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Pedersen, Henrik, ProfessorORCID iD iconorcid.org/0000-0002-7171-5383
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Publications (10 of 92) Show all publications
Choolakkal, A. H., Niiranen, P., Dorri, S., Birch, J. & Pedersen, H. (2024). Competitive co-diffusion as a route to enhanced step coverage in chemical vapor deposition. Nature Communications, 15(1)
Open this publication in new window or tab >>Competitive co-diffusion as a route to enhanced step coverage in chemical vapor deposition
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2024 (English)In: Nature Communications, E-ISSN 2041-1723, Vol. 15, no 1Article in journal (Refereed) Published
Abstract [en]

Semiconductor devices are constructed from stacks of materials with different electrical properties, making deposition of thin layers central in producing semiconductor chips. The shrinking of electronics has resulted in complex device architectures which require deposition into holes and recessed features. A key parameter for such deposition is the step coverage (SC), which is the ratio of the thickness of material at the bottom and at the top. Here, we show that adding a co-flow of a heavy inert gas affords a higher SC for deposition by chemical vapor deposition (CVD). By adding a co-flow of Xe to a CVD process for boron carbide using a single source precursor with a lower molecular mass than the atomic mass of Xe, the SC increased from 0.71 to 0.97 in a 10:1 aspect ratio feature. The concept was further validated by a longer deposition depth in lateral high aspect ratio structures. We suggest that competitive co-diffusion is a general route to conformal CVD.

Place, publisher, year, edition, pages
Springer Nature, 2024
National Category
Chemical Sciences
Identifiers
urn:nbn:se:liu:diva-210410 (URN)10.1038/s41467-024-55007-1 (DOI)001376553500008 ()2-s2.0-85211616208 (Scopus ID)
Note

Funding: Open access funding provided by Linköping University.

Swedish research council [2018-05499]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]; Swedish research council VR-RFI [2019-00191]; Linkoping University

Available from: 2024-12-12 Created: 2024-12-12 Last updated: 2025-01-15Bibliographically approved
Rowe, C., Kashyap, A., Sharma, G., Goyal, N., Alauzun, J. G., Barry, S. T., . . . Ramanath, G. (2024). Nanomolecularly-induced Effects at Titania/Organo-Diphosphonate Interfaces for Stable Hybrid Multilayers with Emergent Properties. ACS Applied Nano Materials, 7(10), 11225-11233
Open this publication in new window or tab >>Nanomolecularly-induced Effects at Titania/Organo-Diphosphonate Interfaces for Stable Hybrid Multilayers with Emergent Properties
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2024 (English)In: ACS Applied Nano Materials, E-ISSN 2574-0970, Vol. 7, no 10, p. 11225-11233Article in journal (Refereed) Published
Abstract [en]

Nanoscale hybrid inorganic-organic multilayers are attractive for accessing emergent phenomena and properties through superposition of nanomolecularly-induced interface effects for diverse applications. Here, we demonstrate the effects of interfacial molecular nanolayers (MNLs) of organo-diphosphonates on the growth and stability of titania nanolayers during the synthesis of titania/MNL multilayers by sequential atomic layer deposition and single-cycle molecular layer deposition. Interfacial organo-diphosphonate MNLs result in similar to 20-40% slower growth of amorphous titania nanolayers and inhibit anatase nanocrystal formation from them when compared to amorphous titania grown without MNLs. Both these effects are more pronounced in multilayers with aliphatic backbone-MNLs and likely related to impurity incorporation and incomplete reduction of the titania precursor indicated by our spectroscopic analyses. In contrast, both MNLs result in two-fold higher titania nanolayer roughness, suggesting that roughening is primarily due to MNL bonding chemistry. Such MNL-induced effects on inorganic nanolayer growth rate, roughening, and stability are germane to realizing high-interface-fraction hybrid nanolaminate multilayers.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2024
Keywords
inorganic-organic hybrid materials; thin filmgrowth; multilayers; atomic layer deposition; molecular layer deposition; molecular nanolayer; morphology
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-203757 (URN)10.1021/acsanm.4c00743 (DOI)001225391300001 ()38808308 (PubMedID)2-s2.0-85192330081 (Scopus ID)
Note

