60th Gaseous Electronics Conference
Volume 52, Number 9
Tuesday–Friday, October 2–5, 2007;
Arlington, Virginia
Session ET2: Electronegative Plasmas
4:00 PM–6:00 PM,
Tuesday, October 2, 2007
Doubletree Crystal City
Room: Crystal Ballroom B
Chair: Matt Goeckner, University of Texas at Dallas
Abstract ID: BAPS.2007.GEC.ET2.1
Abstract: ET2.00001 : Plasma-Based Low Energy Ion Implantation*
4:00 PM–4:30 PM
Preview Abstract
Abstract
Author:
Ludovic Godet
(Varian Semiconductor Equipment Associates)
After intense research and development of plasma doping systems, successful
application of pulsed glow discharge in low energy ion implantation has been
demonstrated. This approach offers great potential for both economic
benefit, as a much higher throughput process than traditional beam line
implantation, as well as enabling new fabrication options for advanced CMOS
or non-planar implant. Understanding the discharge physics - collisions, ion
energy distributions, plasma composition, secondary electron emission in the
sheath of the dc pulsed plasma is indispensable for controlling the low
energy ion implantation process. In this paper, ion energy distribution is
directly measured from the high voltage sheath in a pulsed dc glow discharge
using BF3 or BF3 mixed with inert gases as a gas feedstock. The impact of
the ratio of BF3 mixed with inert gases on the ion energy distribution of
the different ions and plasma parameters in the bulk and in the sheath is
studied. The effects of elastic and inelastic collisions in the sheath on
the ion energy distributions were experimentally and theoretically
determined. It was found in several experiments that molecular ion such as
BF2+ dominates the BF3 glow discharge. A possibility of negative ion
formation is discussed with the recent experimental results taken into
account. The analysis of the ion energy distribution and plasma parameters
enabled a better understanding of the key parameters that control the
nature, the concentration and the depth distribution of the implanted
species. Based on the ion energy distributions measured with the mass
spectrometer, the dopant depth profile is predicted and the plasma
parameters are optimized in order to obtain shallow dopant depth
distribution in the silicon after plasma doping implantation. This review of
pulsed plasma-based implantation for semiconductor applications will focus
on plasma diagnostics results thus far and the prospects for low energy
implant applications.
*Acknowledge Dr Svetlana Radovanov for participating in this research
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2007.GEC.ET2.1