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Diederik Depla - One of the best experts on this subject based on the ideXlab platform.
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tutorial hysteresis during the Reactive magnetron Sputtering process
Journal of Applied Physics, 2018Co-Authors: Koen Strijckmans, Roeland Schelfhout, Diederik DeplaAbstract:Reactive magnetron Sputtering is a well-established physical vapor technique to deposit thin compound films on different substrates, ranging from insulating glass windows over wear-resistant car parts to high-responsive touch screens. In this way, the industrial and technological relevance drives the need to understand this process on a more profound level to make optimal use of it. Notwithstanding, the basic principles of the technique can be summarized on a single sheet of paper, and truly mastering and understanding the process behavior is not a simple task. One of the main reasons is the often strong non-linear response of the Reactive system to changes in the operation parameters or to small system fluctuations. This aspect of Reactive Sputtering is embodied by the occurrence of a hysteresis in the system observables as a function of the operation parameters. It is the existence of the hysteresis that troubles optimal deposition and process control on the one hand and gives voice to the intertwined physical and chemical complexity on the other hand. The aim of this tutorial can be considered as threefold: to acquaint the reader with an insight into the concept of the hysteresis during Reactive Sputtering, to touch some of the possibilities to eliminate the hysteresis, and finally, to present how to control this hysteresis in a stable operative sense. To this end, the Reactive magnetron Sputtering process will be formulated in practical parameters and by two discriminating phenomenological global models: the original Berg model and the Reactive Sputtering deposition (RSD) model. The Reactive Sputtering of Al in an O 2/Ar atmosphere under direct discharge current control will be used as a reference system. The models are able to describe the hysteresis effects, giving an insight into their origin and the possibilities to eliminate them. The discharge description can, in this context, be reduced to the current/voltage or I V-characteristic and its response to a changing target state. The tutorial concludes with the existence of a double hysteresis effect and an explanation based on the RSD model.
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tutorial hysteresis during the Reactive magnetron Sputtering process
Journal of Applied Physics, 2018Co-Authors: Koen Strijckmans, Roeland Schelfhout, Diederik DeplaAbstract:Reactive magnetron Sputtering is a well-established physical vapor technique to deposit thin compound films on different substrates, ranging from insulating glass windows over wear-resistant car parts to high-responsive touch screens. In this way, the industrial and technological relevance drives the need to understand this process on a more profound level to make optimal use of it. Notwithstanding, the basic principles of the technique can be summarized on a single sheet of paper, and truly mastering and understanding the process behavior is not a simple task. One of the main reasons is the often strong non-linear response of the Reactive system to changes in the operation parameters or to small system fluctuations. This aspect of Reactive Sputtering is embodied by the occurrence of a hysteresis in the system observables as a function of the operation parameters. It is the existence of the hysteresis that troubles optimal deposition and process control on the one hand and gives voice to the intertwined physical and chemical complexity on the other hand. The aim of this tutorial can be considered as threefold: to acquaint the reader with an insight into the concept of the hysteresis during Reactive Sputtering, to touch some of the possibilities to eliminate the hysteresis, and finally, to present how to control this hysteresis in a stable operative sense. To this end, the Reactive magnetron Sputtering process will be formulated in practical parameters and by two discriminating phenomenological global models: the original Berg model and the Reactive Sputtering deposition (RSD) model. The Reactive Sputtering of Al in an O 2/Ar atmosphere under direct discharge current control will be used as a reference system. The models are able to describe the hysteresis effects, giving an insight into their origin and the possibilities to eliminate them. The discharge description can, in this context, be reduced to the current/voltage or I V-characteristic and its response to a changing target state. The tutorial concludes with the existence of a double hysteresis effect and an explanation based on the RSD model.Reactive magnetron Sputtering is a well-established physical vapor technique to deposit thin compound films on different substrates, ranging from insulating glass windows over wear-resistant car parts to high-responsive touch screens. In this way, the industrial and technological relevance drives the need to understand this process on a more profound level to make optimal use of it. Notwithstanding, the basic principles of the technique can be summarized on a single sheet of paper, and truly mastering and understanding the process behavior is not a simple task. One of the main reasons is the often strong non-linear response of the Reactive system to changes in the operation parameters or to small system fluctuations. This aspect of Reactive Sputtering is embodied by the occurrence of a hysteresis in the system observables as a function of the operation parameters. It is the existence of the hysteresis that troubles optimal deposition and process control on the one hand and gives voice to the intertwined p...
