Publications by authors named "Adriaan J M Mackus"

13 Publications

  • Page 1 of 1

Reaction Mechanisms during Atomic Layer Deposition of AlF Using Al(CH) and SF Plasma.

J Phys Chem C Nanomater Interfaces 2021 Feb 10;125(7):3913-3923. Epub 2021 Feb 10.

Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

Metal fluorides generally demonstrate a wide band gap and a low refractive index, and they are commonly employed in optics and optoelectronics. Recently, an SF plasma was introduced as a novel co-reactant for the atomic layer deposition (ALD) of metal fluorides. In this work, the reaction mechanisms underlying the ALD of fluorides using a fluorine-containing plasma are investigated, considering aluminum fluoride (AlF) ALD from Al(CH) and an SF plasma as a model system. Surface infrared spectroscopy studies indicated that Al(CH) reacts with the surface in a ligand-exchange reaction by accepting F from the AlF film and forming CH surface groups. It was found that at low deposition temperatures Al(CH) also reacts with HF surface species. These HF species are formed during the SF plasma exposure and were detected both at the surface and in the gas phase using infrared spectroscopy and quadrupole mass spectrometry (QMS), respectively. Furthermore, QMS and optical emission spectroscopy (OES) measurements showed that CH and CH F ( ≤ 3) species are the main reaction products during the SF plasma exposure. The CH release is explained by the reaction of CH ligands with HF, while CH F species originate from the interaction of the SF plasma with CH ligands. At high temperatures, a transition from AlF deposition to AlO etching was observed using infrared spectroscopy. The obtained insights indicate a reaction pathway where F radicals from the SF plasma eliminate the CH ligands remaining after precursor dosing and where F radicals are simultaneously responsible for the fluorination reaction. The understanding of the reaction mechanisms during AlF growth can help in developing ALD processes for other metal fluorides using a fluorine-containing plasma as the co-reactant as well as atomic layer etching (ALE) processes involving surface fluorination.
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http://dx.doi.org/10.1021/acs.jpcc.0c10695DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8016095PMC
February 2021

Nanoscale Encapsulation of Perovskite Nanocrystal Luminescent Films via Plasma-Enhanced SiO Atomic Layer Deposition.

ACS Appl Mater Interfaces 2020 Nov 11;12(47):53519-53527. Epub 2020 Nov 11.

State Key Laboratory of Digital of Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074, P. R. China.

Photoluminescence perovskite nanocrystals (NCs) have shown significant potential in optoelectronic applications in view of their narrow band emission with high photoluminescence quantum yields and color tunability. The main obstacle for practical applications is to obtain high durability against an external environment. In this work, a low temperature (50 °C) plasma-enhanced atomic layer deposition (PE-ALD) protection strategy was developed to stabilize CsPbBr NCs. Silica was employed as the encapsulation layer because of its excellent light transmission performance and water corrosion resistance. The growth mechanism of inorganic SiO via PE-ALD was investigated in detail. The Si precursor bis(diethylamino)silane (BDEAS) reacted with the hydroxyl groups (-OH) and thereby initiated the subsequent silica growth while having minimal influence to the organic ligands and did not cause PL quenching. Subsequently, O plasma with high reactivity was used to oxidize the amine ligands of the BDEAS precursor while did not etch the NCs. The obtained CsPbBr NCs/SiO film exhibited exceptional stability in water, light, and heat as compared to the pristine NC film. Based on this method, a white light-emitting diode with improved operational stability was successfully fabricated, which exhibited a wide color gamut (∼126% of the National Television Standard Committee). Our work successfully demonstrates an efficient protection scheme via the PE-ALD method, which extends the applied range of other materials for stabilization of perovskite NCs through this approach.
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http://dx.doi.org/10.1021/acsami.0c16082DOI Listing
November 2020

Area-Selective Atomic Layer Deposition of Two-Dimensional WS Nanolayers.

