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  • 101.
    Rönnby, Karl
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Ojamäe, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Kinetic modeling of ammonia decomposition at chemical vapor deposition conditions2020Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 38, nr 5, artikel-id 050402Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Kinetic modeling has been used to study the decomposition chemistry of ammonia at a wide range of temperatures, pressures, concentrations, and carrier gases mimicking the conditions in chemical vapor deposition (CVD) of metal nitrides. The modeling shows that only a small fraction of the ammonia molecules will decompose at most conditions studied. This suggests that the fact that the high NH3 to metal ratios often employed in CVD is due to the very low amount of reactive decomposition products being formed rather than due to rapid decomposition of ammonia into stable dinitrogen and dihydrogen as suggested by purely thermodynamic equilibrium models.

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  • 102.
    Rönnby, Karl
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Ojamäe, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    On the limitations of thermal atomic layer deposition of InN using ammonia2023Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, nr 2, artikel-id 020401Artikel i tidskrift (Refereegranskat)
    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.

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  • 103.
    Sadowski, Grzegorz
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Malmo Univ, Sweden.
    Shu, Rui
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Laboratoriet för organisk elektronik. Linköpings universitet, Tekniska fakulteten.
    Le Febvrier, Arnaud
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Han, Zhijia
    Southern Univ Sci & Technol, Peoples R China.
    Music, Denis
    Malmo Univ, Sweden; Malmo Univ, Sweden.
    Liu, Weishu
    Southern Univ Sci & Technol, Peoples R China; Southern Univ Sci & Technol, Peoples R China.
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Structural evolution and thermoelectric properties of Mg3SbxBi2-x thin films deposited by magnetron sputtering2023Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, nr 4, artikel-id 043409Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mg3Bi2-based compounds are of great interest for thermoelectric applications near room temperature. Here, undoped p-type Mg3SbxBi2-x thin films were synthesized using magnetron sputtering (three elemental targets in Ar atmosphere) with a growth temperature of 200 ? on three different substrates, namely, Si as well as c- and r-sapphire. The elemental composition was measured with energy-dispersive x-ray spectroscopy and the structure by x-ray diffraction. The electrical resistivity and the Seebeck coefficient were determined under He atmosphere from room temperature to the growth temperature. All samples are crystalline exhibiting the La2O3-type crystal structure (space group P-3m1). The observed thermoelectric response is consistent with a semiconductive behavior. With increasing x, the samples become more electrically resistive due to the increasing bandgap. High Bi content (x < 1) is thus beneficial due to lower resistivity and a higher power factor near room temperature. Thermoelectric thin films synthesized at low temperatures may provide novel pathways to enable flexible devices on polymeric and other heat-sensitive substrates.

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  • 104.
    Salamania, Janella
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Seco Tools AB, Sweden.
    Farhadizadeh, Alireza
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Kwick, K. M. Calamba
    Sandvik Coromant AB, Sweden.
    Schramm, I. C.
    Sandvik Coromant AB, Sweden.
    Hsu, Tun-Wei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Sandvik Coromant AB, Sweden.
    Johnson, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten. Sandvik Coromant AB, Sweden.
    Rogström, Lina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska fakulteten.
    Influence of nitrogen vacancies on the decomposition route and age hardening of wurtzite Ti1−xAlxNy thin films2023Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, nr 6, artikel-id 063413Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The wurtzite phase of TiAlN has been known to form in industrial grade coatings with high Al content; yet, a significant knowledge gap exists regarding its behavior at high temperatures and the impact of defects on its properties. Specifically, its response to high temperatures and the implications of defects on its characteristics are poorly understood. Here, the high-temperature decomposition of nitrogen-deficient epitaxial wurtzite Ti1-xAlxNy (x = 0.79-0.98, y = 0.82-0.86) films prepared by reactive magnetron sputtering was investigated using x-ray diffractometry and high-resolution scanning transmission electron microscopy. The results show that wurtzite Ti(1-x)Al(x)Ny decomposes by forming intermediary MAX phases, which then segregate into pure c-TiN and w-AlN phases after high-temperature annealing and intermetallic TiAl nanoprecipitates. The semicoherent interfaces between the wurtzite phase and the precipitates cause age hardening of approximately 4-6 GPa, which remains even after annealing at 1200 degrees C. These findings provide insight into how nitrogen vacancies can influence the decomposition and mechanical properties of wurtzite TiAlN.