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Modeling target erosion during Reactive Sputtering
Applied Surface Science, 2015Co-Authors: Koen Strijckmans, Diederik DeplaAbstract:Abstract The influence of the Reactive sputter conditions on the racetrack and the sputter profile for an Al/O2 DC Reactive sputter system is studied by modeling. The role of redeposition, i.e. the deposition of sputtered material back on the target, is therefore taken into account. The used model RSD2013 is capable of simulating the effect of redeposition on the target condition in a spatial resolved way. Comparison between including and excluding redeposition in the RSD2013 model shows that the in-depth oxidation profile of the target differs. Modeling shows that it is important to distinguish between the formed racetrack, i.e. the erosion depth profile, and the sputter profile. The latter defines the distribution of the sputtered atoms in the vacuum chamber. As the target condition defines the sputter yield, it does determine the racetrack and the sputter profile of the planar circular target. Both the shape of the racetrack and the sputter profile change as function of the redeposition fraction as well as function of the oxygen flow change. Clear asymmetries and narrowing are observed for the racetrack shape. Similar effects are noticed for the sputter profile but to a different extent. Based on this study, the often heard misconception that the racetrack shape defines the distribution of the sputtered atoms during Reactive Sputtering is proven to be wrong.
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high rate Reactive magnetron sputter deposition of titanium oxide
Applied Physics Letters, 2008Co-Authors: Tomas Kubart, Diederik Depla, Tomas Nyberg, D S Martin, Sören BergAbstract:A systematic experimental study of Reactive Sputtering from substoichiometric targets of TiOx with x ranging from 0 to 1.75 is reported. Experimental results are compared with results from modeling. The developed model describes the observed behavior and explains the origins of the unexpectedly high deposition rate. The behavior is shown to originate from the presence of titanium suboxides at the target surface caused by preferential Sputtering of the oxide. The model can be used for optimization of the target composition with respect to the deposition rate and film composition in a stable hysteresis-free Reactive Sputtering process.
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understanding the discharge voltage behavior during Reactive Sputtering of oxides
Journal of Applied Physics, 2007Co-Authors: Diederik Depla, J Haemers, S Heirwegh, Stijn Mahieu, R. De GryseAbstract:The discharge voltage was measured for 15 different metallic target materials at constant current before and after plasma oxidation in order to understand its behavior during Reactive magnetron Sputtering. Plasma oxidation of the target surface was achieved by Sputtering the target in pure oxygen. The discharge voltage measured in pure argon is characteristic for each kind of metallic target and is related to the ion induced secondary electron emission (ISEE) coefficient of the target material. Based on this relation a value for the ISEE coefficient of the oxidized target surface can be calculated. Two distinct groups can be discerned: for one group the ISEE coefficient of the oxidized target surface is larger than the ISEE coefficient of the metal, while the opposite behavior is noticed for the second group. This difference seems to find its origin in the reduction behavior of the oxides under ion bombardment, since the ISEE coefficient of the oxide can be related to the simulated degree of reduction of ...
Sören Berg - One of the best experts on this subject based on the ideXlab platform.
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upgrading the berg model for Reactive Sputtering processes
Thin Solid Films, 2014Co-Authors: Sören Berg, Erik Sarhammar, Tomas NybergAbstract:Several phenomena are neglected in the original “Berg model” in order to provide a simple model of the Reactive Sputtering process. There exist situations, however, where this simplified treatment ...