ACS Mater Lett 2020 May 8;2(5):511-518. Epub 2020 Apr 8.

Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands.

With downscaling of device dimensions, two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) such as WS are being considered as promising materials for future applications in nanoelectronics. However, at these nanoscale regimes, incorporating TMD layers in the device architecture with precise control of critical features is challenging using current top-down processing techniques. In this contribution, we pioneer the combination of two key avenues in atomic-scale processing: area-selective atomic layer deposition (AS-ALD) and growth of 2D materials, and demonstrate bottom-up processing of 2D WS nanolayers. Area-selective deposition of WS nanolayers is enabled using an ABC-type plasma-enhanced ALD process involving acetylacetone (Hacac) as inhibitor (A), bis(-butylimido)-bis(dimethylamido)-tungsten as precursor (B), and HS plasma as the co-reactant (C) at a low deposition temperature of 250 °C. The developed AS-ALD process results in the immediate growth of WS on SiO while effectively blocking growth on AlO as confirmed by in situ spectroscopic ellipsometry and ex situ X-ray photoelectron spectroscopy measurements. As a proof of concept, the AS-ALD process is demonstrated on patterned AlO/SiO surfaces. The AS-ALD WS films exhibited sharp Raman ( and ) peaks on SiO, a fingerprint of crystalline WS layers, upon annealing at temperatures within the thermal budget of semiconductor back-end-of-line processing (≤450 °C). Our AS-ALD process also allows selective growth on various TMDs and transition metal oxides while blocking growth on HfO and TiO. It is expected that this work will lay the foundation for area-selective ALD of other 2D materials.
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http://dx.doi.org/10.1021/acsmaterialslett.0c00093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7217612PMC
May 2020

Synthesis of a Hybrid Nanostructure of ZnO-Decorated MoS by Atomic Layer Deposition.

ACS Nano 2020 Feb 30;14(2):1757-1769. Epub 2020 Jan 30.

Department of Chemical Engineering , Stanford University , Stanford , California 94305 , United States.

We introduce the synthesis of hybrid nanostructures comprised of ZnO nanocrystals (NCs) decorating nanosheets and nanowires (NWs) of MoS prepared by atomic layer deposition (ALD). The concentration, size, and surface-to-volume ratio of the ZnO NCs can be systematically engineered by controlling both the number of ZnO ALD cycles and the properties of the MoS substrates, which are prepared by sulfurizing ALD MoO. Analysis of the chemical composition combined with electron microscopy and synchrotron X-ray techniques as a function of the number of ZnO ALD cycles, together with the results of quantum chemical calculations, help elucidate the ZnO growth mechanism and its dependence on the properties of the MoS substrate. The defect density and grain size of MoS nanosheets are controlled by the sulfurization temperature of ALD MoO, and the ZnO NCs in turn nucleate selectively at defect sites on MoS surface and enlarge with increasing ALD cycle numbers. At higher ALD cycle numbers, the coalescence of ZnO NCs contributes to an increase in areal coverage and NC size. Additionally, the geometry of the hybrid structures can be tuned by changing the dimensionality of the MoS, by employing vertical NWs of MoS as the substrate for ALD ZnO NCs, which leads to improvement of the relevant surface-to-volume ratio. Such materials are expected to find use in newly expanded applications, especially those such as sensors or photodevices based on a p-n heterojunction which relies on coupling transition-metal dichalcogenides with NCs.
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http://dx.doi.org/10.1021/acsnano.9b07467DOI Listing
February 2020

From the Bottom-Up: Toward Area-Selective Atomic Layer Deposition with High Selectivity.

Chem Mater 2019 Jan 19;31(1):2-12. Epub 2018 Dec 19.

Department of Applied Physics, Eindhoven University of Technology, P. O. Box 513, 5600 MB Eindhoven, The Netherlands.

