AVS 58th Annual International Symposium and Exhibition
    Plasma Science and Technology Division Thursday Sessions
       Session PS-ThP

Paper PS-ThP18
Synchronous Pulsed Inductively Coupled Plasma Source for Controllable Charged Process

Thursday, November 3, 2011, 6:00 pm, Room East Exhibit Hall

Session: Plasma Science and Technology Poster Session
Presenter: KyungSeok Min, Sungkyunkwan University, Republic of Korea
Authors: K.S. Min, Sungkyunkwan University, Republic of Korea
J.S. Oh, Sungkyunkwan University, Republic of Korea
C.K. Kim, Sungkyunkwan University, Republic of Korea
G.Y. Yeom, Sungkyunkwan University, Republic of Korea
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A high-density ion source derived from an inductively coupled plasma is a useful tool in the fabrication of devices. A disadvantage of the technique is that charge-induced damage can cause irreversible changes in the device properties. In order to avoid or to compensate for the non-uniform accumulation of positive and negative charges near the treated surface, a number of low-damage processes have been proposed. The most promising of these processes uses high-energy 10–1000 eV beams of fast atoms and radicals for surface treatment.

This letter reports on a different method of negative beam formation that has potential application to neutral beam etching. In particular, we obtain a flux of fast neutral atoms with narrow energy and angular distribution from an initially negative ion beam which is extracted from the discharge volume with energy of 10 – 500 eV and then neutralized. By increasing the pulse frequency of the antenna voltage to 20 kHz and applying a synchronized bipolar potential to the accelerating electrodes, it is possible to produce a high-density negative ion beam whose energy level is determined by the amplitude of the extraction potential. During the discharge, a positive potential is applied to the extraction electrode and a negative potential to the focusing electrode. In the afterglow period, these potentials are switched, allowing high-energy negative ions to escape the source. The lower and upper limits of the bipolar extraction potential on the two electrodes can be varied independently, so that the ratio of negative ions to positive ions in the resulting beam can be adjusted from 0% to 100%.