Area-Selective Atomic Layer Deposition of ZnO by Area Activation Using Electron Beam-Induced Deposition

Mameli, Alfredo; Karasulu, Bora; Verheijen, Marcel A.; Campo, Beatriz Barcones; Macco, Bart; Mackus, Adriaan J. M.; Kessels, Erwin; Roozeboom, F.

doi:10.1021/acs.chemmater.8b03165

Cited by 74 publications

(73 citation statements)

References 44 publications

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“…2 Kessels et al have incorporated area selective ALD approaches that use organic inhibitors with ALD precursors 38 , surface activation via reactive plasma micro patterning 39 and tuning the oxygen ALD cycle exposure to selectively nucleate platinum on wafer regions 40 . The research extends to area-selective ALD on graphene surfaces (resist free) 41 and ASD of ZnO by area activation using electron beam-induced deposition 42 . Mackus et al utilized several ASD approaches combined with ALD.…”

Section: Introductionmentioning

confidence: 93%

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO₂ Thin Films by Vapor-Phase Infiltration

et al. 2020

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We describe a versatile bottom-up approach to covalently and rapidly graft hydroxyl terminated poly (2-vinyl pyridine) (P2VP-OH) polymers in 60 seconds that can subsequently be used to fabricate high quality TiO2 films on silicon substrates. A facile strategy based upon room temperature titanium vapor phase infiltration of the grafted P2VP-OH polymer brushes produces TiO2 nanofilms of 2-4 nm thickness. In order to fabricate coherent inorganic films with precise thickness control, it is critical to generate a high-quality polymer brush film i.e. a complete monolayer. Definition of precise and regular polymer monolayers is straightforwardly achieved for polymers which are weakly interacting with one another and the substrate (apart from the reactive terminal group used for grafting). However this is much more challenging for reactive systems. Crucial parameters are explored including molecular weight and solution concentration for grafting dense P2VP-OH monolayers from the liquid phase with very high coverage and uniformity across wafer scale areas. Additionally, we compare the P2VP-OH polymer system with another reactive polymer PMMA-OH and a relatively non-reactive polymer PS-OH, the latter we prove to be extremely effective for surface blocking and deactivation. Our methodology provides new insight into the grafting of polymer brushes and their ability to form dense TiO2 films. We believe the results described herein are important for further expanding the use of reactive and unreactive polymers for fields including area selective deposition, solar cell absorber layers and antimicrobial surface coatings.

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Section: Introductionmentioning

confidence: 93%

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO₂ Thin Films by Vapor-Phase Infiltration

et al. 2020

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“…24 This is illustrated by the area-selective growth of ZnO on −OH-terminated SiO 2 versus −H-terminated Si; it turns out that the precursor does not chemisorb on the −H-terminated surface but does readily react with the −OH groups, leading to selective deposition of ZnO. 25 The initial growth also plays a key role in the synthesis of 2D transition-metal dichalcogenides (TMDs) by ALD. Single and few atomic-layer thick films of these TMDs—grown by only 10 s of ALD cycles—are of interest because of their unique thickness-dependent properties.…”

Section: Introductionmentioning

confidence: 99%

Initial Growth Study of Atomic-Layer Deposition of Al₂O₃ by Vibrational Sum-Frequency Generation

