{"id":{"repo_id":"vcu","oai_identifier":"oai:scholarscompass.vcu.edu:etd-2411"},"canonical_url":"https://search.dev.ndltd.org/etd/vcu/oai:scholarscompass.vcu.edu:etd-2411","repository":{"repo_id":"vcu","name":"Virginia Commonwealth University","base_url":"https://scholarscompass.vcu.edu/do/oai/"},"display":{"title":"CAFM Studies of Epitaxial Lateral Overgrowth GaN Films","abstract":"This thesis uses the techniques of atomic force microscopy (AFM) and conductiveAFM (CAFM) to study defect sites on GaN films. In particular, these defect sites demonstrate current leakage under reverse-bias conditions that are detrimental to device fabrication. Two growth techniques that were used to improve this leakage behavior for samples in this study included: epitaxial lateral overgrowth (ELO) and nano-ELO using a Si3N4 film. Both techniques decrease defects such as threading dislocations by controlling the nucleation and growth behavior of the GaN films. The EL0 technique uses a patterned dielectric film to laterally grow micron-wide regions (referred to as 'wings') that minimize dislocation defects. Our CAFM studies indicate that ELO films have no detectable leakage sites in these wing regions; however, between these regions the films have typical leakage site densities seen for standard films on the order of 107cm-3. The nano-ELO technique utilizes a porous Si3N4 film to reduce defects over the entire film, and CAFM data indicate nearly a factor of ten reduction in leakage site densities. The nano-ELO technique is therefore optimal for an overall improvement in film quality, whereas the ELO technique is suitable for device fabrication in patterned regions with optimized film quality.","abstract_html":"This thesis uses the techniques of atomic force microscopy (AFM) and conductiveAFM (CAFM) to study defect sites on GaN films. In particular, these defect sites demonstrate current leakage under reverse-bias conditions that are detrimental to device fabrication. Two growth techniques that were used to improve this leakage behavior for samples in this study included: epitaxial lateral overgrowth (ELO) and nano-ELO using a Si3N4 film. Both techniques decrease defects such as threading dislocations by controlling the nucleation and growth behavior of the GaN films. The EL0 technique uses a patterned dielectric film to laterally grow micron-wide regions (referred to as 'wings') that minimize dislocation defects. Our CAFM studies indicate that ELO films have no detectable leakage sites in these wing regions; however, between these regions the films have typical leakage site densities seen for standard films on the order of 107cm-3. The nano-ELO technique utilizes a porous Si3N4 film to reduce defects over the entire film, and CAFM data indicate nearly a factor of ten reduction in leakage site densities. The nano-ELO technique is therefore optimal for an overall improvement in film quality, whereas the ELO technique is suitable for device fabrication in patterned regions with optimized film quality.","abstract_has_math":false,"creators":["Kasliwal, Vishal P."],"institution":null,"degree_name":"Master of Science","degree_level":"Thesis","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Dr. Alison Baski"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2007,"date_issued":"2007-01-01T08:00:00Z","date_published":"2007-01-01T08:00:00Z","updated_at":"2026-07-24T05:55:14Z","subjects":["threading dislocation","semiconductor","growth behavior","leakage","defect site","gallium nitride","Physical Sciences and Mathematics","Physics"],"languages":[],"rights":["© The Author"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarscompass.vcu.edu/etd/1412"],"render_values":[{"text":"https://scholarscompass.vcu.edu/etd/1412","href":"https://scholarscompass.vcu.edu/etd/1412","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.25772/21FA-K271","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dr. Alison Baski"]},{"key":"dc:creator","label":"Author","values":["Kasliwal, Vishal P."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2014-07-09T07:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["threading dislocation","semiconductor","growth behavior","leakage","defect site","gallium nitride","Physical Sciences and Mathematics","Physics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["© The Author"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://doi.org/10.25772/21FA-K271","https://scholarscompass.vcu.edu/etd/1412"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This thesis uses the techniques of atomic force microscopy (AFM) and conductiveAFM (CAFM) to study defect sites on GaN films. In particular, these defect sites demonstrate current leakage under reverse-bias conditions that are detrimental to device fabrication. Two growth techniques that were used to improve this leakage behavior for samples in this study included: epitaxial lateral overgrowth (ELO) and nano-ELO using a Si3N4 film. Both techniques decrease defects such as threading dislocations by controlling the nucleation and growth behavior of the GaN films. The EL0 technique uses a patterned dielectric film to laterally grow micron-wide regions (referred to as 'wings') that minimize dislocation defects. Our CAFM studies indicate that ELO films have no detectable leakage sites in these wing regions; however, between these regions the films have typical leakage site densities seen for standard films on the order of 107cm-3. The nano-ELO technique utilizes a porous Si3N4 film to reduce defects over the entire film, and CAFM data indicate nearly a factor of ten reduction in leakage site densities. The nano-ELO technique is therefore optimal for an overall improvement in film quality, whereas the ELO technique is suitable for device fabrication in patterned regions with optimized film quality."]},{"key":"dc:title","label":"Title","values":["CAFM Studies of Epitaxial Lateral Overgrowth GaN Films"]}]}],"canonical_facts":{"dc:contributor":["Dr. Alison Baski"],"dc:creator":["Kasliwal, Vishal P."],"dc:date.available":["2014-07-09T07:00:00Z"],"dc:description.abstract":["This thesis uses the techniques of atomic force microscopy (AFM) and conductiveAFM (CAFM) to study defect sites on GaN films. In particular, these defect sites demonstrate current leakage under reverse-bias conditions that are detrimental to device fabrication. Two growth techniques that were used to improve this leakage behavior for samples in this study included: epitaxial lateral overgrowth (ELO) and nano-ELO using a Si3N4 film. Both techniques decrease defects such as threading dislocations by controlling the nucleation and growth behavior of the GaN films. The EL0 technique uses a patterned dielectric film to laterally grow micron-wide regions (referred to as 'wings') that minimize dislocation defects. Our CAFM studies indicate that ELO films have no detectable leakage sites in these wing regions; however, between these regions the films have typical leakage site densities seen for standard films on the order of 107cm-3. The nano-ELO technique utilizes a porous Si3N4 film to reduce defects over the entire film, and CAFM data indicate nearly a factor of ten reduction in leakage site densities. The nano-ELO technique is therefore optimal for an overall improvement in film quality, whereas the ELO technique is suitable for device fabrication in patterned regions with optimized film quality."],"dc:identifier":["https://doi.org/10.25772/21FA-K271","https://scholarscompass.vcu.edu/etd/1412"],"dc:rights":["© The Author"],"dc:subject":["threading dislocation","semiconductor","growth behavior","leakage","defect site","gallium nitride","Physical Sciences and Mathematics","Physics"],"dc:title":["CAFM Studies of Epitaxial Lateral Overgrowth GaN Films"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["Master of Science"]},"updated_at":"2026-07-24T05:55:14Z"}