Funding Agencies|Division of Civil, Mechanical and Manufacturing Innovation [CMMI 2135725]; US National Science Foundation [2009 00971]; Swedish Government Strategic Research Area in Materials Science on Functional Materials grant SFO-Mat-LiU [KAW-2020.0196]; Knut and Alice Wallenberg foundation through the Wallenberg Academy Fellows grant [2021-03826]; Swedish Research Council through the VR [DST/INT/SWD/VR/P-18/2019]; DST India [RGPIN-2019-06213]; NSERC

Available from: 2024-05-28 Created: 2024-05-28 Last updated: 2025-04-07Bibliographically approved
Mpofu, P., Hafdi, H., Niiranen, P., Lauridsen, J., Alm, O., Larsson, T. & Pedersen, H. (2024). Surface chemistry in atomic layer deposition of AlN thin films from Al(CH3)3 and NH3 studied by mass spectrometry. Journal of Materials Chemistry C, 12(33), 12818-12824
Open this publication in new window or tab >>Surface chemistry in atomic layer deposition of AlN thin films from Al(CH3)3 and NH3 studied by mass spectrometry
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2024 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 12, no 33, p. 12818-12824Article in journal (Refereed) Published
Abstract [en]

Aluminum nitride (AlN) is a semiconductor with a very wide band gap and a potential dielectric material. Deposition of thin AlN films is routinely done by several techniques, including atomic layer deposition (ALD). In this study, we deposited AlN using ALD with trimethylaluminum (TMA) as the Al precursor and ammonia (NH3) with and without plasma activation as the N precursor in the temperature range from 100 to 400 degrees C while monitoring the surface reactions using mass spectrometry. Our results, combined with recent quantum chemical modelling, suggest that the surface chemistry of the deposition process is chemisorption of TMA followed by reductive elimination of the methyl groups to render mono methyl aluminum species. The NH3 chemisorption is done by ligand exchange to form CH4 and an -NH2 terminated surface.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2024
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-206341 (URN)10.1039/d4tc01867b (DOI)001276154900001 ()
Note

Funding Agencies|Swedish foundation for Strategic Research through the project ''Time-resolved low temperature CVD for III-nitrides'' [SSF-RMA 15-0018]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University [2009-00971]

Available from: 2024-08-16 Created: 2024-08-16 Last updated: 2025-04-14Bibliographically approved
Rönnby, K., Pedersen, H. & Ojamäe, L. (2023). On the limitations of thermal atomic layer deposition of InN using ammonia. Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, 41(2), Article ID 020401.
Open this publication in new window or tab >>On the limitations of thermal atomic layer deposition of InN using ammonia
2023 (English)In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, no 2, article id 020401Article in journal (Refereed) Published
Abstract [en]

Chemical vapor deposition of indium nitride (InN) is severely limited by the low thermal stability of the material, and, thus, low-temperature deposition processes such as atomic layer deposition (ALD) are needed to deposit InN films. The two chemically and structurally closely related materials—aluminum nitride and gallium nitride (GaN)—can be deposited by both plasma and thermal ALD, with ammonia (NH3) as a nitrogen precursor in thermal processes. InN, however, can only be deposited using plasma ALD, indicating that there might be a limitation to thermal ALD with NH3 for InN. We use quantum-chemical density functional theory calculations to compare the adsorption process of NH3 on GaN and InN to investigate if differences in the process could account for the lack of thermal ALD of InN. Our findings show a similar reactive adsorption mechanism on both materials, in which NH3 could adsorb onto a vacant site left by a desorbing methyl group from the surfaces. The difference in energy barrier for this adsorption indicates that the process is many magnitudes slower on InN compared to GaN. Slow kinetics would hinder NH3 from reactively adsorbing onto InN in the timeframe of the ALD growth process and, thus, limit the availability of a thermal ALD process.