  • 105.
    Samuelsson, Mattias
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik.
    Lundin, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Sarakinos, Kostas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Bjorefors, Fredrik
    Uppsala University, Sweden.
    Walivaara, Bengt
    Impact Coatings, Linköping, Sweden.
    Ljungcrantz, Henrik
    Impact Coatings, Linköping, Sweden.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Influence of ionization degree on film properties when using high power impulse magnetron sputtering2012Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 30, nr 3, s. 031507-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chromium thin films are deposited by combining direct current magnetron sputtering and high power impulse magnetron sputtering (HiPIMS) on a single cathode in an industrial deposition system. While maintaining a constant deposition rate and unchanged metal ion energy distribution function, the fraction of the total power supplied by either deposition technique is altered, and thereby also the metal ion to metal neutral ratio of the deposition flux. It is observed that the required total average power needed to be proportionally increased as the HiPIMS fraction is increased to be able to keep a constant deposition rate. The influence on microstructure, electrical, and electrochemical properties of the films is investigated and shows improvements with the use of HiPIMS. However, considerable influence of the studied properties occurs already when only some 40% of the total power is supplied by the HiPIMS technique. Further increase of the HiPIMS power fraction results in comparatively minor influence of the studied properties yet significant deposition rate efficiency reduction. The results show that the degree of ionization can be controlled separately, and that the advantages associated with using HiPIMS can be obtained while much of the deposition rate reduction, often reported for HiPIMS, can be avoided.

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  • 106.
    Schmidt, Susann
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Czigany, Zsolt
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Jensen, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Influence of inert gases on the reactive high power pulsed magnetron sputtering process of carbon-nitride thin films2013Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 31, nr 1, s. 011503-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of inert gases (Ne, Ar, Kr) on the sputter process of carbon and carbon-nitride (CNx) thin films was studied using reactive high power pulsed magnetron sputtering (HiPIMS). Thin solid films were synthesized in an industrial deposition chamber from a graphite target. The peak target current during HiPIMS processing was found to decrease with increasing inert gas mass. Time averaged and time resolved ion mass spectroscopy showed that the addition of nitrogen, as reactive gas, resulted in less energetic ion species for processes employing Ne, whereas the opposite was noticed when Ar or Kr were employed as inert gas. Processes in nonreactive ambient showed generally lower total ion fluxes for the three different inert gases. As soon as N-2 was introduced into the process, the deposition rates for Ne and Ar-containing processes increased significantly. The reactive Kr-process, in contrast, showed slightly lower deposition rates than the nonreactive. The resulting thin films were characterized regarding their bonding and microstructure by x-ray photoelectron spectroscopy and transmission electron microscopy. Reactively deposited CNx thin films in Ar and Kr ambient exhibited an ordering toward a fullerene-like structure, whereas carbon and CNx films deposited in Ne atmosphere were found to be amorphous. This is attributed to an elevated amount of highly energetic particles observed during ion mass spectrometry and indicated by high peak target currents in Ne-containing processes. These results are discussed with respect to the current understanding of the structural evolution of a-C and CNx thin films.

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  • 107.
    Sharma, Sachin
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Souqui, Laurent
    Univ Illinois, IL 61801 USA.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Chemical vapor deposition of sp(2)-boron nitride films on Al2O3 (0001), (11 2 over bar 0), (1 1 over bar 02), and (10 1 over bar 0) substrates2022Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 40, nr 3, artikel-id 033404Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin films of boron nitride in its sp(2)-hybridized form (sp(2)-BN) have potential uses in UV devices and dielectrics. Here, we explore chemical vapor deposition (CVD) of sp(2)-BN on various cuts of sapphire: Al2O3 ( 11 2 over bar 0 ), Al2O3 ( 1 1 over bar 02 ), Al2O3 ( 10 1 over bar 0 ), and Al2O3 (0001) using two CVD processes with two different boron precursors triethylborane and trimethylborane. Fourier transform infrared spectroscopy shows that sp(2)-BN grows on all the sapphire substrates; using x-ray diffraction, 2 theta/omega diffractogram shows that only Al2O3 ( 11 2 over bar 0 ) and Al2O3 (0001) rendered crystalline films: and using phi(phi)-scans, growth of the rhombohedral polytype (r-BN) films on these substrates is confirmed. These films were found to be epitaxially grown on an AlN interlayer with comparatively higher crystalline quality for the films grown on the Al2O3 ( 11 2 over bar 0 ) substrate, which is determined using omega(omega)-scans. Our study suggests that Al2O3 ( 11 2 over bar 0 ) is the most favorable sapphire substrate to realize the envisioned applications of r-BN films.

