{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/69418"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/69418","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Enhancement of the Negative Ion Flux to Surfaces From Radio-Frequency Processing Discharges","abstract":"The relative flux of negative ions from rf discharges through CF$\\sb4$ and F$\\sb2$-He has been studied using mass spectrometry. The negative ion flux impinging on a surface in contact with a glow discharge is usually quite small because of the sheaths formed to contain the more mobile electrons. In the afterglow however, these sheaths decay on the time scale of the electron density loss rate while negative ions can remain in the discharge region significantly longer. As a consequence, the negative ion flux to a surface in contact with the glow discharge can rise by a very large amount in the afterglow when the sheaths have diminished. It is shown here that the flux of the negative ions can be enhanced by factors of 50 to greater than 1000 by SQuare Wave amplitude Modulating (SQWM) the rf discharge. This enhancement depends upon the dc self-bias voltage and the modulation frequency as well as the particular negative ion. Data are presented for both CF$\\sb4$ and F$\\sb2$-helium discharges, along with the correlation to simple models.","abstract_html":"The relative flux of negative ions from rf discharges through CF$\\sb4$ and F$\\sb2$-He has been studied using mass spectrometry. The negative ion flux impinging on a surface in contact with a glow discharge is usually quite small because of the sheaths formed to contain the more mobile electrons. In the afterglow however, these sheaths decay on the time scale of the electron density loss rate while negative ions can remain in the discharge region significantly longer. As a consequence, the negative ion flux to a surface in contact with the glow discharge can rise by a very large amount in the afterglow when the sheaths have diminished. It is shown here that the flux of the negative ions can be enhanced by factors of 50 to greater than 1000 by SQuare Wave amplitude Modulating (SQWM) the rf discharge. This enhancement depends upon the dc self-bias voltage and the modulation frequency as well as the particular negative ion. Data are presented for both CF$\\sb4$ and F$\\sb2$-helium discharges, along with the correlation to simple models.","abstract_has_math":true,"creators":["Overzet, Lawrence John"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Electrical Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-15T19:05:42Z","date_published":"2014-12-15T19:05:42Z","updated_at":"2026-07-22T22:26:00Z","subjects":["Engineering, Electronics and Electrical","Physics, Electricity and Magnetism"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8908796"],"render_values":[{"text":"(UMI)AAI8908796","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/69418","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Overzet, Lawrence John"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-15T19:05:42Z","10000-01-01","1988"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Electronics and Electrical","Physics, Electricity and Magnetism"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/69418","(UMI)AAI8908796"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The relative flux of negative ions from rf discharges through CF$\\sb4$ and F$\\sb2$-He has been studied using mass spectrometry. The negative ion flux impinging on a surface in contact with a glow discharge is usually quite small because of the sheaths formed to contain the more mobile electrons. In the afterglow however, these sheaths decay on the time scale of the electron density loss rate while negative ions can remain in the discharge region significantly longer. As a consequence, the negative ion flux to a surface in contact with the glow discharge can rise by a very large amount in the afterglow when the sheaths have diminished. It is shown here that the flux of the negative ions can be enhanced by factors of 50 to greater than 1000 by SQuare Wave amplitude Modulating (SQWM) the rf discharge. This enhancement depends upon the dc self-bias voltage and the modulation frequency as well as the particular negative ion. Data are presented for both CF$\\sb4$ and F$\\sb2$-helium discharges, along with the correlation to simple models.","Made available in DSpace on 2014-12-15T19:05:42Z (GMT). No. of bitstreams: 1 8908796.pdf: 2193371 bytes, checksum: 15445ce4bf9d97ec2dbf46031ee0a43c (MD5) Previous issue date: 1988","Embargo set by: Seth Robbins for item 69584 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","60 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988."]},{"key":"dc:title","label":"Title","values":["Enhancement of the Negative Ion Flux to Surfaces From Radio-Frequency Processing Discharges"]}]}],"canonical_facts":{"dc:creator":["Overzet, Lawrence John"],"dc:date":["2014-12-15T19:05:42Z","10000-01-01","1988"],"dc:description":["The relative flux of negative ions from rf discharges through CF$\\sb4$ and F$\\sb2$-He has been studied using mass spectrometry. The negative ion flux impinging on a surface in contact with a glow discharge is usually quite small because of the sheaths formed to contain the more mobile electrons. In the afterglow however, these sheaths decay on the time scale of the electron density loss rate while negative ions can remain in the discharge region significantly longer. As a consequence, the negative ion flux to a surface in contact with the glow discharge can rise by a very large amount in the afterglow when the sheaths have diminished. It is shown here that the flux of the negative ions can be enhanced by factors of 50 to greater than 1000 by SQuare Wave amplitude Modulating (SQWM) the rf discharge. This enhancement depends upon the dc self-bias voltage and the modulation frequency as well as the particular negative ion. Data are presented for both CF$\\sb4$ and F$\\sb2$-helium discharges, along with the correlation to simple models.","Made available in DSpace on 2014-12-15T19:05:42Z (GMT). No. of bitstreams: 1 8908796.pdf: 2193371 bytes, checksum: 15445ce4bf9d97ec2dbf46031ee0a43c (MD5) Previous issue date: 1988","Embargo set by: Seth Robbins for item 69584 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","60 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1988."],"dc:identifier":["http://hdl.handle.net/2142/69418","(UMI)AAI8908796"],"dc:subject":["Engineering, Electronics and Electrical","Physics, Electricity and Magnetism"],"dc:title":["Enhancement of the Negative Ion Flux to Surfaces From Radio-Frequency Processing Discharges"],"dc:type":["text"],"thesis:degree_discipline":["Electrical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:00Z"}