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the influence of total processing pressure on the hysteresis behaviour in Reactive Sputtering
18th International Vaccum Congress (IVC-18) Beijing August 23-27 2010, 2010Co-Authors: Erik Sarhammar, Tomas Nyberg, Sören BergAbstract:The influence of total processing pressure on the hysteresis behaviour in Reactive Sputtering
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high rate Reactive magnetron sputter deposition of titanium oxide
Applied Physics Letters, 2008Co-Authors: Tomas Kubart, Diederik Depla, Tomas Nyberg, D S Martin, Sören BergAbstract:A systematic experimental study of Reactive Sputtering from substoichiometric targets of TiOx with x ranging from 0 to 1.75 is reported. Experimental results are compared with results from modeling. The developed model describes the observed behavior and explains the origins of the unexpectedly high deposition rate. The behavior is shown to originate from the presence of titanium suboxides at the target surface caused by preferential Sputtering of the oxide. The model can be used for optimization of the target composition with respect to the deposition rate and film composition in a stable hysteresis-free Reactive Sputtering process.
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dynamic behaviour of the Reactive Sputtering process
Thin Solid Films, 2006Co-Authors: Tomas Kubart, Tomas Nyberg, Oliver Kappertz, Sören BergAbstract:Modelling of the dynamic behaviour of the Reactive Sputtering process is a key issue in many respects. Apart from increasing the basic understanding, such a model is also important for an active control of the process so that optimal deposition conditions can be maintained. This work is intended to present a basic model for the dynamic behaviour of the Reactive Sputtering process. The influence of the processing parameters on the transient behaviour is discussed. We found that the processing curves depend on the rate by which the processing parameters are varied. In particular, when measuring pressure–flow curves for increasing and decreasing Reactive gas flow, the rate of change of the Reactive gas supply strongly influences the width of the hysteresis region.
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process stabilization and increase of the deposition rate in Reactive Sputtering of metal oxides and oxynitrides
Applied Physics Letters, 2006Co-Authors: Daniel Severin, Sören Berg, Tomas Kubart, Tomas Nyberg, Oliver Kappertz, Andreas Pflug, Michael Siemers, Matthias WuttigAbstract:Reactive Sputtering processes normally exhibit undesirable hysteresis effects which are more pronounced for oxide than nitride deposition. We present a method to reduce and ultimately eliminate these effects for Reactive Sputtering of metal oxides and oxynitrides. This is achieved by the addition of nitrogen to the oxygen process, which in addition leads to a higher deposition rate. These observations can be qualitatively explained and theoretically predicted using an extension of the Berg's model to two different Reactive gases. Although the nitrogen addition leads to pronounced changes of the processing characteristics, incorporation of nitrogen into the growing film is very small.
Tomas Nyberg - One of the best experts on this subject based on the ideXlab platform.
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upgrading the berg model for Reactive Sputtering processes
Thin Solid Films, 2014Co-Authors: Sören Berg, Erik Sarhammar, Tomas NybergAbstract:Several phenomena are neglected in the original “Berg model” in order to provide a simple model of the Reactive Sputtering process. There exist situations, however, where this simplified treatment ...
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the influence of total processing pressure on the hysteresis behaviour in Reactive Sputtering
18th International Vaccum Congress (IVC-18) Beijing August 23-27 2010, 2010Co-Authors: Erik Sarhammar, Tomas Nyberg, Sören BergAbstract:The influence of total processing pressure on the hysteresis behaviour in Reactive Sputtering
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high rate Reactive magnetron sputter deposition of titanium oxide
Applied Physics Letters, 2008Co-Authors: Tomas Kubart, Diederik Depla, Tomas Nyberg, D S Martin, Sören BergAbstract:A systematic experimental study of Reactive Sputtering from substoichiometric targets of TiOx with x ranging from 0 to 1.75 is reported. Experimental results are compared with results from modeling. The developed model describes the observed behavior and explains the origins of the unexpectedly high deposition rate. The behavior is shown to originate from the presence of titanium suboxides at the target surface caused by preferential Sputtering of the oxide. The model can be used for optimization of the target composition with respect to the deposition rate and film composition in a stable hysteresis-free Reactive Sputtering process.