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  • 108.
    Souqui, Laurent
    et al.
    Univ Illinois, IL 61801 USA.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Chemical vapor deposition of amorphous boron carbide coatings from mixtures of trimethylboron and triethylboron2023Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, nr 6, artikel-id 063412Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Amorphous BxC films were deposited from the coreaction of triethylboron (TEB) and trimethylboron (TMB) at 700 C-degrees in H-2. We observed that combining both precursors allows us to balance their deposition kinetics and yields higher growth rates. Quantitative analysis by x-ray photoelectron spectroscopy shows that a wide range of B/C ratios between 0.7 and 4.1 could be obtained by varying the TEB:TMB ratio. Raman spectroscopy was used to assess the bonding in the films that gradually evolved from a structure similar to that of a-B, to a mixture of half-icosahedra embedded in a carbon matrix to a graphitic structure, as the carbon content increased. The addition of TMB in the gas phase was found to result in a decrease in elasticity and hardness but an improved adhesion, resulting in complex crack patterns upon cleaving, such as sinusoidal cracks and loops. On the one hand, the incorporation of carbon from TMB leads to an increasing contribution of the softer carbon matrix, to the detriment of polyhedral B-C structures, which in turn decreases Youngs modulus and hardness. On the other hand, it suggests that near the film-substrate interface, the presence of the carbon matrix affords a high density of strong carbon-based bonds, resulting in improved adhesion and preventing delamination of the coatings.

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  • 109.
    Souqui, Laurent
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Palisaitis, Justinas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Rhombohedral boron nitride epitaxy on ZrB22021Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 39, nr 1, artikel-id 013405Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Epitaxial rhombohedral boron nitride (r-BN) films were deposited on ZrB2(0001)/4H-SiC(0001) by chemical vapor deposition at 1485 degrees C from the reaction of triethylboron and ammonia and with a minute amount of silane (SiH4). X-ray diffraction (XRD) w-scans yield the epitaxial relationships of r-BN(0001) k ZrB2(0001) out-of-plane and r-BN[11-20] k ZrB2[11-20] in-plane. Cross-sectional transmission electron microscopy (TEM) micrographs showed that epitaxial growth of r-BN films prevails to similar to 10 nm. Both XRD and TEM demonstrate the formation of carbon- and nitrogen-containing cubic inclusions at the ZrB2 surface. Quantitative analysis from x-ray photoelectron spectroscopy of the r-BN films shows B/N ratios between 1.30 and 1.20 and an O content of 3-4 at. %. Plan-view scanning electron microscopy images reveal a surface morphology where an amorphous material comprising B, C, and N is surrounding the epitaxial twinned r-BN crystals.

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  • 110.
    Souqui, Laurent
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Chemical vapor deposition of sp(2)-boron nitride on Si(111) substrates from triethylboron and ammonia: Effect of surface treatments2020Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 38, nr 4, artikel-id 043402Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thin films of the sp(2)-hybridized polytypes of boron nitride (BN) are interesting materials for several electronic applications such as UV devices. Deposition of epitaxial sp(2)-BN films has been demonstrated on several technologically important semiconductor substrates such as SiC and Al2O3 and where controlled thin film growth on Si would be beneficial for integration of sp(2)-BN in many electronic device systems. The authors investigate the growth of BN films on Si(111) by chemical vapor deposition from triethylboron [B(C2H5)(3)] and ammonia (NH3) at 1300 degrees C with focus on treatments of the Si(111) surface by nitridation, carbidization, or nitridation followed by carbidization prior to BN growth. Fourier transform infrared spectroscopy shows that the BN films deposited exhibit sp(2) bonding. X-ray diffraction reveals that the sp(2)-BN films predominantly grow amorphous on untreated and pretreated Si(111), but with diffraction data showing that turbostratic BN can be deposited on Si(111) when the formation of Si3N4 is avoided. The authors accomplish this condition by combining the nitridation procedure with reactions from the walls on which BxC had previously been deposited.

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  • 111.
    Souqui, Laurent
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Thermal chemical vapor deposition of epitaxial rhombohedral boron nitride from trimethylboron and ammonia2019Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 37, nr 2, artikel-id 020603Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Epitaxial rhombohedral boron nitride (r-BN) films were deposited on alpha-Al2O3(001) substrates by chemical vapor deposition, using trimethylboron, ammonia, and a low concentration of silane in the growth flux. The depositions were performed at temperatures from 1200 to 1485 degrees C, pressures from 30 to 90 mbar, and N/B ratios from 321 to 1286. The most favorable conditions for epitaxy were a temperature of 1400 degrees C, N/B around 964, and pressures below 40 mbar. Analysis by thin film x-ray diffraction showed that most deposited films were polytype-pure epitaxial r-BN with an out-of-plane epitaxial relationship of r-BN[001] parallel to w-AlN[001] parallel to alpha-Al2O3[001] and with two in-plane relationships of r-BN[110] parallel to w-AlN[110] parallel to alpha-Al2O3[100] and r-BN[110] parallel to w-AlN[110] parallel to alpha-Al2O3[(1) over bar 00] due to twinning. Published by the AVS.

