{"id":{"repo_id":"wvu","oai_identifier":"oai:researchrepository.wvu.edu:etd-2354"},"canonical_url":"https://search.dev.ndltd.org/etd/wvu/oai:researchrepository.wvu.edu:etd-2354","repository":{"repo_id":"wvu","name":"West Virginia University","base_url":"https://researchrepository.wvu.edu/do/oai/"},"display":{"title":"Growth kinetics and doping of gallium nitride grown by rf-plasma assisted molecular beam epitaxy","abstract":"A reduced rate for growth of GaN by plasma-assisted molecular beam epitaxy often limits growth to temperatures less than 750°C, with the reduction significantly larger than thermal decomposition rates. Conditions producing a flux consisting predominantly of either atomic nitrogen or nitrogen metastables have been established using various rf-sources. Atomic nitrogen, possibly coupled with the presence of low energy ions, is associated with the premature decrease in growth rate. An active nitrogen flux consisting primarily of nitrogen metastables produces a temperature dependence more consistent with decomposition rates. Growth with molecular nitrogen metastables results in significantly improved electrical properties.;Magnesium incorporation was studied for both (0001), or Ga-polarity and (0001), or N-polarity, orientations for various growth conditions. A significant dependence on surface polarity of Mg incorporation was observed, with up to a factor of twenty-five times more Mg incorporated on the Ga-polarity. Measurements supported surface accumulation of Mg during growth, with stable accumulations of close to a monolayer of Mg. Mg coverage of a monolayer on the Ga-polarity induced a surface polarity inversion. Atomic hydrogen was found to increase the incorporation of Mg without also incorporating potentially compensating hydrogen.;Beryllium incorporation was also studied for both polarities of GaN. Unlike Mg, surface polarity-related incorporation differences were less pronounced for Be. Measurements also support surface accumulation of Be during growth, with stable accumulations approaching a monolayer for heavier doping levels. Transmission electron microscopy studies indicate the surface layer of Be has a significant effect on structure, with severe degradation occurring when accumulation nears monolayer coverage.;High-quality GaN films were grown to study the dependence of controlled oxygen incorporation on polarity and oxygen partial pressure. Oxygen concentrations up to 2.5 x 1022 cm-3 were obtained. About 10 times more oxygen incorporates on N-polar GaN than on the Ga-polarity in high quality epilayers. Oxygen doping is controllable, reproducible, and uncompensated up to concentrations of at least 1018 cm-3 with higher levels showing significant compensation. Layers with oxygen levels above 1022 cm-3 exhibit severe cracking. Oxygen incorporation has a weak dependence on Ga overpressure during Ga-stable growth but dramatically increases for conditions approaching N-stable growth.","abstract_html":"A reduced rate for growth of GaN by plasma-assisted molecular beam epitaxy often limits growth to temperatures less than 750°C, with the reduction significantly larger than thermal decomposition rates. Conditions producing a flux consisting predominantly of either atomic nitrogen or nitrogen metastables have been established using various rf-sources. Atomic nitrogen, possibly coupled with the presence of low energy ions, is associated with the premature decrease in growth rate. An active nitrogen flux consisting primarily of nitrogen metastables produces a temperature dependence more consistent with decomposition rates. Growth with molecular nitrogen metastables results in significantly improved electrical properties.;Magnesium incorporation was studied for both (0001), or Ga-polarity and (0001), or N-polarity, orientations for various growth conditions. A significant dependence on surface polarity of Mg incorporation was observed, with up to a factor of twenty-five times more Mg incorporated on the Ga-polarity. Measurements supported surface accumulation of Mg during growth, with stable accumulations of close to a monolayer of Mg. Mg coverage of a monolayer on the Ga-polarity induced a surface polarity inversion. Atomic hydrogen was found to increase the incorporation of Mg without also incorporating potentially compensating hydrogen.;Beryllium incorporation was also studied for both polarities of GaN. Unlike Mg, surface polarity-related incorporation differences were less pronounced for Be. Measurements also support surface accumulation of Be during growth, with stable accumulations approaching a monolayer for heavier doping levels. Transmission electron microscopy studies indicate the surface layer of Be has a significant effect on structure, with severe degradation occurring when accumulation nears monolayer coverage.;High-quality GaN films were grown to study the dependence of controlled oxygen incorporation on polarity and oxygen partial pressure. Oxygen concentrations up to 2.5 x 1022 cm-3 were obtained. About 10 times more oxygen incorporates on N-polar GaN than on the Ga-polarity in high quality epilayers. Oxygen doping is controllable, reproducible, and uncompensated up to concentrations of at least 1018 cm-3 with higher levels showing significant compensation. Layers with oxygen levels above 1022 cm-3 exhibit severe cracking. Oxygen incorporation has a weak dependence on Ga overpressure during Ga-stable growth but dramatically increases for conditions approaching N-stable growth.","abstract_has_math":false,"creators":["Ptak, Aaron Joseph"],"institution":null,"degree_name":"PhD","degree_level":"Dissertation","degree_discipline":"Physics and Astronomy","degree_department":null,"school":null,"contributors":["Thomas H. Myers."