Speaker
Svetlana Radovanov
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/I2.306.pdf
Extraction of Positive and Negative Ion Beams from Large Area Plasma
Sources
S. Radovanov1, A. Samolov1
1
Applied Materials, SPG, Gloucester, Massachusetts, USA
Energetic ion beams, extracted from large area radio frequency (RF) plasma sources, are
used for material modifications in the leading-edge technologies.
One example is the large area inductively coupled plasma (ICP) source used in flat panel
plasma vapour deposition (PVD) system, where an ion beam sputter etch is used to reduce
the contact resistance prior to depositing an oxide layer.
While implantation and deposition are mainly utilizing positive ions, etching and beam
neutralization can be done with negative ions, as well. Negative ions are extracted from the
afterglow phase of pulsed plasmas, while positive ions can be extracted from both the DC
and pulsed plasmas. In the case of pulsed plasma, extraction electrodes and a treated surface
are biased synchronously with the discharge modulation for positive/negative ion transport to
the target. The energy of extracted ions closely follows the amplitude of the applied bias
voltage and it ranges from few hundreds of electron volt to 20 keV. The peak beam current
density can reach 100 A/m2.
In this paper we review the production and extraction of positive and negative ions from the
DC and pulsed RF plasma sources.
The experimental verification of the ion angular distribution (IAD), ion current and ion
composition is reported. The extraction physics requires correlating the positive and negative
ion and electron densities near the extraction opening with the extracted currents. This
system is modelled using the CRTRS, 2D/3D code, a plasma fluid code that self-consistently
solves for ICP power deposition, electrostatic potential and plasma dynamics in the
drift-diffusion approximation.
The focus is on the transport of low energy beams. A new perspective on the possible
production of angled ion beams on surfaces is discussed.
The authors acknowledge Dan Distaso and Joseph Dzengeleski for their expertise in control
systems and Shahid Rauf for the development of CRTRS code.