Place, publisher, year, edition, pages
American Vacuum Society, 2023
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-191934 (URN)10.1116/6.0002355 (DOI)000936907900001 ()
Note

Funding agencies: This project was funded by the Swedish Foundation for Strategic Research through the project “Time-resolved low temperature CVD for III-nitrides” (No. SSF-RMA 15-0018). L.O. acknowledges financial support from the Swedish Research Council (VR). Supercomputing resources were provided by the Swedish National Infrastructure for Computing (SNIC) and the Swedish National Supercomputer Centre (NSC).

Available from: 2023-02-24 Created: 2023-02-24 Last updated: 2023-03-21Bibliographically approved
Huang, J.-J., Militzer, C., Xu, J., Wijayawardhana, C., Forsberg, U. & Pedersen, H. (2022). Growth of silicon carbide multilayers with varying preferred growth orientation. Surface & Coatings Technology, 447, Article ID 128853.
Open this publication in new window or tab >>Growth of silicon carbide multilayers with varying preferred growth orientation
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2022 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 447, article id 128853Article in journal (Refereed) Published
Abstract [en]

SiC multilayer coatings were deposited via thermal chemical vapor deposition (CVD) using silicon tetrachloride (SiCl4) and various hydrocarbons under identical growth conditions, i.e. at 1100 °C and 10 kPa. The coatings consisted of layers whose preferred growth orientation alternated between random and highly 〈111〉-oriented. The randomly oriented layers were prepared with either methane (CH4) or ethylene (C2H4) as carbon precursor, whereas the highly 〈111〉-oriented layers were grown utilizing toluene (C7H8) as carbon precursor. In this work, we demonstrated how to fabricate multilayer coatings with different growth orientations by merely switching between hydrocarbons. Moreover, the success in depositing multilayer coatings on both flat and structured graphite substrates has strengthened the assumption proposed in our previous study that the growth of highly 〈111〉-oriented SiC coatings using C7H8 was primarily driven by chemical surface reactions.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Silicon carbide, Preferred growth orientation, Chemical vapor deposition, Multilayer, Toluene
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-189572 (URN)10.1016/j.surfcoat.2022.128853 (DOI)000863260100006 ()
Note

Funding: SGL Carbon GmbH

Available from: 2022-10-27 Created: 2022-10-27 Last updated: 2022-11-08Bibliographically approved
Souqui, L., Sharma, S., Högberg, H. & Pedersen, H. (2022). Texture evolution in rhombohedral boron carbide films grown on 4H-SiC(0001) and 4H-SiC(0001) substrates by chemical vapor deposition. Dalton Transactions, 51(41), 15974-15982
Open this publication in new window or tab >>Texture evolution in rhombohedral boron carbide films grown on 4H-SiC(0001) and 4H-SiC(0001) substrates by chemical vapor deposition
2022 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 51, no 41, p. 15974-15982Article in journal (Refereed) Published
Abstract [en]

Boron carbide in its rhombohedral form (r-BxC), commonly denoted B4C or B13C2, is a well-known hard material, but it is also a potential semiconductor material. We deposited r-BxC by chemical vapor deposition between 1100 degrees C and 1500 degrees C from triethylboron in H-2 on 4H-SiC(0001) and 4H-SiC(0001). We show, using ToF-ERDA, that pure B4C was grown at 1300 degrees C, furthermore, using XRD that graphite forms above 1400 degrees C. The films deposited above 1300 degrees C on 4H-SiC(0001) were found to be epitaxial, with the epitaxial relationships B4C(0001)[1010]||4H-SiC(0001)[1010] obtained from pole figure measurements. In contrast, the films deposited on 4H-SiC(0001) were polycrystalline. We suggest that the difference in growth mode is explained by the difference in the ability of the different surfaces of 4H-SiC to act as carbon sources in the initial stages of the film growth.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2022
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-189323 (URN)10.1039/d2dt02107b (DOI)000863910500001 ()36197373 (PubMedID)
Note

Funding Agencies|Swedish Foundation for Strategic Research (SSF) [IS14-0027]; Carl Tryggers Foundation for Scientific Research [CTS 14:189]; Swedish Research Council (VR) [2018-05499, 2017-04164]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Swedish Research Council VR-RFI [2019-00191]

