Blocking mechanisms in area-selective ALD by small molecule inhibitors of different sizes: Steric shielding versus chemical passivation

Yu, Pengmei; Merkx, Marc J.M.; Tezsevin, Ilker; Lemaire, Paul C.; Hausmann, Dennis M.; Sandoval, Tania E.; Kessels, Wilhelmus M.M.; Mackus, Adriaan J.M.

doi:10.1016/j.apsusc.2024.160141

Cited by 7 publications

(3 citation statements)

References 60 publications

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“…One strategy shown by Mackus et al in the past was to add a second, smaller SMI to increase the Si–OH coverage and SMI density. ,, As TMPS is itself too bulky to block O2, whether the pulsing of another, smaller SMI could be advantageous was tested. Panels c and d of Figure show the PS and SB state of O2 on A.1-O:13/56/4 for the monofunctional methoxytrimethylsilane (MTMS) inhibitor.…”

Section: Results and Discussionmentioning

confidence: 99%

An Atomistic Picture of Buildup and Degradation Reactions in Area-Selective Atomic Layer Deposition with a Small Molecule Inhibitor

Wellmann,

Pieck,

Tonner-Zech

2024

Chem. Mater.

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We investigate the blocking layer formation of the trimethoxypropylsilane small molecule inhibitor (SMI), its blocking mechanisms, and all relevant blocking layer disintegration reactions on SiO 2 in the area-selective atomic layer deposition of Al 2 O 3 with density functional theory-based methods. The choice of amorphous silica (a-SiO 2 ) surface models proves to be essential for obtaining the correct SMI chemistry. We demonstrate that complete blocking of reactive sites is possible here and deduce an upper SMI density limit of the resulting blocking layer that is limited by Pauli repulsion. The SMI adsorption process can nevertheless leave unreacted silanol groups, which could be remedied by using a second monodentate SMI. The SMI layer is inert against neither common aluminum precursors nor the co-reactant water as our comprehensive analysis of the various blocking layer disintegration reactions for different SMI layer densities shows. We report a new blocking mechanism of the SMI layer and propose to differentiate what is discussed as the "steric blocking" effect into the known "adsorption prevention" effect and the newly found "reactivity reduction" effect. For trimethylaluminum (TMA), an additional favorable SMI layer decomposition mechanism is found compared to that of the bulkier triethylaluminum (TEA), which could explain the lower selectivity of TMA found experimentally. Our computational work offers some principles and ideas for future experiments to improve selectivity in area-selective atomic layer deposition processes.

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Section: Results and Discussionmentioning

confidence: 99%

An Atomistic Picture of Buildup and Degradation Reactions in Area-Selective Atomic Layer Deposition with a Small Molecule Inhibitor

Wellmann,

Pieck,

Tonner-Zech

2024

Chem. Mater.

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“…RSA of different shapes/substances has been a topic of interest in different fields from physical chemistry and biology to the car parking problem. − In order to study these various phenomena, different types of RSA simulation methods were developed considering continuum, or lattice-based approaches in one-dimensional, two-dimensional, and three-dimensional models . More specifically, the two-dimensional lattice RSA simulations have been used for the investigation of the packing of small molecule inhibitors (SMIs) during area-selective ALD. ,,, By enabling the evaluation of the SMI packing and the precursor-blocking performance of the SMIs, these applications showed the potential of RSA simulations for the ALD field.…”

mentioning

confidence: 99%

“… 28 More specifically, the two-dimensional lattice RSA simulations have been used for the investigation of the packing of small molecule inhibitors (SMIs) during area-selective ALD. 19 , 20 , 29 , 30 By enabling the evaluation of the SMI packing and the precursor-blocking performance of the SMIs, these applications showed the potential of RSA simulations for the ALD field.…”

mentioning

confidence: 99%

The Consequences of Random Sequential Adsorption for the Precursor Packing and Growth-Per-Cycle of Atomic Layer Deposition Processes

Tezsevin,

Deijkers,

Merkx

et al. 2024

J. Phys. Chem. Lett.

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Atomic layer deposition (ALD) processes are known to deposit submonolayers of material per cycle, primarily attributed to steric hindrance and a limited number of surface sites. However, an often-overlooked factor is the random sequential adsorption (RSA) mechanism, where precursor molecules arrive one-by-one and adsorb at random surface sites. Consequently, the saturation coverage of precursors significantly deviates from ideal closed packing. In this study, we investigated the influence of RSA on precursor adsorption saturation and, consequently, on the growth per cycle (GPC) of the ALD processes. Our simulations revealed that the RSA model leads to a 22% to 40% lower surface density compared to the reference case of ordered packing. Furthermore, based on the precursor shape and size, we estimated GPC values with an average accuracy of 0.05 Å relative to experimental literature data. This work shows the critical role of RSA in ALD, emphasizing the need to consider this mechanism for a more accurate process design and optimization.

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Role of Molecular Orientation: Comparison of Nitrogenous Aromatic Small Molecule Inhibitors for Area-Selective Atomic Layer Deposition

Shearer,

Pieck,

Yarbrough

et al. 2024

Chem. Mater.

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Blocking mechanisms in area-selective ALD by small molecule inhibitors of different sizes: Steric shielding versus chemical passivation

Cited by 7 publications

References 60 publications

An Atomistic Picture of Buildup and Degradation Reactions in Area-Selective Atomic Layer Deposition with a Small Molecule Inhibitor

An Atomistic Picture of Buildup and Degradation Reactions in Area-Selective Atomic Layer Deposition with a Small Molecule Inhibitor

The Consequences of Random Sequential Adsorption for the Precursor Packing and Growth-Per-Cycle of Atomic Layer Deposition Processes

Role of Molecular Orientation: Comparison of Nitrogenous Aromatic Small Molecule Inhibitors for Area-Selective Atomic Layer Deposition

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