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  • 112.
    Sroba, Viktor
    et al.
    Comenius Univ, Slovakia.
    Viskupova, Katarina
    Comenius Univ, Slovakia.
    Wicher, Bartosz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Warsaw Univ Technol, Poland.
    Rogoz, Vladyslav
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Li, Xiao
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Mikula, Marian
    Comenius Univ, Slovakia; Slovak Acad Sci, Slovakia.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Cross-ionization of the sputtered flux during hybrid high power impulse/direct-current magnetron co-sputtering2024Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 42, nr 2, artikel-id 023410Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Time-resolved ion mass spectrometry is used to analyze the type and the energy of metal-ion fluxes during hybrid high-power impulse/direct-current magnetron co-sputtering (HiPIMS/DCMS) in Ar. The study focuses on the effect of HiPIMS plasma plumes on the cross-ionization of the material flux sputtered from the DCMS source. Al, Si, Ti, and Hf elemental targets are used to investigate the effect of the metal's first ionization potential IPMe1 and mass on the extent of cross-ionization. It is demonstrated that the interaction with HiPIMS plasma results in the significant ionization of the material flux sputtered from the DCMS source. Experiments conducted with elements of similar mass but having different IPMe1 values, Si and Al (Si-HiPIMS/Al-DCMS and Al-HiPIMS/Si-DCMS) reveal that the ionization of the DCMS flux is favored if the sputtered element has lower ionization potential than the one operating in the HiPIMS mode. If elements having similar IPMe1 are used on both sources, the metal mass becomes a decisive parameter as evidenced by experiments involving Ti and Hf (Ti-HiPIMS/Hf-DCMS and Hf-HiPIMS/Ti-DCMS). In such a case, Ti+ fluxes during Hf-HiPIMS/Ti-DCMS may even exceed Hf+ fluxes from the HiPIMS cathode and are much stronger than Hf+ fluxes during Ti-HiPIMS/Hf-DCMS. The latter effect can be explained by the fact that heavier Hf+ ions require longer transit time from the ionization zone to the substrate, which effectively increases the probability of interaction between the Hf-HiPIMS plasma plume and the Ti-DCMS flux, thereby leading to higher Ti ionization. Thus, the common notion of low ionization levels associated with DCMS has to be revised if DCMS is used together with highly ionized plasmas such as HiPIMS operating at higher peak target currents. These results are particularly important for the film growth in the hybrid configuration with substrate bias pulses synchronized to specific ion types.

  • 113.
    Svedberg, E B
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Birch, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Ivanov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Münger, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Sundgren, Jan- Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Asymmetric interface broadening in epitaxial Mo/W (001) superlattices grown by magnetron sputtering1998Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 16, nr 2, s. 633-638Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The interfacial structure in epitaxial Mo/W(001) superlattices, grown by magnetron sputtering on MgO(001) substrates has been studied. The films were grown in Ar and Kr discharges at a substrate temperature of 700 degrees C, and the as-deposited samples were analyzed by x-ray diffraction and found to be epitaxial with no high-angle grain boundaries. The degree of interfacial intermixing, caused by fluxes of different energetic species impinging on the growth surface, was estimated using a combination of Monte Carlo binary collision computer codes and a gas scattering computational model. In the Ar discharge case, large asymmetries in the Mo/W and W/Mo interfaces were found, with the W/Mo interface being more than a factor of 2 broader than the Mo/W interface. Simulations of x-ray reflectivity curves using the calculated interface profiles as input parameters without any additional fitting parameters agreed very well with measured data. The overall good fit between the calculated and measured reflectivity curves using the calculated compositional profiles is an indicator that the growth simulations using TRIM based codes provides interface profiles that are reasonably accurate, which can be used as a starting point for further refinements of the details of the interface structures. (C) 1998 American Vacuum Society.