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2001,"date_issued":"2001-05-01T07:00:00Z","date_published":"2001-05-01T07:00:00Z","updated_at":"2026-07-24T06:15:40Z","subjects":["Condensed matter physics","Materials science"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://researchrepository.wvu.edu/etd/1351"],"render_values":[{"text":"https://researchrepository.wvu.edu/etd/1351","href":"https://researchrepository.wvu.edu/etd/1351","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.33915/etd.1351","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Thomas H. 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Conditions producing a flux consisting predominantly of either atomic nitrogen or nitrogen metastables have been established using various rf-sources. Atomic nitrogen, possibly coupled with the presence of low energy ions, is associated with the premature decrease in growth rate. An active nitrogen flux consisting primarily of nitrogen metastables produces a temperature dependence more consistent with decomposition rates. Growth with molecular nitrogen metastables results in significantly improved electrical properties.;Magnesium incorporation was studied for both (0001), or Ga-polarity and (0001), or N-polarity, orientations for various growth conditions. A significant dependence on surface polarity of Mg incorporation was observed, with up to a factor of twenty-five times more Mg incorporated on the Ga-polarity. Measurements supported surface accumulation of Mg during growth, with stable accumulations of close to a monolayer of Mg. Mg coverage of a monolayer on the Ga-polarity induced a surface polarity inversion. Atomic hydrogen was found to increase the incorporation of Mg without also incorporating potentially compensating hydrogen.;Beryllium incorporation was also studied for both polarities of GaN. Unlike Mg, surface polarity-related incorporation differences were less pronounced for Be. Measurements also support surface accumulation of Be during growth, with stable accumulations approaching a monolayer for heavier doping levels. Transmission electron microscopy studies indicate the surface layer of Be has a significant effect on structure, with severe degradation occurring when accumulation nears monolayer coverage.;High-quality GaN films were grown to study the dependence of controlled oxygen incorporation on polarity and oxygen partial pressure. Oxygen concentrations up to 2.5 x 1022 cm-3 were obtained. About 10 times more oxygen incorporates on N-polar GaN than on the Ga-polarity in high quality epilayers. Oxygen doping is controllable, reproducible, and uncompensated up to concentrations of at least 1018 cm-3 with higher levels showing significant compensation. Layers with oxygen levels above 1022 cm-3 exhibit severe cracking. Oxygen incorporation has a weak dependence on Ga overpressure during Ga-stable growth but dramatically increases for conditions approaching N-stable growth."]},{"key":"dc:title","label":"Title","values":["Growth kinetics and doping of gallium nitride grown by rf-plasma assisted molecular beam epitaxy"]}]}],"canonical_facts":{"dc:contributor":["Thomas H. Myers."],"dc:creator":["Ptak, Aaron Joseph"],"dc:date.available":["2019-01-17T08:00:00Z"],"dc:description.abstract":["A reduced rate for growth of GaN by plasma-assisted molecular beam epitaxy often limits growth to temperatures less than 750°C, with the reduction significantly larger than thermal decomposition rates. Conditions producing a flux consisting predominantly of either atomic nitrogen or nitrogen metastables have been established using various rf-sources. Atomic nitrogen, possibly coupled with the presence of low energy ions, is associated with the premature decrease in growth rate. An active nitrogen flux consisting primarily of nitrogen metastables produces a temperature dependence more consistent with decomposition rates. Growth with molecular nitrogen metastables results in significantly improved electrical properties.;Magnesium incorporation was studied for both (0001), or Ga-polarity and (0001), or N-polarity, orientations for various growth conditions. A significant dependence on surface polarity of Mg incorporation was observed, with up to a factor of twenty-five times more Mg incorporated on the Ga-polarity. Measurements supported surface accumulation of Mg during growth, with stable accumulations of close to a monolayer of Mg. Mg coverage of a monolayer on the Ga-polarity induced a surface polarity inversion. Atomic hydrogen was found to increase the incorporation of Mg without also incorporating potentially compensating hydrogen.;Beryllium incorporation was also studied for both polarities of GaN. Unlike Mg, surface polarity-related incorporation differences were less pronounced for Be. Measurements also support surface accumulation of Be during growth, with stable accumulations approaching a monolayer for heavier doping levels. Transmission electron microscopy studies indicate the surface layer of Be has a significant effect on structure, with severe degradation occurring when accumulation nears monolayer coverage.;High-quality GaN films were grown to study the dependence of controlled oxygen incorporation on polarity and oxygen partial pressure. Oxygen concentrations up to 2.5 x 1022 cm-3 were obtained. About 10 times more oxygen incorporates on N-polar GaN than on the Ga-polarity in high quality epilayers. Oxygen doping is controllable, reproducible, and uncompensated up to concentrations of at least 1018 cm-3 with higher levels showing significant compensation. Layers with oxygen levels above 1022 cm-3 exhibit severe cracking. Oxygen incorporation has a weak dependence on Ga overpressure during Ga-stable growth but dramatically increases for conditions approaching N-stable growth."],"dc:identifier":["https://doi.org/10.33915/etd.1351","https://researchrepository.wvu.edu/etd/1351"],"dc:subject":["Condensed matter physics","Materials science"],"dc:title":["Growth kinetics and doping of gallium nitride grown by rf-plasma assisted molecular beam epitaxy"],"thesis:degree_discipline":["Physics and Astronomy"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["PhD"]},"updated_at":"2026-07-24T06:15:40Z"}