Two-Dimensional Double Probe Study of the Temporal Evolution of the Charge Carrier Density in a Pulsed Magnetron

Welzel, Thomas; Dunger, Thoralf; Richter, Frank

doi:10.1002/ppap.200732302

Cited by 6 publications

(2 citation statements)

References 29 publications

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“…The frequency ω of the fast changes in the potential is about 50 MHz. Then a response time in front of the target in the 7 magnetic trap of ∼10 ns (taking n = 5 × 10 11 cm −3 [27], T e = 5 eV) and in front of the substrate of ∼ 500 ns (taking n = 5 × 10 9 cm −3 [28], T e = 2 eV) is obtained, which is of the order of magnitude that we observed (cf figure 3). Importantly, it should be noted that the estimation shows that the response time is strongly dependent on the charge carrier density n of the local plasma.…”

Section: Methodssupporting

confidence: 56%

Spatial and temporal development of the plasma potential in differently configured pulsed magnetron discharges

Welzel¹,

Dunger

Liebig

et al. 2008

New J. Phys.

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T h e o p e n -a c c e s s j o u r n a l f o r p h y s i c s Abstract. Time-resolved emissive probe measurements have been performed to study the spatio-temporal development of the plasma potential in an asymmetric bipolar pulsed magnetron discharge. The influence of the substrate potential as well as of the substrate position has been investigated while the further conditions were the same. To access the entire potential range which was between −100 V and + 400 V and to obtain sufficient time-resolution of the emissive probe, different heating currents had to be used. The plasma potential has been found to be typically close to zero in the 'on' phase, about + 40 V in the stable 'off' phase and up to + 400 V at the beginning of the 'off' phase, which is in agreement with the results of other authors. However, the positive values in the 'off' phase are generally lower than those reported and stay mostly below the target potential. This is explained by macroscopic considerations of the quasineutrality of the plasma taking into account a magnetic and geometrical shielding of the target, acting as an anode in the 'off' phase, and the potential and position of the substrate holder and environment. New Journal of Physics

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Section: Methodssupporting

confidence: 56%

Spatial and temporal development of the plasma potential in differently configured pulsed magnetron discharges

Welzel¹,

Dunger

Liebig

et al. 2008

New J. Phys.

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show abstract

“…Optical emission spectroscopy substantiated the existence of temporal density increases or high energetic electrons at these times [21,22,27]; the latter, however, could not be detected with the double probe. A spatial survey of the two maxima revealed that they were differently pronounced throughout the discharge volume [28]. The first was most intense in the bulk plasma above the magnetic null of the magnetron where most of the residual electrons which are considered uniformly distributed were accelerated.…”

Section: Energetic Spikes In T Ementioning

confidence: 99%

Physics and phenomena in pulsed magnetrons: an overview

Bradley¹,

Welzel²

2009

J. Phys. D: Appl. Phys.

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This paper reviews the contribution made to the observation and understanding of the basic physical processes occurring in an important type of magnetized low-pressure plasma discharge, the pulsed magnetron.In industry, these plasma sources are operated typically in reactive mode where a cathode is sputtered in the presence of both chemically reactive and noble gases typically with the power modulated in the mid-frequency (5–350 kHz) range. In this review, we concentrate mostly, however, on physics-based studies carried out on magnetron systems operated in argon. This simplifies the physical–chemical processes occurring and makes interpretation of the observations somewhat easier.Since their first recorded use in 1993 there have been more than 300 peer-reviewed paper publications concerned with pulsed magnetrons, dealing wholly or in part with fundamental observations and basic studies. The fundamentals of these plasmas and the relationship between the plasma parameters and thin film quality regularly have whole sessions at international conferences devoted to them; however, since many different types of magnetron geometries have been used worldwide with different operating parameters the important results are often difficult to tease out. For example, we find the detailed observations of the plasma parameter (particle density and temperature) evolution from experiment to experiment are at best difficult to compare and at worst contradictory.We review in turn five major areas of studies which are addressed in the literature and try to draw out the major results. These areas are: fast electron generation, bulk plasma heating, short and long-term plasma parameter rise and decay rates, plasma potential modulation and transient phenomena. The influence of these phenomena on the ion energy and ion energy flux at the substrate is discussed. This review, although not exhaustive, will serve as a useful guide for more in-depth investigations using the referenced literature and also hopefully as an inspiration for future studies.

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Process Diagnostics

Bradley

Welzel

2008

Springer Series in Materials Science

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Two-Dimensional Double Probe Study of the Temporal Evolution of the Charge Carrier Density in a Pulsed Magnetron

Cited by 6 publications

References 29 publications

Spatial and temporal development of the plasma potential in differently configured pulsed magnetron discharges

Spatial and temporal development of the plasma potential in differently configured pulsed magnetron discharges

Physics and phenomena in pulsed magnetrons: an overview

Process Diagnostics

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