  • 114.
    Tengstrand, Olof
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Nedfors, Nils
    Uppsala University, Sweden .
    Fast, Lars
    SP Technical Research Institute Sweden, Borås.
    Flink, Axel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan. Impact Coatings AB, Linköping, Sweden .
    Jansson, Ulf
    Uppsala University, Sweden .
    Eklund, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Structure and electrical properties of Nb-Ge-C nanocomposite coatings2014Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 32, nr 4, artikel-id 041509Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nb-Ge-C nanocomposite thin films were deposited by dc magnetron sputtering using three elemental targets. The films consist of substoichiometric NbCx in a nanometer-thick matrix of amorphous C and Ge. Films with no Ge contain grains that are elongated in the growth direction with a (111) preferred crystallographic orientation. With the addition of ∼12 at. % Ge, the grains are more equiaxed and exhibit a more random orientation. At even higher Ge contents, the structure also becomes denser. The porous structure of the low Ge content films result in O uptake from the ambient. With higher C content in the films both the amount of amorphous C and C/Nb-ratio increases. The contact resistance was measured by four-point technique as a function of contact force between 0 and 10 N. The lowest contact resistance (1.7 mΩ) is obtained at 10 N. The resistivity varies between 470 and 1700 μΩ·cm depending on porosity and O content.

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  • 115.
    Trinh, David Huy
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Andersson, Jon M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Collin, M.
    Sandvik Tooling, Stockholm, Sweden.
    Reineck, I.
    Sandvik Tooling, Stockholm, Sweden.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Radio frequency dual magnetron sputtering deposition and characterization of nanocomposite Al2O3-ZrO2 thin films2006Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 24, nr 2, s. 309-316Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Radio frequency magnetron sputtering from oxide targets has been used to synthesize crystalline alumina–zirconia nanocomposites at a relatively low temperature of 450  °C. Films of different compositions have been deposited ranging from pure zirconia to pure alumina, the compositions being measured with Rutherford backscattering and elastic recoil detection analysis. X-ray diffraction studies show the presence of the monoclinic zirconia phase in pure zirconia films. Addition of alumina into the film results in the growth of the cubic zirconia phase and amorphous alumina. No crystalline alumina was detected in either the composite or the pure alumina film. The microstructure of the films as studied by high resolution electron microscopy and scanning transmission electron microscopy shows a columnar growth mode in both the pure zirconia and nanocomposite films, but reveals differences in the intracolumnar structure. For the nanocomposite small equiaxed grains, ~5  nm in size, are found at the base of the columns at the interface with the substrate. An amorphous tissue of alumina was present between the small crystallites in the case of the nanocomposite.

  • 116.
    Urban, F. K.
    et al.
    Florida Int Univ, FL 33199 USA.
    Barton, D.
    Florida Int Univ, FL 33199 USA.
    Schubert, Mathias
    Univ Nebraska Lincoln, NE 68588 USA.
    Numerical ellipsometry: A method for selecting a single ß-gallium oxide monoclinic crystal orientation able to determine the complete permittivity tensor2023Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 41, nr 1, artikel-id 013402Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Previously, the infrared permittivity tensor of monoclinic beta-Ga2O3 crystals has been determined using ellipsometry reflection measurements from two differently oriented monoclinic beta-Ga2O3 crystals with surfaces parallel to (010) and (-201). The (010) surface places the crystallographic a-c plane in the table of the instrument. The permittivity tensor consists of four complex values, and in order to compute it, four or more combinations of measurements are required at selected table rotations and incidence angles. However, the (010) orientation also places the transverse optical (TO) modes with Au symmetry parallel to the z-axis of the instrument, and we find that these modes are not fully excited and, hence, not measurable due to underlying selection rules. This makes additional measurements on surfaces other than (010) necessary. The second orientation has been the (-201) crystal, which places the crystallographic b axis in the plane of the table to access the transverse Au phonons. In prior work, the overall tensor has been determined by combining measurements of the two crystal orientations [Schubert et al., Phys. Rev. B 93, 125209 (2016)]. The goal of the work here is to find single crystal orientations for which all TO modes can be determined from measurements. The use of a set of measurements employed for such a single crystal is inextricably linked to the choice of incidence angles and table rotations. Consequently, determining suitable angles for these is linked to the selection of a crystal orientation, which is, therefore, an integral part of the overall goal. The TO contribution to the permittivity strongly dominates at or near the TO mode wavenumber resonances and, therefore, are used in this work to identify suitable orientations for a single crystal. Any such crystal orientation will also provide measurements useful to compute permittivity across the entire measured wavenumber range. In principle, any crystal orientation that does not place the direction of any TO mode at or near the z-axis may be suitable due to the underlying physics and mathematics of the problem. We discuss which of these measurement parameters contain the most sensitivity for the (111) orientation. For accuracy, we seek the best or very good orientations. Our investigation follows a previously demonstrated approach where at a single wavelength, the full tensor of an orthorhombic absorbing crystal was obtained from a low-symmetry surface of stibnite [Schubert and Dollase, Opt. Lett. 27, 2073 (2002)]. We discuss which of these measurement parameters contain the most sensitivity for the (111) orientation. The methods presented here will also be useful for other monoclinic materials as well as other materials of different crystal structures, including orthorhombic and triclinic materials.

