Ion-acoustic solitary waves in a high power pulsed magnetron sputtering discharge

Gylfason, Kristinn B.; Alami, Jones; Helmersson, Ulf; Guðmundsson, Jón Tómas

doi:10.1088/0022-3727/38/18/015

Cited by 37 publications

(26 citation statements)

References 30 publications

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“…94,95,135,[140][141][142][143][144][145][146][147][148] Measurements of the temporal and spatial behavior of the plasma parameters indicate a peak electron density of the order of 10 18 -10 19 m À3 , 94,95,140 which during the ignition and growth phase expands from the target as an ion acoustic wave, with a fixed velocity that depends on the gas pressure. 149 This is roughly 2 orders of magnitude higher density than commonly observed in the substrate vicinity for a conventional dcMS discharge. Figure 8 shows the spatial distribution of the electron density in front of a titanium target for various times after initiating the pulse for a gas pressure of 2.7 Pa (after Bohlmark et al 140,150 ).…”

Section: A Electron Energy Electron Density and Electrical Potentialsmentioning

confidence: 82%

High power impulse magnetron sputtering discharge

Guðmundsson¹,

Brenning²,

Lundin³

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

637

446

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The high power impulse magnetron sputtering (HiPIMS) discharge is a recent addition to plasma based sputtering technology. In HiPIMS, high power is applied to the magnetron target in unipolar pulses at low duty cycle and low repetition frequency while keeping the average power about 2 orders of magnitude lower than the peak power. This results in a high plasma density, and high ionization fraction of the sputtered vapor, which allows better control of the film growth by controlling the energy and direction of the deposition species. This is a significant advantage over conventional dc magnetron sputtering where the sputtered vapor consists mainly of neutral species. The HiPIMS discharge is now an established ionized physical vapor deposition technique, which is easily scalable and has been successfully introduced into various industrial applications. The authors give an overview of the development of the HiPIMS discharge, and the underlying mechanisms that dictate the discharge properties. First, an introduction to the magnetron sputtering discharge and its various configurations and modifications is given. Then the development and properties of the high power pulsed power supply are discussed, followed by an overview of the measured plasma parameters in the HiPIMS discharge, the electron energy and density, the ion energy, ion flux and plasma composition, and a discussion on the deposition rate. Finally, some of the models that have been developed to gain understanding of the discharge processes are reviewed, including the phenomenological material pathway model, and the ionization region model.

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Section: A Electron Energy Electron Density and Electrical Potentialsmentioning

confidence: 82%

High power impulse magnetron sputtering discharge

Guðmundsson¹,

Brenning²,

Lundin³

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

637

446

View full text Add to dashboard Cite

show abstract

“…The magnetic field arches over the target at a radius of 6 22 mm from the center; this is the location of the racetrack, indicated by the large arrows. also detected by probe measurements [25][26][27][28][29] ). Hála and coworkers 30,31 used optical emission spectroscopy and time resolved imaging (5 ls resolution with image averaging), also indicating the existing of a wave traveling away from the target.…”

Section: Fig 2 (Color Online)mentioning

confidence: 87%

Drifting localization of ionization runaway: Unraveling the nature of anomalous transport in high power impulse magnetron sputtering

Anders

Rauch

2012

Journal of Applied Physics

157

192

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“…Pressure and plasma density waves have been observed before in HIPIMS systems [46]. In some cases one sees only one pulse propagating, resembling a solitary wave [47], which is most likely caused by the switch-on of the "sputter wind".…”

Section: Gas Rarefaction and Sputter Windmentioning

confidence: 89%

Discharge physics of high power impulse magnetron sputtering

Anders

2011

Surface and Coatings Technology

246

134

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High power impulse magnetron sputtering (HIPIMS) is pulsed sputtering where the peak power exceeds the time-averaged power by typically two orders of magnitude. The peak power density, averaged over the target area, can reach or exceed 10 7 W/m 2 , leading to plasma conditions that make ionization of the sputtered atoms very likely. A brief review of HIPIMS operation is given in a tutorial manner, illustrated by some original data related to the selfsputtering of niobium in argon and krypton. Emphasis is put on the current-voltage-time relationships near the threshold of self-sputtering runaway. The great variety of current pulse shapes delivers clues on the very strong gas rarefaction, self-sputtering runaway conditions, and the stopping of runaway due to the evolution of atom ionization and ion return probabilities as the gas plasma is replaced by metal plasma. The discussions are completed by considering instabilities and the special case of "gasless" self-sputtering. IntroductionDerived from a Plenary Talk at the 2010 Plasma Engineering Conference, this work is limited to a brief recap of sputtering basics followed by considerations of how the magnetron operates under high power pulsed conditions. The emphasis will be on the ionization of sputtered atoms followed by self-sputtering, which may or may not amplify to result in selfsputtering "runaway". The runaway phenomenon will be illustrated by new data related to its onset and the establishment of sustained, steady-state self-sputtering. For simplicity and transparency, and given the finite space, the considerations are mostly phenomenological and limited to non-reactive sputtering using pure argon or krypton.High power impulse magnetron sputtering (HIPIMS) is a relatively young physical vapor deposition (PVD) technology that combines magnetron sputtering with pulsed power technology [1][2][3]. The objective is to achieve ionization of the sputtered atoms in order to have ions available for substrate etching (pre-treatment) [4] and/or for assistance to the film growth process, leading to well-adherent coatings of desirable microstructure and properties [5].In contrast to conventional mid-frequency pulsed sputtering, the power densities during pulse on-time are much higher in HIPIMS. To clearly define the scope, two definitions of HIPIMS are offered here. First, a technical definition could be "HIPIMS is pulsed sputtering where the peak power exceeds the time-averaged power by typically two orders of magnitude." This definition implies that long pauses exist between pulses of very high amplitude, hence the word "impulse" is justified in the terminology. The peak power density, averaged over the target area, often exceeds 10

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Ion-acoustic solitary waves in a high power pulsed magnetron sputtering discharge

Cited by 37 publications

References 30 publications

High power impulse magnetron sputtering discharge

High power impulse magnetron sputtering discharge

Drifting localization of ionization runaway: Unraveling the nature of anomalous transport in high power impulse magnetron sputtering

Discharge physics of high power impulse magnetron sputtering

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