Bottom-up nanofabrication by area-selective atomic layer deposition (ALD) is currently gaining momentum in semiconductor processing, because of the increasing need for eliminating the edge placement errors of top-down processing. Moreover, area-selective ALD offers new opportunities in many other areas such as the synthesis of catalysts with atomic-level control. This Perspective provides an overview of the current developments in the field of area-selective ALD, discusses the challenge of achieving a high selectivity, and provides a vision for how area-selective ALD processes can be improved. A general cause for the loss of selectivity during deposition is that the character of surfaces on which no deposition should take place changes when it is exposed to the ALD chemistry. A solution is to implement correction steps during ALD involving for example surface functionalization or selective etching. This leads to the development of advanced ALD cycles by combining conventional two-step ALD cycles with correction steps in multistep cycle and/or supercycle recipes.
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http://dx.doi.org/10.1021/acs.chemmater.8b03454DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6369656PMC
January 2019

Atomic Layer Deposition of Cobalt Using H-, N-, and NH-Based Plasmas: On the Role of the Co-reactant.

J Phys Chem C Nanomater Interfaces 2018 Oct 5;122(39):22519-22529. Epub 2018 Sep 5.

Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

This work investigates the role of the co-reactant for the atomic layer deposition of cobalt (Co) films using cobaltocene (CoCp) as the precursor. Three different processes were compared: an AB process using NH plasma, an AB process using H/N plasma, and an ABC process using subsequent N and H plasmas. A connection was made between the plasma composition and film properties, thereby gaining an understanding of the role of the various plasma species. For NH plasma, H and N were identified as the main species apart from the expected NH, whereas for the H/N plasma, NH was detected. Moreover, HCp was observed as a reaction product in the precursor and co-reactant subcycles. Both AB processes showed self-limiting half-reactions and yielded similar material properties, that is, high purity and low resistivity. For the AB process with H/N, the resistivity and impurity content depended on the H/N mixing ratio, which was linked to the production of NH molecules and related radicals. The ABC process resulted in high-resistivity and low-purity films, attributed to the lack of NH species during the co-reactant exposures. The obtained insights are summarized in a reaction scheme where CoCp chemisorbs in the precursor subcycle and NH species eliminate the remaining Cp in the consecutive subcycle.
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http://dx.doi.org/10.1021/acs.jpcc.8b06342DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6174421PMC
October 2018

Area-Selective Atomic Layer Deposition of Metal Oxides on Noble Metals through Catalytic Oxygen Activation.

Chem Mater 2018 Feb 1;30(3):663-670. Epub 2017 Dec 1.

Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, Netherlands.

Area-selective atomic layer deposition (ALD) is envisioned to play a key role in next-generation semiconductor processing and can also provide new opportunities in the field of catalysis. In this work, we developed an approach for the area-selective deposition of metal oxides on noble metals. Using O gas as co-reactant, area-selective ALD has been achieved by relying on the catalytic dissociation of the oxygen molecules on the noble metal surface, while no deposition takes place on inert surfaces that do not dissociate oxygen (i.e., SiO, AlO, Au). The process is demonstrated for selective deposition of iron oxide and nickel oxide on platinum and iridium substrates. Characterization by spectroscopic ellipsometry, transmission electron microscopy, scanning Auger electron spectroscopy, and X-ray photoelectron spectroscopy confirms a very high degree of selectivity, with a constant ALD growth rate on the catalytic metal substrates and no deposition on inert substrates, even after 300 ALD cycles. We demonstrate the area-selective ALD approach on planar and patterned substrates and use it to prepare Pt/FeO core/shell nanoparticles. Finally, the approach is proposed to be extendable beyond the materials presented here, specifically to other metal oxide ALD processes for which the precursor requires a strong oxidizing agent for growth.
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http://dx.doi.org/10.1021/acs.chemmater.7b03818DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828705PMC
February 2018

Area-Selective Atomic Layer Deposition of SiO Using Acetylacetone as a Chemoselective Inhibitor in an ABC-Type Cycle.