  • 117.
    Villamayor, Michelle M
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. Uppsala Univ, Sweden.
    Keraudy, Julien
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten. Oerlikon Balzers, Liechtenstein.
    Shimizu, Tetsuhide
    Tokyo Metropolitan Univ, Japan.
    Viloan, Rommel Paulo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Boyd, Robert
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Lundin, Daniel
    Univ Paris Saclay, France.
    Greene, Joseph E
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska fakulteten.
    Low temperature (T-s/T-m < 0.1) epitaxial growth of HfN/MgO(001) via reactive HiPIMS with metal-ion synchronized substrate bias2018Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 36, nr 6, artikel-id 061511Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Low-temperature epitaxial growth of refractory transition-metal nitride thin films by means of physical vapor deposition has been a recurring theme in advanced thin-film technology for several years. In the present study, 150-nm-thick epitaxial HfN layers are grown on MgO(001) by reactive high-power impulse magnetron sputtering (HiPIMS) with no external substrate heating. Maximum film-growth temperatures T-s due to plasma heating range from 70 to 150 degrees C, corresponding to T-s/T-m = 0.10-0.12 (in which T-m is the HfN melting point in K). During HiPIMS, gas and sputtered metal-ion fluxes incident at the growing film surface are separated in time due to strong gas rarefaction and the transition to a metal-ion-dominated plasma. In the present experiments, a negative bias of 100 V is applied to the substrate, either continuously during the entire deposition or synchronized with the metal-rich portion of the ion flux. Two different sputtering-gas mixtures, Ar/N-2 and Kr/N-2, are employed in order to probe effects associated with the noble-gas mass and ionization potential. The combination of x-ray diffraction, high-resolution reciprocal-lattice maps, and high-resolution cross-sectional transmission electron microscopy analyses establishes that all HfN films have a cube-on-cube orientational relationship with the substrate, i.e., [001](HfN)parallel to[001](MgO) and (100)(HfN)parallel to(100)(MgO). Layers grown with a continuous substrate bias, in either Ar/N-2 or Kr/N-2, exhibit a relatively high mosaicity and a high concentration of trapped inert gas. In distinct contrast, layers grown in Kr/N-2 with the substrate bias synchronized to the metal-ion-rich portion of HiPIMS pulses have much lower mosaicity, no measurable inert-gas incorporation, and a hardness of 25.7 GPa, in good agreement with the results for epitaxial HfN(001) layers grown at T-s = 650 degrees C (T-s/T-m = 0.26). The room-temperature film resistivity is 70 mu Omega cm, which is 3.2-10 times lower than reported values for polycrystalline-HfN layers grown at T-s = 400 degrees C. (c) 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

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  • 118.
    Wang, Xin
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Helmersson, Ulf
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik. Linköpings universitet, Tekniska högskolan.
    Madsen, Lynnette D
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Ivanov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Münger, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska högskolan.
    Rudner, Staffan
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Hjörvarsson, B
    Department of Physics, Uppsala University, Sweden.
    Sundgren, Jan-Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Composition, structure, and dielectric tunability of epitaxial SrTiO3 thin films grown by radio frequency magnetron sputtering1999Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 17, nr 2, s. 564-570Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Epitaxial (001) oriented SrTiO3 films have been deposited on LaAlO3(001) substrates by off-axis radio frequency magnetron sputtering in Ar:O-2 gas mixtures at substrate temperatures ranging from 650 to 850 degrees C. For the deposition conditions used, stoichiometric targets yielded 20% Sr-deficient films, whereas Sr-enriched targets (Sr1.1TiO0.9O3.0) resulted in stoichiometric films. The Sr-deficient films had a mosaic structure and a larger lattice parameter in comparison to bulk SrTiO3. The stoichiometric films on the other hand had a much higher crystalline quality in the as-deposited condition. The mosaicity of the latter films was primarily limited by the crystalline quality of the LaAlO3 substrates. The lattice parameters of the stoichiometric films were also smaller than the Sr-deficient ones and closer to the bulk value. The dielectric properties of the stoichiometric films were superior to the Sr-deficient films. For films with a thickness of similar to 300 nm, the typical dielectric constants as measured at similar to 77 K and I MHz were determined to be 820 and 500, for the stoichiometric and Sr-deficient films, respectively. Also the capacitance change, as a direct current bias voltage was applied to an interdigital capacitor, was higher for the stoichiometric film, 27.3% as compared to 8.6% when applying a bias of 300 V at 77 K. We also demonstrate the effectiveness of thermal annealing in improving both crystalline quality and dielectric properties, especially for the Sr-deficient films. (C) 1999 American Vacuum Society. [S0734-2101(99)010002-7].