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dynamic behaviour of the Reactive Sputtering process
Thin Solid Films, 2006Co-Authors: Tomas Kubart, Tomas Nyberg, Oliver Kappertz, Sören BergAbstract:Modelling of the dynamic behaviour of the Reactive Sputtering process is a key issue in many respects. Apart from increasing the basic understanding, such a model is also important for an active control of the process so that optimal deposition conditions can be maintained. This work is intended to present a basic model for the dynamic behaviour of the Reactive Sputtering process. The influence of the processing parameters on the transient behaviour is discussed. We found that the processing curves depend on the rate by which the processing parameters are varied. In particular, when measuring pressure–flow curves for increasing and decreasing Reactive gas flow, the rate of change of the Reactive gas supply strongly influences the width of the hysteresis region.
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process stabilization and increase of the deposition rate in Reactive Sputtering of metal oxides and oxynitrides
Applied Physics Letters, 2006Co-Authors: Daniel Severin, Sören Berg, Tomas Kubart, Tomas Nyberg, Oliver Kappertz, Andreas Pflug, Michael Siemers, Matthias WuttigAbstract:Reactive Sputtering processes normally exhibit undesirable hysteresis effects which are more pronounced for oxide than nitride deposition. We present a method to reduce and ultimately eliminate these effects for Reactive Sputtering of metal oxides and oxynitrides. This is achieved by the addition of nitrogen to the oxygen process, which in addition leads to a higher deposition rate. These observations can be qualitatively explained and theoretically predicted using an extension of the Berg's model to two different Reactive gases. Although the nitrogen addition leads to pronounced changes of the processing characteristics, incorporation of nitrogen into the growing film is very small.
Tomas Kubart - One of the best experts on this subject based on the ideXlab platform.
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Reactive Sputtering of precursors for cu2znsns4 thin film solar cells
Thin Solid Films, 2012Co-Authors: Tove Ericson, Tomas Kubart, Jonathan J Scragg, Charlotte PlatzerbjorkmanAbstract:The quaternary semiconductor Cu2ZnSnS4 (CZTS) is a possible In-free replacement for Cu(In,Ga)Se-2. Here we present Reactive Sputtering with the possibility to obtain homogeneous CZTS-precursors wit ...
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high rate Reactive magnetron sputter deposition of titanium oxide
Applied Physics Letters, 2008Co-Authors: Tomas Kubart, Diederik Depla, Tomas Nyberg, D S Martin, Sören BergAbstract:A systematic experimental study of Reactive Sputtering from substoichiometric targets of TiOx with x ranging from 0 to 1.75 is reported. Experimental results are compared with results from modeling. The developed model describes the observed behavior and explains the origins of the unexpectedly high deposition rate. The behavior is shown to originate from the presence of titanium suboxides at the target surface caused by preferential Sputtering of the oxide. The model can be used for optimization of the target composition with respect to the deposition rate and film composition in a stable hysteresis-free Reactive Sputtering process.
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dynamic behaviour of the Reactive Sputtering process
Thin Solid Films, 2006Co-Authors: Tomas Kubart, Tomas Nyberg, Oliver Kappertz, Sören BergAbstract:Modelling of the dynamic behaviour of the Reactive Sputtering process is a key issue in many respects. Apart from increasing the basic understanding, such a model is also important for an active control of the process so that optimal deposition conditions can be maintained. This work is intended to present a basic model for the dynamic behaviour of the Reactive Sputtering process. The influence of the processing parameters on the transient behaviour is discussed. We found that the processing curves depend on the rate by which the processing parameters are varied. In particular, when measuring pressure–flow curves for increasing and decreasing Reactive gas flow, the rate of change of the Reactive gas supply strongly influences the width of the hysteresis region.
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process stabilization and increase of the deposition rate in Reactive Sputtering of metal oxides and oxynitrides
Applied Physics Letters, 2006Co-Authors: Daniel Severin, Sören Berg, Tomas Kubart, Tomas Nyberg, Oliver Kappertz, Andreas Pflug, Michael Siemers, Matthias WuttigAbstract:Reactive Sputtering processes normally exhibit undesirable hysteresis effects which are more pronounced for oxide than nitride deposition. We present a method to reduce and ultimately eliminate these effects for Reactive Sputtering of metal oxides and oxynitrides. This is achieved by the addition of nitrogen to the oxygen process, which in addition leads to a higher deposition rate. These observations can be qualitatively explained and theoretically predicted using an extension of the Berg's model to two different Reactive gases. Although the nitrogen addition leads to pronounced changes of the processing characteristics, incorporation of nitrogen into the growing film is very small.
