Electromagnetic (EM) and Electric Asymmetry (EA) Effects in Dual Frequency Collisional Nitrogen Capacitive Discharges
POSTER
Abstract
Intermediate pressure capacitive discharges containing nitrogen gas, are
common in the thin film processing industries, and are typically operated in
the α-mode, but at powers close to the transition to the γ-mode,
characterized by the collapse of the sheath width and the clamping of the
sheath voltage at the breakdown voltage. For a given voltage, higher frequency
drives can maintain discharges at higher densities, but at the cost of
enhancing electromagnetic (EM) effects leading to plasma non-uniformity.
A possible solution is to operate the discharge with both the fundamental
drive to maintain the sheath width and a supplemental second harmonic drive to
enhance the density. Even in symmetrically-driven discharges, this
configuration can lead to electric asymmetry (EA) effects. We study these EA
effects by conducting one-dimensional (1D) particle-in-cell (PIC) simulations
of a dual frequency (13.56/27.12 MHz) symmetrically-driven 1.6 Torr nitrogen
discharge at various relative phases between the frequencies. We then develop
a dual frequency two-dimensional (2D) EM fluid sheath model for this discharge,
taking the EA effects into account, in order to study the EM effects of this
configuration.
common in the thin film processing industries, and are typically operated in
the α-mode, but at powers close to the transition to the γ-mode,
characterized by the collapse of the sheath width and the clamping of the
sheath voltage at the breakdown voltage. For a given voltage, higher frequency
drives can maintain discharges at higher densities, but at the cost of
enhancing electromagnetic (EM) effects leading to plasma non-uniformity.
A possible solution is to operate the discharge with both the fundamental
drive to maintain the sheath width and a supplemental second harmonic drive to
enhance the density. Even in symmetrically-driven discharges, this
configuration can lead to electric asymmetry (EA) effects. We study these EA
effects by conducting one-dimensional (1D) particle-in-cell (PIC) simulations
of a dual frequency (13.56/27.12 MHz) symmetrically-driven 1.6 Torr nitrogen
discharge at various relative phases between the frequencies. We then develop
a dual frequency two-dimensional (2D) EM fluid sheath model for this discharge,
taking the EA effects into account, in order to study the EM effects of this
configuration.
*This work is supported by a gift from Applied Materials Corp., AKT Display Group
Publication: We plan to publish this research once completed, but have not yet decided on the journal for publication
Presenters
-
Emi Kawamura
- University of California, Berkeley