  • 119.
    Watcharinyanon, Somsakul
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Johansson, Leif I.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Xia, Chao
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Virojanadara, Chariya
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ytterbium oxide formation at the graphene-SiC interface studied by photoemission2013Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 31, nr 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Synchrotron-based core level and angle resolved photoemission spectroscopy was used to study the formation of ytterbium (Yb) oxide at the graphene-SiC substrate interface. Oxide formation at the interface was accomplished in two steps, first intercalation of Yb into the interface region and then oxygen exposure while heating the sample at 260 degrees C to oxidize the Yb. After these processes, core level results revealed the formation of Yb oxide at the interface. The Yb 4f spectrum showed upon oxidation a clear valence change from Yb2+ to Yb3+. After oxidation the spectrum was dominated by emission from oxide related Yb3+ states and only a small contribution from silicide Yb2+ states remained. In addition, the very similar changes observed in the oxide related components identified in the Si 2p and Yb 4f spectra after oxidation and after subsequent heating suggested formation of a Si-Yb-O silicate at the interface. The electronic band structure of graphene around the (K) over bar -point was upon Yb intercalation found to transform from a single pi band to two pi bands. After Yb oxide formation, an additional third pi band was found to appear. These pi bands showed different locations of the Dirac point (E-D), i.e., two upper bands with E-D around 0.4 eV and a lower band with E-D at about 1.5 eV below the Fermi level. The appearance of three pi-bands is attributed to a mixture of areas with Yb oxide and Yb silicide at the interface.

  • 120.
    Wu, Zhengtao
    et al.
    Guangdong Univ Technol, Peoples R China.
    Tengstrand, Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakhit, Babak
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Greene, Joseph E
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA; Natl Taiwan Univ Sci and Technol, Taiwan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Petrov, Ivan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten. Univ Illinois, IL 61801 USA.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Growth of dense, hard yet low-stress Ti0.40Al0.27W0.33N nanocomposite films with rotating substrate and no external substrate heating2020Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 38, nr 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    W+ irradiation of TiAlN is used to demonstrate growth of dense, hard, and stress-free refractory nitride coatings with no external heating during reactive magnetron sputtering. Ti0.40Al0.27W0.33N nanocomposite films are deposited on Si(001) substrates using hybrid high-power impulse and dc magnetron cosputtering (HiPIMS and DCMS) in an industrial sputtering system employing substrate rotation during film growth from six cathodes. Two W targets powered by HiPIMS serve as a pulsed source of energetic W+ ions with incident fluxes analyzed by in situ time- and energy-resolved mass spectroscopy, while the remaining four targets (two elemental Ti targets and two Ti plates with Al plugs) are operated in the DCMS mode (W-HiPIMS/TiAl-DCMS) to provide a continuous flux of metal atoms and sustain a high deposition rate. A negative substrate bias V-s is applied only in synchronous with the W+-ion-rich portion of each HiPIMS pulse in order to provide film densification by heavy-ion irradiation of the TiAlN layers deposited between W+-ion exposures. W is selected for densification due to its high mass and relatively low reactivity with N-2, thus minimizing target poisoning while enhancing gas rarefaction. Dense Ti0.40Al0.27W0.33N alloy films, grown with no external substrate heating (substrate temperature T-s lower than 150 degrees C due to heat load from the plasma) and V-s=500V, exhibit a nanoindentation hardness of H=23.1GPa and an elastic modulus of E=378GPa, which are, respectively, 210% and 40% higher than for reference underdense DCMS Ti0.58Al0.42N films grown under the same conditions, but without W+ irradiation. The W ion bombardment does not affect the film stress state, which is compressive and low at 1.2GPa.