ACS Nano 2017 09 7;11(9):9303-9311. Epub 2017 Sep 7.

Department of Applied Physics, Eindhoven University of Technology , P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

Area-selective atomic layer deposition (ALD) is rapidly gaining interest because of its potential application in self-aligned fabrication schemes for next-generation nanoelectronics. Here, we introduce an approach for area-selective ALD that relies on the use of chemoselective inhibitor molecules in a three-step (ABC-type) ALD cycle. A process for area-selective ALD of SiO was developed comprising acetylacetone inhibitor (step A), bis(diethylamino)silane precursor (step B), and O plasma reactant (step C) pulses. Our results show that this process allows for selective deposition of SiO on GeO, SiN, SiO, and WO, in the presence of AlO, TiO, and HfO surfaces. In situ Fourier transform infrared spectroscopy experiments and density functional theory calculations underline that the selectivity of the approach stems from the chemoselective adsorption of the inhibitor. The selectivity between different oxide starting surfaces and the compatibility with plasma-assisted or ozone-based ALD are distinct features of this approach. Furthermore, the approach offers the opportunity of tuning the substrate-selectivity by proper selection of inhibitor molecules.
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http://dx.doi.org/10.1021/acsnano.7b04701DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5665545PMC
September 2017

Area-Selective Atomic Layer Deposition of InO:H Using a μ-Plasma Printer for Local Area Activation.

Chem Mater 2017 Feb 23;29(3):921-925. Epub 2017 Jan 23.

Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands; Department Thin Film Technology, TNO, High Tech Campus 21, 5656 AE Eindhoven, The Netherlands.

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http://dx.doi.org/10.1021/acs.chemmater.6b04469DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5384477PMC
February 2017

Incomplete elimination of precursor ligands during atomic layer deposition of zinc-oxide, tin-oxide, and zinc-tin-oxide.

J Chem Phys 2017 Feb;146(5):052802

Department of Chemical Engineering, Stanford University, Stanford, California 94305, USA.

For atomic layer deposition (ALD) of doped, ternary, and quaternary materials achieved by combining multiple binary ALD processes, it is often difficult to correlate the material properties and growth characteristics with the process parameters due to a limited understanding of the underlying surface chemistry. In this work, in situ Fourier transform infrared (FTIR) spectroscopy was employed during ALD of zinc-oxide, tin-oxide, and zinc-tin-oxide (ZTO) with the precursors diethylzinc (DEZ), tetrakis(dimethylamino)tin (TDMASn), and HO. The main aim was to investigate the molecular basis for the nucleation delay during ALD of ZTO, observed when ZnO ALD is carried out after SnO ALD. Gas-phase FTIR spectroscopy showed that dimethylamine, the main reaction product of the SnO ALD process, is released not only during SnO ALD but also when depositing ZnO after SnO, indicating incomplete removal of the ligands of the TDMASn precursor from the surface. Transmission FTIR spectroscopy performed during ALD on SiO powder revealed that a significant fraction of the ligands persist during both SnO and ZnO ALD. These observations provide experimental evidence for a recently proposed mechanism, based on theoretical calculations, suggesting that the elimination of precursor ligands is often not complete. In addition, it was found that the removal of precursor ligands by HO exposure is even less effective when ZnO ALD is carried out after SnO ALD, which likely causes the nucleation delay in ZnO ALD during the deposition of ZTO. The underlying mechanisms and the consequences of the incomplete elimination of precursor ligands are discussed.
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http://dx.doi.org/10.1063/1.4961459DOI Listing
February 2017

Tandem Core-Shell Si-TaN Photoanodes for Photoelectrochemical Water Splitting.

Nano Lett 2016 12 22;16(12):7565-7572. Epub 2016 Nov 22.

SLAC National Accelerator Laboratory , 2575 Sand Hill Road, Menlo Park. California 94025, United States.

