Ion-induced electron emission from clean metals

Baragiola, R. A.; Alonso, E.V.; Ferrón, J.; Oliva-Florio, A.

doi:10.1016/0039-6028(79)90341-8

Cited by 265 publications

(106 citation statements)

References 39 publications

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“…The secondary electron emission yield (γSE) is influenced by the ionization energy of the working gas (Ip) and the work function (φ) of the target surface 33 . Upon introduction of N2 to the Si-discharge, the effective Ip of the process gas does not change considerably owing to similar ionization energies of N2 (IP(N2) = 15.6 eV) and N (IP(N) = 14.53 eV) and Ar (IP(Ar) = 15.75 eV).…”

Section: Process Characteristics and Plasma Characterizationmentioning

confidence: 99%

SiN_x Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

Schmidt

Hänninen

Goyenola

et al. 2016

ACS Appl. Mater. Interfaces

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Reactive high power impulse magnetron sputtering (rHiPIMS) was used to deposit silicon nitride (SiNx) coatings for bio-medical applications. The SiNx growth and plasma characterization were conducted in an industrial coater, using Si targets and N2 as reactive gas. The effects of different N2-toAr flow ratios between 0 and 0.3, pulse frequencies, target power settings and substrate temperatures on the discharge and the N content of SiNx coatings were investigated. Plasma ion mass spectrometry shows high amounts of ionized isotopes during the initial part of the pulse for discharges with low N2-to-Ar flow ratios of < 0.16, while signals from ionized molecules rise with the N2-to-Ar flow ratio at the pulse end and during pulse-off times. Langmuir probe measurements show electron temperatures between 2 -3 eV for non-reactive discharges and 5.0 to 6.6 eV for discharges in transition mode. The SiNx coatings were characterized with respect to their composition, chemical bond structure, density and mechanical properties by X-ray photoelectron spectroscopy, X-ray reflectivity, X-ray diffraction, and nanoindentation, respectively. The SiNx deposition processes and coating properties are mainly influenced by the N2-to-Ar flow ratio and thus by the N content in the SiNx films and to a lower extent by the HiPIMS frequencies and power settings as well as substrate temperatures. Increasing N2-to-Ar flow ratios lead to decreasing growth rates, while the N contents, coating densities, residual stresses and the hardnesses increase. These experimental findings were corroborated by density functional theory calculations of precursor species present during rHiPIMS.

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Section: Process Characteristics and Plasma Characterizationmentioning

confidence: 99%

SiN_x Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

Schmidt

Hänninen

Goyenola

et al. 2016

ACS Appl. Mater. Interfaces

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“…emission associated with the ionization potential of the arriving ion [52]. Experimental data of the secondary emission yields for various ions satisfy the fit [54]   0.032 0.78 2…”

Section: The Evolution Of the Secondary Electron Emission And Ionizatmentioning

confidence: 99%

Discharge physics of high power impulse magnetron sputtering

Anders

2011

Surface and Coatings Technology

241

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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“…It has been known for some years that the issue of very low net γ could be further aggravated when singly charged metal ions replace the noble gas ions during each HiPIMS 3 pulse. 9 The yield for singly charged metal ions is zero based on Baragiola's empirical yield formula 10 …”

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confidence: 99%

Localized heating of electrons in ionization zones: Going beyond the Penning-Thornton paradigm in magnetron sputtering

Anders

2014

Applied Physics Letters

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The fundamental question of how energy is supplied to a magnetron discharge is commonly answered by the Penning-Thornton paradigm invoking secondary electrons. Recently, Huo and coworkers (Plasma Sources Sci. Technol. 22, 045005 (2013)) used a global discharge model to show that electron heating in the electric field of the magnetic presheath is dominant over heating by secondary electrons. In this contribution, this concept is applied locally taking into account the electric potential structure of ionization zones. Images of ionization zones can and should be interpreted as diagrams of the localization of high electric potential and related electron energy.

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Ion-induced electron emission from clean metals

Cited by 265 publications

References 39 publications

SiN_x Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

SiN_x Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

Discharge physics of high power impulse magnetron sputtering

Localized heating of electrons in ionization zones: Going beyond the Penning-Thornton paradigm in magnetron sputtering

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Ion-induced electron emission from clean metals

Cited by 265 publications

References 39 publications

SiNx Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

SiNx Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

Discharge physics of high power impulse magnetron sputtering

Localized heating of electrons in ionization zones: Going beyond the Penning-Thornton paradigm in magnetron sputtering

Contact Info

Product

Resources

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SiN_x Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

SiN_x Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content