Available from: 2022-10-19 Created: 2022-10-19 Last updated: 2024-05-02Bibliographically approved
Mpofu, P., Rouf, P., O´brien, N., Forsberg, U. & Pedersen, H. (2022). Thermal atomic layer deposition of In2O3 thin films using a homoleptic indium triazenide precursor and water. Dalton Transactions, 51(12), 4712-4719
Open this publication in new window or tab >>Thermal atomic layer deposition of In2O3 thin films using a homoleptic indium triazenide precursor and water
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2022 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 51, no 12, p. 4712-4719Article in journal (Refereed) Published
Abstract [en]

Indium oxide (In2O3) is an important transparent conducting material widely used in optoelectronic applications. Herein, we study the deposition of In2O3 by thermal atomic layer deposition (ALD) using our recently reported indium(iii) triazenide precursor and H2O. A temperature interval with self-limiting growth was found between similar to 270 and 385 degrees C with a growth per cycle of similar to 1.0 angstrom. The deposited films were polycrystalline cubic In2O3 with In : O ratios of 1 : 1.2, and low levels of C and no detectable N impurities. The transmittance of the films was found to be >70% in visible light and the resistivity was found to be 0.2 m omega cm. The high growth rates, low impurities, high optical transmittance, and low resistivity of these films give promise to this process being used for ALD of In2O3 films for future microelectronic displays.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2022
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-183776 (URN)10.1039/d1dt03748j (DOI)000763001500001 ()35234773 (PubMedID)
Note

Funding Agencies|Swedish Foundation for Strategic ResearchSwedish Foundation for Strategic Research [SSF-RMA 15-0018]; Swedish Institute

Available from: 2022-03-25 Created: 2022-03-25 Last updated: 2023-04-13Bibliographically approved
Damas, G., Rönnby, K., Pedersen, H. & Ojamäe, L. (2022). Understanding indium nitride thin film growth under ALD conditions by atomic scale modelling: From the bulk to the In-rich layer. Applied Surface Science, 592, Article ID 153290.
Open this publication in new window or tab >>Understanding indium nitride thin film growth under ALD conditions by atomic scale modelling: From the bulk to the In-rich layer
2022 (English)In: Applied Surface Science, ISSN 0169-4332, Vol. 592, article id 153290Article in journal (Refereed) Published
Abstract [en]

In recent decades, indium nitride (InN) has been attracting a great deal of attention for its potential applicability in the field of light-emitting diodes (LEDs) and high-frequency electronics. However, the contribution from adsorption- and reaction- related processes at the atomic scale level to the InN growth has not yet been unveiled, limiting the process optimization that is essential to achieve highly crystalline and pure thin films. In this report, we investigate the reaction pathways that are involved in the crystal growth of InN thin film in atomic layer deposition (ALD) techniques from trimethylindium (TMI) and ammonia (NH3) precursors. To accomplish this task, we use a solid-state approach to perform the ab-initio calculations within the Perdew–Burke–Ernzerhof functional (PBE) level of theory. The results clarify the activation role from the N-rich layer to decrease the barrier for the first TMI precursor dissociation from Δ‡H= +227 kJ/mol, in gas phase, to solely +16 kJ/mol, in the surface environment. In either case, the subsequent CH3 release is found to be thermo- and kinetically favored with methylindium (MI) formed at the hcp site and ethane (C2H6) as the byproduct. In the following step, the TMI physisorption at a nearby occupied hcp site promotes the sequential hydrogen removal from the N-rich layer at the minimum energy cost of Δ‡H < +105 kJ/mol with methane (CH4) release. An alternative mechanism involving the production of CH4 is also feasible upon dissociation in gas phase. Furthermore, the high concentration of CH3 radicals, from precursor dissociation, might be the origin of the carbon impurities in this material under the experimental conditions of interest. Finally, the passivation methodology is not found to affect the evaluation of the surface-related processes, whereas the inclusion of spin-polarization is demonstrated to be essential to the proper understanding of the reaction mechanism.