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  • 121.
    Zarshenas, Mohammad
    et al.
    Fraunhofer Inst Mech Mat IWM, Germany; Univ Freiburg, Germany.
    Sangiovanni, Davide
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Sarakinos, Kostas
    Univ Helsinki, Finland; KTH Royal Inst Technol, Sweden.
    Diffusion and magnetization of metal adatoms on single-layer molybdenum disulfide at elevated temperatures2024Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 42, nr 2, artikel-id 023409Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present work models temperature-dependent ( 500-1300K) diffusion dynamics of Ag, Au, and Cu adatoms on MoS2 as well as electronic and magnetic properties of adatom (Ag, Au, and Cu)/MoS2 systems. Modeling is done by means of ab initio molecular dynamics (AIMD) simulations that account for van der Waals corrections and electronic spin degrees of freedom in the framework of density functional theory. It is found that Ag and Au adatoms exhibit super-diffusive motion on MoS2 at all temperatures, while Cu adatoms follow a random walk pattern of uncorrelated surface jumps. The observed behavior is consistent with AIMD-calculated effective migration barriers Ea ( EaAg=190 +/- 50meV, EaAu=67 +/- 7meV, and EaCu=300 +/- 100meV) and can be understood on the basis of the considerably flatter potential energy landscapes encountered by Ag and Au adatoms on the MoS2 surface (corrugation of the order of tens of meV), as compared to Cu adatoms (corrugation &gt;100meV). Moreover, evaluation of the electronic and magnetic properties of AIMD configurations suggest that Ag, Au, and Cu monomer adsorption induces semimetallic features in at least one spin channel of the adatom/MoS2 electronic structure at elevated temperatures. The overall results presented herein may provide insights into fabricating 2D-material-based heterostructure devices beyond graphene

  • 122.
    Zhu, Jianqiang
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Eriksson, Anders O.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Ghafoor, Naureen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Greczynski, Grzegorz
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Rosén, Johanna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Microstructure evolution of Ti3SiC2 compound cathodes during reactive cathodic arc evaporation2011Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 29, nr 3, s. 031601-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The microstructure evolution and compositional variation of Ti3SiC2 cathode surfaces during reactive cathodic arc evaporation are presented for different process conditions. The results show that phase decomposition takes place in the near-surface region, resulting in a 5-50 mu m thick converted layer that is affected by the presence of nitrogen in the deposition chamber. This layer consists of two different sublayers, i.e., 1-20 mu m thick top layer with a melted and resolidified microstructure, followed by a 4-30 mu m thick transition layer with a decomposed microstructure. The converted layer contains a polycrystalline TiCx phase and trace quantities of Si-rich domains with Ti5Si3(C) at their interface. The arc discharge causes Si redistribution in the two regions of the layer, whose Si/(Ti+Si) ratio is higher in the top region and lower in the transition region compared to the virgin material.

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  • 123.
    Zhu, Jianqiang
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Syed, Muhammad Bilal
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Polcik, Peter
    PLANSEE Composite Materials GmbH, Germany.
    Håkansson, G.
    Ionbond Sweden AB, Linköping, Swedeb.
    Johansson Jöesaar, Mats P.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan. Seco Tools, Fagersta, Sweden.
    Ahlgren, M.
    Sandvik Coromant, Stockholm, Sweden.
    Odén, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Nanostrukturerade material. Linköpings universitet, Tekniska högskolan.
    Effects of cathode grain size and substrate fixturing on the microstructure evolution of arc evaporated Cr-cathodes and Cr-N coating synthesis2014Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 32, nr 2, s. 021515-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of the cathode grain size and the substrate fixturing on the microstructure evolution of the Cr cathodes and the resulting Cr-N coating synthesis is studied. Hot isostatic pressed Cr cathodes with three different grain sizes were arc evaporated in a nitrogen atmosphere and Cr-N coatings were deposited on cemented carbide substrate at 2 and 4 Pa nitrogen pressure, respectively. The Cr cathodes before and after arc discharging are composed of polycrystalline α-Cr regardless of the grain size. A converted layer forms on the Cr cathode surface and its microstructure differs with the cathode grain size. A stationary substrate fixturing results in ditches covering the cathode surface while a single rotating fixturing does not. The increased grain size of the virgin Cr cathodes enhances the quantities of the ditches. The possible causes are addressed. At 2 Pa nitrogen pressure, the Cr-N coatings deposited with the single rotating fixturing comprise only cubic CrN phase while the ones deposited with the stationary fixturing contain a mixture of hexagonal Cr2N and cubic CrN phases. By the increasing grain size of the Cr cathode, the droplet density of the Cr-N coatings increase somewhat while the hardness decreases for the Cr-N coatings deposited with stationary fixturing at 2 Pa nitrogen pressure.

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