Issue 15, 2022

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 model from the literature to simulate the propagation of film growth in wide microchannels and used that model to explore trends in both the thickness profile as a function of process parameters and different diffusion regimes. In the model, partial pressure of the ALD reactant was analytically approximated. Simulations were made as a function of kinetic and process parameters such as the temperature, (lumped) sticking coefficient, molar mass of the ALD reactant, reactant's exposure time and pressure, total pressure, density of the grown material, and growth per cycle (GPC) of the ALD process. Increasing the molar mass and the GPC, for example, resulted in a decreasing penetration depth into the microchannel. The influence of the mass and size of the inert gas molecules on the thickness profile depended on the diffusion regime (free molecular flow vs. transition flow). The modelling was compared to a recent slope method to extract the sticking coefficient. The slope method gave systematically somewhat higher sticking coefficient values compared to the input sticking coefficient values; the potential reasons behind the observed differences are discussed.

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

Supplementary files

Article information

Article type
Paper
Submitted
18 Oct 2021
Accepted
08 Mar 2022
First published
11 Mar 2022
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2022,24, 8645-8660

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

J. Yim, E. Verkama, J. A. Velasco, K. Arts and R. L. Puurunen, Phys. Chem. Chem. Phys., 2022, 24, 8645 DOI: 10.1039/D1CP04758B

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