Simulation of linear magnetron discharges in 2D and 3D

Pflug, Andreas; Siemers, Michael; Melzig, Thomas; Schäfer, Lothar; Bräuer, Günter

doi:10.1016/j.surfcoat.2014.09.042

Cited by 36 publications

(21 citation statements)

References 13 publications

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“…Most closely related to our experimental results is modeling of low current DCMS discharges performed by Pflug et al 63 and Siemers et al 64 They showed the formation of traveling ionization zones by using Particle-in-Cell (PIC) simulations and obtained a similar plasma potential distribution as measured in our experiments (cf. 45 investigated the effect of spokes and their potential distribution on the particle transport for HiPIMS discharges.…”

Section: E Comparison Of Potential Measurements With Simulations Frosupporting

confidence: 88%

Plasma potential of a moving ionization zone in DC magnetron sputtering

Panjan

Anders

2017

Journal of Applied Physics

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Using movable emissive and floating probes, we determined the plasma and floating potentials of an ionization zone (spoke) in a direct current magnetron sputtering discharge. Measurements were recorded in a space and time resolved manner, which allowed us to make a three-dimensional representation of the plasma potential. From this information we could derive the related electric field, space charge, and the related spatial distribution of electron heating. The data reveal the existence of strong electric fields parallel and perpendicular to the target surface. The largest E-fields result from a double layer structure at the leading edge of the ionization zone. We suggest that the double layer plays a crucial role in the energization of electrons since electrons can gain several 10 eV of energy when crossing the double layer. We find sustained coupling between the potential structure, electron heating, and excitation and ionization processes as electrons drift over the magnetron target. The brightest region of an ionization zone is present right after the potential jump, where drifting electrons arrive and where most local electron heating occurs. The ionization zone intensity decays as electrons continue to drift in the Ez × B direction, losing energy by inelastic collisions; electrons become energized again as they cross the potential jump. This results in the elongated, arrowhead-like shape of the ionization zone. The ionization zone moves in the –Ez × B direction from which the to-be-heated electrons arrive and into which the heating region expands; the zone motion is dictated by the force of the local electric field on the ions at the leading edge of the ionization zone. We hypothesize that electron heating caused by the potential jump and physical processes associated with the double layer also apply to magnetrons at higher discharge power, including high power impulse magnetron sputtering.

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Section: E Comparison Of Potential Measurements With Simulations Frosupporting

confidence: 88%

Plasma potential of a moving ionization zone in DC magnetron sputtering

Panjan

Anders

2017

Journal of Applied Physics

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“…However, several publications report on spokes propagating in the opposite, retrograde × E B direction. This trend has been observed experimentally in magnetic micro-discharges [8] and in magnetron plasmas [9], and as an outcome of a particle-in-cell Monte-Carlo simulation method of a magnetron plasma [10]. Ito and Cappelli [8] suggested that the retrograde rotation is due to fluctuations in plasma density, which they attribute to drift waves driven by density gradients.…”

Section: Introductionmentioning

confidence: 57%

Spoke rotation reversal in magnetron discharges of aluminium, chromium and titanium

Hecimovic

Maszl

Gathen

et al. 2016

Plasma Sources Sci. Technol.

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The rotation of localised ionisation zones, i.e. spokes, in magnetron discharge are frequently observed. The spokes are investigated by measuring floating potential oscillations with 12 flat probes placed azimuthally around a planar circular magnetron. The 12-probe setup provides sufficient temporal and spatial resolution to observe the properties of various spokes, such as rotation direction, mode number and angular velocity. The spokes are investigated as a function of discharge current, ranging from 10 mA (current density 0.5 mA cm −2) to 140 A (7 A cm −2). In the range from 10 mA to 600 mA the plasma was sustained in DC mode, and in the range from 1 A to 140 A the plasma was pulsed in high-power impulse magnetron sputtering mode. The presence of spokes throughout the complete discharge current range indicates that the spokes are an intrinsic property of a magnetron sputtering plasma discharge. The spokes may disappear at discharge currents above 80 A for Cr, as the plasma becomes homogeneously distributed over the racetrack. Up to discharge currents of several amperes (the exact value depends on the target material), the spokes rotate in a retrograde × E B direction with angular velocity in the range of 0.2-4 km s −1. Beyond a discharge current of several amperes, the spokes rotate in a × E B direction with angular velocity in the range of 5-15 km s −1. The spoke rotation reversal is explained by a transition from Ar-dominated to metal-dominated sputtering that shifts the plasma emission zone closer to the target. The spoke itself corresponds to a region of high electron density and therefore to a hump in the electrical potential. The electric field around the spoke dominates the spoke rotation direction. At low power, the plasma is further away from the target and it is dominated by the electric field to the anode, thus retrograde × E B rotation. At high power, the plasma is closer to the target and it is dominated by the electric field pointing to the target, thus × E B rotation.

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“…As an example it is possible to realistically describe the so called cross corner effect in magnetron sputtering, which is an enhanced erosion of linear sputter targets close to the corner region, by low-density PIC-MC simulation as shown in [11]. While PIC-MC simulations of magnetron discharges at higher plasma density become feasible in two dimensions [12] it is shown that three-dimensional magnetron discharges are characterized by propagating ionization waves which cannot be described within two dimensional models by definition [13]. Such ionization waves can also be experimentally observed either at very low discharge currents [14] or also under high plasma density conditions [15], and they can have an impact on the energy distribution of positive ions [16].…”

Section: Transport Simulations Applying Dsmc/picmcmentioning

confidence: 99%

Simulation in thin film technology

et al. 2015

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Braunschweig, Germany ABSTRACTSimulation and modeling find more and more their way into thin film technology. Beside theoretical models for layer design, pre-production design analysis, and real time process control, atomistic simulation techniques gain of importance. Here, especially classical procedures such as Direct Simulation and Particle-in-Cell Monte Carlo (DSMC/PIC-MC), kinetic Monte Carlo (kMC) and Molecular Dynamics (MD) as well as quantum mechanical techniques based on Density Functional Theory (DFT) have to be mentioned. These methods are applied in order to investigate the material transport inside the coating facilities, the thin film growth in dependence of characteristic process conditions, and the optical and electronic thin film properties. By combination of these atomistic techniques in a suitable manner, a multiple scale simulation model can be realized for investigating the influence of specific process conditions on the resulting layer properties. The further extension of this "virtual coater" concept with respect to rate equation models enables the possibility to investigate also the interaction of laser irradiation with the modeled thin film structures.

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Simulation of linear magnetron discharges in 2D and 3D

Cited by 36 publications

References 13 publications

Plasma potential of a moving ionization zone in DC magnetron sputtering

Plasma potential of a moving ionization zone in DC magnetron sputtering

Spoke rotation reversal in magnetron discharges of aluminium, chromium and titanium

Simulation in thin film technology

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