Vandalon

Kessels

2019

Langmuir

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The initial growth during the atomic-layer deposition (ALD) of Al 2 O 3 using trimethylaluminum (TMA) and water was studied on two starting surfaces: SiO 2 and −H-terminated Si(111) [H/Si(111)]. In situ spectroscopy ellipsometry (SE) showed virtually immediate growth of Al 2 O 3 on both surfaces, although for H/Si(111) a reduced growth-per-cycle was observed in the initial 20 cycles. The underlying surface chemistry during the initial cycles of ALD was monitored with in situ broadband sum-frequency generation (BB-SFG) spectroscopy. For the SiO 2 surface, the −CH 3 surface groups were followed revealing that only the first TMA half-cycle deviates from the steady-growth regime. The reaction cross section of the initial TMA half-cycle (σ TMA = 2.0 ± 0.2 × 10 –18 cm 2 ) was a factor of 3 lower than the cross section of the TMA half-cycle during the steady-growth regime of ALD (σ TMA = 6.5 ± 0.6 × 10 –18 cm 2 ). All H 2 O half-cycles, including the first, showed steady-growth behavior with a corresponding reaction cross section (σ H 2 O = 4.0 ± 0.4 × 10 –20 cm 2 ). Therefore, only the first ALD cycle was affected by initial growth effects on the SiO 2 starting surface, in line with the SE data. For the H/Si(111) surface, the Si–H groups were monitored with BB-SFG spectroscopy, revealing a reaction cross section of σ TMA = 3.1 ± 0.3 × 10 –18 cm 2 for the first TMA half-cycle on H/Si(111); a factor two lower than that during the steady regime of Al 2 O 3 . These results demonstrate that the chemistry during the initial growth regime of Al 2 O 3 ALD on SiO 2 and H/Si(111) shows subtle but measurable differences compared to the steady-growth regime.

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“…1. For both cases a linear growth as well as a slight growth delay is observed: The linear fits cross the abscissa at around 4 cycles for the series on c-Si and at 7 cycles on a-Si:H. For the i-aSi:H substrate, this delay is possibly higher due to the surface passivation with silicon-hydrogen bonds, which hinders the nucleation of an MgO layer at the i-aSi:H surface during the first cycles of the deposition process [27], [28].…”

Section: Resultsmentioning

confidence: 93%

Low-Temperature Atomic Layer Deposited Magnesium Oxide as a Passivating Electron Contact for c-Si-Based Solar Cells

Chistiakova

Macco

Korte

2020

IEEE J. Photovoltaics

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In this work, we explore magnesium oxide (MgO) as electron-selective contact layer in silicon heterojunction solar cells. We report on the successful deposition of MgO layers by atomic layer deposition (ALD) at low temperatures ≤200 °C using Bis(ethylcyclopentadienyl)magnesium (Mg(CpEt)2 and H2O as precursors. Depositions were carried out on bare c-Si wafers and c-Si wafers with an intrinsic amorphous hydrogenated silicon (i-aSi:H) passivation layer. The resulting interfacial properties, surface passivation quality and contact resistivity were investigated. Upon initial deposition of MgO on an i-aSi:H/c-Si stack, the c-Si surface passivation degrades drastically. However, with an additional annealing step of 5 minutes at 200-250 °C it is possible to reverse the degradation and even to achieve charge carrier lifetimes in excess of those achieved with an i-aSi:H alone. Furthermore, we show that MgO forms an Ohmic contact with both MgO/i-aSi:H/c-Si and MgO/c-Si stacks, and we demonstrate solar cells using both types of stacks as electron contact layers.

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Area-Selective Atomic Layer Deposition of ZnO by Area Activation Using Electron Beam-Induced Deposition

Cited by 74 publications

References 44 publications

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO₂ Thin Films by Vapor-Phase Infiltration

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO₂ Thin Films by Vapor-Phase Infiltration

Initial Growth Study of Atomic-Layer Deposition of Al₂O₃ by Vibrational Sum-Frequency Generation

Low-Temperature Atomic Layer Deposited Magnesium Oxide as a Passivating Electron Contact for c-Si-Based Solar Cells

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Area-Selective Atomic Layer Deposition of ZnO by Area Activation Using Electron Beam-Induced Deposition

Cited by 74 publications

References 44 publications

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO2 Thin Films by Vapor-Phase Infiltration

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO2 Thin Films by Vapor-Phase Infiltration

Initial Growth Study of Atomic-Layer Deposition of Al2O3 by Vibrational Sum-Frequency Generation

Low-Temperature Atomic Layer Deposited Magnesium Oxide as a Passivating Electron Contact for c-Si-Based Solar Cells

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Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO₂ Thin Films by Vapor-Phase Infiltration

Precise Definition of a “Monolayer Point” in Polymer Brush Films for Fabricating Highly Coherent TiO₂ Thin Films by Vapor-Phase Infiltration

Initial Growth Study of Atomic-Layer Deposition of Al₂O₃ by Vibrational Sum-Frequency Generation