Place, publisher, year, edition, pages
Amsterdam, Netherlands: Elsevier, 2022
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-184437 (URN)10.1016/j.apsusc.2022.153290 (DOI)000793249200004 ()2-s2.0-85127669955 (Scopus ID)
Note

Funding: (SSF) through the project Time-Resolved Low temperature CVD [SSF-RMA 15-0018]; Swedish Research Council (VR)

Available from: 2022-04-20 Created: 2022-04-20 Last updated: 2022-05-23Bibliographically approved
Nadhom, H., Boyd, R., Rouf, P., Lundin, D. & Pedersen, H. (2021). Area Selective Deposition of Metals from the Electrical Resistivity of the Substrate. The Journal of Physical Chemistry Letters, 12(17), 4130-4133
Open this publication in new window or tab >>Area Selective Deposition of Metals from the Electrical Resistivity of the Substrate
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2021 (English)In: The Journal of Physical Chemistry Letters, E-ISSN 1948-7185, The Journal of Physical Chemistry Letters, Vol. 12, no 17, p. 4130-4133Article in journal (Refereed) Published
Abstract [en]

Area selective deposition (ASD) of films only on desired areas of the substrate opens for less complex fabrication of nanoscaled electronics. We show that a newly developed CVD method, where plasma electrons are used as the reducing agent in deposition of metallic thin films, is inherently area selective from the electrical resistivity of the substrate surface. When depositing iron with the new CVD method, no film is deposited on high-resistivity SiO2 surfaces whereas several hundred nanometers thick iron films are deposited on areas with low resistivity, obtained by adding a thin layer of silver on the SiO2 surface. On the basis of such a scheme, we show how to use the electric resistivity of the substrate surface as an extension of the ASD toolbox for metal-on-metal deposition.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2021
Keywords
Iron, Thin films, Deposition, Plasma, Chemical vapor deposition
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:liu:diva-175778 (URN)10.1021/acs.jpclett.1c00415 (DOI)000648878200004 ()
Funder
Swedish Research Council, 2015-03803; 2019-05055Swedish Foundation for Strategic Research , SSF-RMA 15-0018
Note

Funding: Swedish Research Council (VR)Swedish Research Council [2015-03803, 2019-05055]; Swedish Foundation for Strategic Research (SSF)Swedish Foundation for Strategic Research [SSF-RMA 15-0018]; Lam Research Corporation

Available from: 2021-05-21 Created: 2021-05-21 Last updated: 2024-07-04Bibliographically approved
Rouf, P., O´brien, N., Buttera, S. C., Martinovic, I., Bakhit, B., Martinsson, E., . . . Pedersen, H. (2020). Epitaxial GaN using Ga(NMe2)3 and NH3 plasma by Atomic Layer Deposition. Journal of Materials Chemistry C, 8(25), 8457-8465
Open this publication in new window or tab >>Epitaxial GaN using Ga(NMe2)3 and NH3 plasma by Atomic Layer Deposition
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2020 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 8, no 25, p. 8457-8465Article in journal (Refereed) Published
Abstract [en]

Low temperature deposition of high-quality epitaxial GaN is crucial for its integration in electronic applications. Chemical vapor deposition at approximately 800 °C using SiC with an AlN buffer layer or nitridized sapphire as substrate is used to facilitate the GaN growth. Here, we present a low temperature atomic layer deposition (ALD) process using tris(dimethylamido)gallium(III) with NH3 plasma. The ALD process shows self-limiting behaviour between 130–250 °C with a growth rate of 1.4 Å per cycle. The GaN films produced were crystalline on Si (100) at all deposition temperatures with a near stochiometric Ga/N ratio with low carbon and oxygen impurities. When GaN was deposited on 4H-SiC, the films grew epitaxially without the need for an AlN buffer layer, which has never been reported before. The bandgap of the GaN films was measured to be ∼3.42 eV and the Fermi level showed that the GaN was unintentionally n-type doped. This study shows the potential of ALD for GaN-based electronic devices.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2020
National Category
Materials Chemistry
Identifiers
urn:nbn:se:liu:diva-169938 (URN)10.1039/d0tc02085k (DOI)000545331300009 ()2-s2.0-85087704720 (Scopus ID)
Available from: 2020-09-25 Created: 2020-09-25 Last updated: 2022-09-05Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-7171-5383

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