{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/34801"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/34801","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Polymer-Supported Bridges for Multi-Finger AlGaN/GaN Heterojunction Field Effect Transistors (HFETs)","abstract":"Current AlGaN/GaN Heterojunction Field Effect Transistors (HFETs) make use of multiple sources, drains, and gates in parallel to maximize transconductance and effective gain while minimizing the current density through each channel. To connect the sources to a common ground, current practice prescribes the fabrication of air bridges above the gates and drains. This practice has the advantage of a low dielectric constant and low parasitic capacitance, but it is at the expense of manufacturability and robust device operation. In the study described below, the air bridges in AlGaN/GaN HFETs were replaced by a polymer supported metallization bridge with the intention of improving ease of fabrication and reliability. The DC, high frequency, and power performance for several polymer step heights were investigated. The resultant structures were functional and robust; however, their electrical performance was degraded due to high source resistance. The cause of the high source resistance was found to be thinning of the metallization at the polymer step. The effect was more pronounced for higher step heights.","abstract_html":"Current AlGaN/GaN Heterojunction Field Effect Transistors (HFETs) make use of multiple sources, drains, and gates in parallel to maximize transconductance and effective gain while minimizing the current density through each channel. To connect the sources to a common ground, current practice prescribes the fabrication of air bridges above the gates and drains. This practice has the advantage of a low dielectric constant and low parasitic capacitance, but it is at the expense of manufacturability and robust device operation. In the study described below, the air bridges in AlGaN/GaN HFETs were replaced by a polymer supported metallization bridge with the intention of improving ease of fabrication and reliability. The DC, high frequency, and power performance for several polymer step heights were investigated. The resultant structures were functional and robust; however, their electrical performance was degraded due to high source resistance. The cause of the high source resistance was found to be thinning of the metallization at the polymer step. The effect was more pronounced for higher step heights.","abstract_has_math":false,"creators":["Willemann, Michael Howard"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Materials Science and Engineering","degree_department":"Materials Science and Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Guido, Louis J."],"committee_members":["Aning, Alexander O.","Lu, Guo-Quan"],"year":2007,"date_issued":"2007-08-17","date_published":"2007-08-17","updated_at":"2026-07-22T22:19:10Z","subjects":["Wide-bandgap semiconductor","High Electron Mobility Transistor","RF power electronics"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-08272007-085537"],"render_values":[{"text":"etd-08272007-085537","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/34801","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Guido, Louis J."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Aning, Alexander O.","Lu, Guo-Quan"]},{"key":"dc:contributor.department","label":"Department","values":["Materials Science and Engineering"]},{"key":"dc:creator","label":"Author","values":["Willemann, Michael Howard"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:44:19Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:44:19Z","2007-09-04"]},{"key":"dc:date.issued","label":"Date","values":["2007-08-17"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science and Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Wide-bandgap semiconductor","High Electron Mobility Transistor","RF power electronics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-08272007-085537"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/34801"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Current AlGaN/GaN Heterojunction Field Effect Transistors (HFETs) make use of multiple sources, drains, and gates in parallel to maximize transconductance and effective gain while minimizing the current density through each channel. To connect the sources to a common ground, current practice prescribes the fabrication of air bridges above the gates and drains. This practice has the advantage of a low dielectric constant and low parasitic capacitance, but it is at the expense of manufacturability and robust device operation. In the study described below, the air bridges in AlGaN/GaN HFETs were replaced by a polymer supported metallization bridge with the intention of improving ease of fabrication and reliability. The DC, high frequency, and power performance for several polymer step heights were investigated. The resultant structures were functional and robust; however, their electrical performance was degraded due to high source resistance. The cause of the high source resistance was found to be thinning of the metallization at the polymer step. The effect was more pronounced for higher step heights."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Polymer-Supported Bridges for Multi-Finger AlGaN/GaN Heterojunction Field Effect Transistors (HFETs)"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Guido, Louis J."],"dc:contributor.committeemember":["Aning, Alexander O.","Lu, Guo-Quan"],"dc:contributor.department":["Materials Science and Engineering"],"dc:creator":["Willemann, Michael Howard"],"dc:date.accessioned":["2014-03-14T20:44:19Z"],"dc:date.available":["2014-03-14T20:44:19Z","2007-09-04"],"dc:date.issued":["2007-08-17"],"dc:description.abstract":["Current AlGaN/GaN Heterojunction Field Effect Transistors (HFETs) make use of multiple sources, drains, and gates in parallel to maximize transconductance and effective gain while minimizing the current density through each channel. To connect the sources to a common ground, current practice prescribes the fabrication of air bridges above the gates and drains. This practice has the advantage of a low dielectric constant and low parasitic capacitance, but it is at the expense of manufacturability and robust device operation. In the study described below, the air bridges in AlGaN/GaN HFETs were replaced by a polymer supported metallization bridge with the intention of improving ease of fabrication and reliability. The DC, high frequency, and power performance for several polymer step heights were investigated. The resultant structures were functional and robust; however, their electrical performance was degraded due to high source resistance. The cause of the high source resistance was found to be thinning of the metallization at the polymer step. The effect was more pronounced for higher step heights."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-08272007-085537"],"dc:identifier.uri":["http://hdl.handle.net/10919/34801"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Wide-bandgap semiconductor","High Electron Mobility Transistor","RF power electronics"],"dc:title":["Polymer-Supported Bridges for Multi-Finger AlGaN/GaN Heterojunction Field Effect Transistors (HFETs)"],"dc:type":["Thesis"],"thesis:degree_discipline":["Materials Science and Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:10Z"}