research and Design

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Multiscale computational fluid dynamics modeling of thermal atomic layer etching: Application to chamber configuration design

Cited by 14 publications

References 17 publications

CFD Simulation of the Dosing Behavior within the Atomic Layer Deposition Feeding System

CFD Simulation of the Dosing Behavior within the Atomic Layer Deposition Feeding System

Scaling-Up of Thin-Film Photoelectrodes for Solar Water Splitting Based on Atomic Layer Deposition

Multivariable run-to-run control of thermal atomic layer etching of aluminum oxide thin films

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