Secondary electrons in dual-frequency capacitive radio frequency discharges

J. Schulze, Z. Donkó, E. Schüngel, U. Czarnetzki

Research output: Contribution to journalArticle

62 Citations (Scopus)

Abstract

Two fundamentally different types of dual-frequency (DF) capacitively coupled radio frequency discharges can be used for plasma processing applications to realize separate control of the ion mean energy, 〈E i〉, and the ion flux, Γi, at the substrate surface: (i) classical discharges operated at substantially different frequencies, where the low- and high-frequency voltage amplitudes, lf and hf, are used to control 〈Ei〉 and Γi, respectively; (ii) electrically asymmetric (EA) discharges operated at a fundamental frequency and its second harmonic with fixed, but adjustable phase shift between the driving frequencies, . In EA discharges the voltage amplitudes are used to control Γi and is used to control 〈Ei〉. Here, we report our systematic simulation studies of the effect of secondary electrons on the ionization dynamics and the quality of this separate control in both discharge types in argon at different gas pressures. We focus on the effect of the control parameter for 〈E i〉 on Γi for different secondary yields, γ. We find a dramatic effect of tuning lf in classical DF discharges, which is caused by a transition from α- to γ-mode induced by changing lf. In EA discharges we find that no such mode transition is induced by changing within the parameter range studied here and, consequently, Γi remains nearly constant as a function of . Thus, despite some limitations at high values of γ the quality of the separate control of ion energy and flux is generally better in EA discharges compared with classical DF discharges.

Original languageEnglish
Article number045007
JournalPlasma Sources Science and Technology
Volume20
Issue number4
DOIs
Publication statusPublished - Aug 2011

Fingerprint

radio frequency discharge
electrons
ions
electric potential
gas pressure
phase shift
tuning
argon
low frequencies
harmonics
ionization
energy

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Secondary electrons in dual-frequency capacitive radio frequency discharges. / Schulze, J.; Donkó, Z.; Schüngel, E.; Czarnetzki, U.

In: Plasma Sources Science and Technology, Vol. 20, No. 4, 045007, 08.2011.

Research output: Contribution to journalArticle

@article{5f91d670a2724dc89afd6ec9486dba45,
title = "Secondary electrons in dual-frequency capacitive radio frequency discharges",
abstract = "Two fundamentally different types of dual-frequency (DF) capacitively coupled radio frequency discharges can be used for plasma processing applications to realize separate control of the ion mean energy, 〈E i〉, and the ion flux, Γi, at the substrate surface: (i) classical discharges operated at substantially different frequencies, where the low- and high-frequency voltage amplitudes, lf and hf, are used to control 〈Ei〉 and Γi, respectively; (ii) electrically asymmetric (EA) discharges operated at a fundamental frequency and its second harmonic with fixed, but adjustable phase shift between the driving frequencies, . In EA discharges the voltage amplitudes are used to control Γi and is used to control 〈Ei〉. Here, we report our systematic simulation studies of the effect of secondary electrons on the ionization dynamics and the quality of this separate control in both discharge types in argon at different gas pressures. We focus on the effect of the control parameter for 〈E i〉 on Γi for different secondary yields, γ. We find a dramatic effect of tuning lf in classical DF discharges, which is caused by a transition from α- to γ-mode induced by changing lf. In EA discharges we find that no such mode transition is induced by changing within the parameter range studied here and, consequently, Γi remains nearly constant as a function of . Thus, despite some limitations at high values of γ the quality of the separate control of ion energy and flux is generally better in EA discharges compared with classical DF discharges.",
author = "J. Schulze and Z. Donk{\'o} and E. Sch{\"u}ngel and U. Czarnetzki",
year = "2011",
month = "8",
doi = "10.1088/0963-0252/20/4/045007",
language = "English",
volume = "20",
journal = "Plasma Sources Science and Technology",
issn = "0963-0252",
publisher = "IOP Publishing Ltd.",
number = "4",

}

TY - JOUR

T1 - Secondary electrons in dual-frequency capacitive radio frequency discharges

AU - Schulze, J.

AU - Donkó, Z.

AU - Schüngel, E.

AU - Czarnetzki, U.

PY - 2011/8

Y1 - 2011/8

N2 - Two fundamentally different types of dual-frequency (DF) capacitively coupled radio frequency discharges can be used for plasma processing applications to realize separate control of the ion mean energy, 〈E i〉, and the ion flux, Γi, at the substrate surface: (i) classical discharges operated at substantially different frequencies, where the low- and high-frequency voltage amplitudes, lf and hf, are used to control 〈Ei〉 and Γi, respectively; (ii) electrically asymmetric (EA) discharges operated at a fundamental frequency and its second harmonic with fixed, but adjustable phase shift between the driving frequencies, . In EA discharges the voltage amplitudes are used to control Γi and is used to control 〈Ei〉. Here, we report our systematic simulation studies of the effect of secondary electrons on the ionization dynamics and the quality of this separate control in both discharge types in argon at different gas pressures. We focus on the effect of the control parameter for 〈E i〉 on Γi for different secondary yields, γ. We find a dramatic effect of tuning lf in classical DF discharges, which is caused by a transition from α- to γ-mode induced by changing lf. In EA discharges we find that no such mode transition is induced by changing within the parameter range studied here and, consequently, Γi remains nearly constant as a function of . Thus, despite some limitations at high values of γ the quality of the separate control of ion energy and flux is generally better in EA discharges compared with classical DF discharges.

AB - Two fundamentally different types of dual-frequency (DF) capacitively coupled radio frequency discharges can be used for plasma processing applications to realize separate control of the ion mean energy, 〈E i〉, and the ion flux, Γi, at the substrate surface: (i) classical discharges operated at substantially different frequencies, where the low- and high-frequency voltage amplitudes, lf and hf, are used to control 〈Ei〉 and Γi, respectively; (ii) electrically asymmetric (EA) discharges operated at a fundamental frequency and its second harmonic with fixed, but adjustable phase shift between the driving frequencies, . In EA discharges the voltage amplitudes are used to control Γi and is used to control 〈Ei〉. Here, we report our systematic simulation studies of the effect of secondary electrons on the ionization dynamics and the quality of this separate control in both discharge types in argon at different gas pressures. We focus on the effect of the control parameter for 〈E i〉 on Γi for different secondary yields, γ. We find a dramatic effect of tuning lf in classical DF discharges, which is caused by a transition from α- to γ-mode induced by changing lf. In EA discharges we find that no such mode transition is induced by changing within the parameter range studied here and, consequently, Γi remains nearly constant as a function of . Thus, despite some limitations at high values of γ the quality of the separate control of ion energy and flux is generally better in EA discharges compared with classical DF discharges.

UR - http://www.scopus.com/inward/record.url?scp=80051641825&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=80051641825&partnerID=8YFLogxK

U2 - 10.1088/0963-0252/20/4/045007

DO - 10.1088/0963-0252/20/4/045007

M3 - Article

VL - 20

JO - Plasma Sources Science and Technology

JF - Plasma Sources Science and Technology

SN - 0963-0252

IS - 4

M1 - 045007

ER -