Extraction of a nearly monoenergetic ion beam using a pulsed plasma

Abstract

A nearly monoenergetic ion beam was extracted from a capacitively coupled pulsed Ar plasma. The electron temperature decayed rapidly in the afterglow, resulting in uniform plasma potential, and minimal energy spread for ions extracted in the afterglow. Ion energy was controlled by a dc bias on a ring electrode surrounding the plasma. Langmuir probe measurements indicated that this bias simply raised the plasma potential without heating the electrons in the afterglow. A rejection grid downstream of the plasma allowed ions to pass only during a selected time window in the afterglow. The energy spread was 3.4 eV full width at half maximum for a peak ion beam energy of 102.0 eV. This energy spread is about an order of magnitude narrower than the beam extracted from the continuous plasma.

Nickel atom and ion densities in an inductively coupled plasma with an internal coil

“…One such process that we have recently reported, nanopantography, is a method for creating nanosize patterns in a massively parallel fashion over large areas. 4 A monoenergetic, collimated ion beam is extracted from a plasma 5 and encounters a substrate in a downstream high vacuum chamber. Ion beamlets are focused on the substrate by electrostatic lenses built on the substrate using standard photolithography and etching.…”

Modeling and Simulation of Fast Neutral Beam Sources for Materials Processing

“… Nearly monoenergetic distribution of extracted ions for different DC bias potentials (30, 50, 70, and 100 V) applied in the afterglow (RF power off, top) 48. Experimental data from ref 56. for the same conditions as in the simulation (bottom, FWHM = full width at half maximum).…”

“…This may be accomplished with the system shown in Figure 3. The strategy used to obtain a nearly monoenergetic ion beam was described in refs 55, 56. The RF plasma power was pulsed ON (active glow) and OFF (afterglow) with a certain frequency and duty ratio.…”

“…The small tail on the left of the IEDs is due to infrequent charge exchange collisions of ions with neutrals. The corresponding experimental data56 are shown in Figure 12 (bottom). Very good agreement with the simulation results is obtained, except that the width of the experimental IEDs is a bit larger than predicted, probably due to the finite resolution of the gridded ion energy analyzer used for measurements.…”

Mechanisms and selectivity for etching of HfO2 and Si in BCl3 plasmas

“…24 All the ion energy distribution measurements were carried out with the stage grounded. A Langmuir probe ͑Scientific Systems Smart Probe͒ was used to measure ion and electron densities, electron temperatures, and plasma and floating potentials.…”