A J Flewitt - One of the best experts on this subject based on the ideXlab platform.
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spectroscopic ellipsometry characterization of zno sn thin films with various sn composition deposited by remote plasma Reactive Sputtering
Applied Surface Science, 2017Co-Authors: Petr Janicek, Kham M Niang, Jan Mistrik, Karel Palka, A J FlewittAbstract:Abstract ZnO:Sn thin films were deposited onto thermally oxidized silicon substrates using a remote plasma Reactive Sputtering. Their optical constants (refractive index n and extinction coefficient k) were determined from ellipsometric data recorded over a wide spectral range (0.05–6 eV). Parametrization of ZnO:Sn complex dielectric permittivity consists of a parameterized semiconductor oscillator function describing the short wavelength absorption edge, a Drude oscillator describing free carrier absorption in near-infrared part of spectra and a Lorentz oscillator describing the long wavelength absorption edge and intra-band absorption in the ultra-violet part of the spectra. Using a Mott-Davis model, the increase in local disorder with increasing Sn doping is quantified from the short wavelength absorption edge onset. Using the Wemple-DiDomenico single oscillator model for the transparent part of the optical constants spectra, an increase in the centroid distance of the valence and conduction bands with increasing Sn doping is shown and only slight increase in intensity of the inter-band optical transition due to Sn doping occurs. The Drude model applied in the near-infrared part of the spectra revealed the free carrier concentration and mobility of ZnO:Sn. Results show that the range of transparency of prepared ZnO:Sn layers is not dramatically affected by Sn doping whereas electrical conductivity could be controlled by Sn doping. Refractive index in the transparent part is comparable with amorphous Indium Gallium Zinc Oxide allowing utilization of prepared ZnO:Sn layers as an indium-free alternative.
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Zinc tin oxide thin film transistors produced by a high rate Reactive Sputtering: Effect of tin composition and annealing temperatures
'Royal College of Obstetricians & Gynaecologists (RCOG)', 2017Co-Authors: Km Niang, Cho J, Sadhanala A, Wi Milne, Rh Friend, A J FlewittAbstract:Amorphous zinc tin oxides (a-ZTO), which are stoichiometrically close to the Zn$_2$SnO$_4$ and ZnSnO$_3$ phases, have been deposited using remote-plasma Reactive Sputtering, and incorporated as the channel layers in thin film transistors (TFTs). The influence of tin composition and annealing temperatures on the structural and phase evolutions of the thin films, and the electrical performances of the TFTs are investigated. Zn$_2$SnO$_4$ exhibited randomly oriented polycrystalline peaks at annealing temperatures ≥700 °C, while ZnSnO$_3$ decomposed into Zn$_2$SnO$_4$ and SnO$_2$ at 950 °C. TFTs employing a Zn$_2$SnO$_4$ channel, after a post-deposition annealing at 500 °C, exhibited a field effect mobility ~14 cm$^2$ V$^{−1}$ s$^{−1}$ and a sub-threshold slope ~0.6 V dec$^{−1}$. When the tin content was increased in the channel, as in ZnSnO$_3$, TFTs exhibited an increase in field effect mobility ~20 cm$^2$ V$^{−1}$ s$^{−1}$, but with a slight deterioration of sub-threshold slope to ~0.8 V dec$^{−1}$. When the post-deposition annealing temperature was reduced to 300 °C, a mobility as high as ~10 cm$^2$ V$^{−1}$ s$^{−1}$ was still achieved, however, a significant shoulder in the IDS–VGS curve, together with a higher off-state current was observed. TFT characteristics are explained by the sub-bandgap defect states measured by photothermal deflection spectroscopy and the extracted Urbach energies