Nanostructured core-shell Si-TaN photoanodes were designed and synthesized to overcome charge transport limitations of TaN for photoelectrochemical water splitting. The core-shell devices were fabricated by atomic layer deposition of amorphous TaO onto nanostructured Si and subsequent nitridation to crystalline TaN. Nanostructuring with a thin shell of TaN results in a 10-fold improvement in photocurrent compared to a planar device of the same thickness. In examining thickness dependence of the TaN shell from 10 to 70 nm, superior photocurrent and absorbed-photon-to-current efficiencies are obtained from the thinner TaN shells, indicating minority carrier diffusion lengths on the order of tens of nanometers. The fabrication of a heterostructure based on a semiconducting, n-type Si core produced a tandem photoanode with a photocurrent onset shifted to lower potentials by 200 mV. CoTiO and NiO water oxidation cocatalysts were deposited onto the Si-TaN to yield active photoanodes that with NiO retained 50-60% of their maximum photocurrent after 24 h chronoamperometry experiments and are thus among the most stable TaN photoanodes reported to date.
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http://dx.doi.org/10.1021/acs.nanolett.6b03408DOI Listing
December 2016

A Process for Topographically Selective Deposition on 3D Nanostructures by Ion Implantation.

ACS Nano 2016 04 15;10(4):4451-8. Epub 2016 Mar 15.

Applied Materials , 974 East Arques Avenue, M/S 81280, Sunnyvale, California 94085, United States.

Area-selective atomic layer deposition (AS-ALD) is attracting increasing interest because of its ability to enable both continued dimensional scaling and accurate pattern placement for next-generation nanoelectronics. Here we report a strategy for depositing material onto three-dimensional (3D) nanostructures with topographic selectivity using an ALD process with the aid of an ultrathin hydrophobic surface layer. Using ion implantation of fluorocarbons (CFx), a hydrophobic interfacial layer is formed, which in turn causes significant retardation of nucleation during ALD. We demonstrate the process for Pt ALD on both blanket and 2D patterned substrates. We extend the process to 3D structures, demonstrating that this method can achieve selective anisotropic deposition, selectively inhibiting Pt deposition on deactivated horizontal regions while ensuring that only vertical surfaces are decorated during ALD. The efficacy of the approach for metal oxide ALD also shows promise, though further optimization of the implantation conditions is required. The present work advances practical applications that require area-selective coating of surfaces in a variety of 3D nanostructures according to their topographical orientation.
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http://dx.doi.org/10.1021/acsnano.6b00094DOI Listing
April 2016

Atomic layer deposition of Pd and Pt nanoparticles for catalysis: on the mechanisms of nanoparticle formation.

Nanotechnology 2016 Jan 4;27(3):034001. Epub 2015 Dec 4.

Department of Applied Physics, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.

The deposition of Pd and Pt nanoparticles by atomic layer deposition (ALD) has been studied extensively in recent years for the synthesis of nanoparticles for catalysis. For these applications, it is essential to synthesize nanoparticles with well-defined sizes and a high density on large-surface-area supports. Although the potential of ALD for synthesizing active nanocatalysts for various chemical reactions has been demonstrated, insight into how to control the nanoparticle properties (i.e. size, composition) by choosing suitable processing conditions is lacking. Furthermore, there is little understanding of the reaction mechanisms during the nucleation stage of metal ALD. In this work, nanoparticles synthesized with four different ALD processes (two for Pd and two for Pt) were extensively studied by transmission electron spectroscopy. Using these datasets as a starting point, the growth characteristics and reaction mechanisms of Pd and Pt ALD relevant for the synthesis of nanoparticles are discussed. The results reveal that ALD allows for the preparation of particles with control of the particle size, although it is also shown that the particle size distribution is strongly dependent on the processing conditions. Moreover, this paper discusses the opportunities and limitations of the use of ALD in the synthesis of nanocatalysts.
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http://dx.doi.org/10.1088/0957-4484/27/3/034001DOI Listing
January 2016