{"id":{"repo_id":"ohiolink","oai_identifier":"oai:etd.ohiolink.edu:osu1365770655"},"canonical_url":"https://search.dev.ndltd.org/etd/ohiolink/oai:etd.ohiolink.edu:osu1365770655","repository":{"repo_id":"ohiolink","name":"OhioLINK","base_url":"https://etd.ohiolink.edu/acprod/odb_etd/ws/oai/oai"},"display":{"title":"Spectroscopic and Electrical Characterization of SiO<sub>x</sub> and GaN Device Structures as a Function of Irradiation","abstract":"Detecting irradiation and protecting complementary-metal-oxide-semiconductor (CMOS) devices from harsh radiation environments is vital for electronics in space and national security. For CMOS devices, ionizing photons have enough energy to break bonds within SiO<sub>2</sub> causing electrons, holes, and radiolytic protons to be released. Holes will be trapped in E-prime centers and non-bridging oxygen hole centers (NBOHC), whereas radiatiolytic protons will form more positively charged P<sub>b</sub> centers at the SiO<sub>2</sub>/Si interface. To combat positive charge build-up after ionizing irradiation, plasma enhanced chemical vapor deposited (PECVD) SiO<sub>x</sub> (x < 2) has been developed. PECVD SiO<sub>x</sub> contains evenly distributed nanocrystalline (nc)-Si grains or a-Si nanoclusters that trap electrons and inhibit radiolytic proton movement. We took flatband voltage shift (V<sub>FB</sub>) measurements after ionizing irradiation and found that V<sub>FB</sub> is less in PECVD SiO<sub>x</sub> than in SiO<sub>2</sub> because of the overall reduction in positive charge build-up. For as-deposited and annealed PECVD SiO<sub>x</sub>, spatially resolved depth resolved cathodoluminescence spectroscopy (DRCLS) and spectroscopic elipsometry confirmed a strong electron trap related to a-Si nanoclusters at 3.87 eV and nc-Si grains at 3.92 eV below the conduction band of SiO<sub>2</sub>, respectively. DRCLS after ionizing irradiation indicated that nc-Si grains are more efficient at trapping electrons. Finally, we observed that different plasma conditions for Si-rich SiO<sub>x</sub> produced an observed shift in the DRCLS electron trap energy, which may account for hysteresis degradation. Furthermore, understanding how neutron irradiation affects GaN material and diodes, especially at high fluences, is important for future implementation of in neutron sensor applications. Hence, GaN Schottky diodes were irradiated with thermal neutrons (25 meV) and fast neutrons (1 MeV) at three different fluences (10<sup>14</sup>, 10<sup>15</sup> and 10<sup>16</sup> n/cm<sup>2</sup>) and we measured resulting defects optically and electrically. Below 1015 n/cm2, neutron irradiation decreased the density of defects that give blue band (BB) and yellow band (YB) emissions in GaN, a sign that neutrons annealed and recrystallized GaN. At neutron fluences = 10<sup>15</sup> n/cm<sup>2</sup> the electrical properties of diodes degraded indicating 10<sup>14</sup> n/cm<sup>2</sup> is the threshold fluence before significant damage starts to occur. After = 10<sup>15</sup> fast neutron irradiation, the BB and YB GaN defects along with a radiation induced Ev + 1.4 eV trap state all increased near the surface. An increase in all three defects points to fast neutrons inducing regions of disorder in GaN. Moreover, fast + thermal neutrons exhibited the lowest forward I-V current and the highest sheet resistance, contact resistance, and ideality factor. However, the common GaN defects and Ev + 1.4 eV densities were lower than in the fast-only neutron case. These results suggested that thermal neutrons affected the metal contacts more than the GaN. Optical images, x-ray photoemission spectroscopy (XPS) and DRCLS showed that thermal neutrons induced oxygen and gallium rich localized melted regions that were insulating in nickel/GaN contacts. Thermal neutrons also caused nitrogen and gallium to incorporate into titanium, leaving semiconductor voids at the Ti/GaN interface.","abstract_html":"Detecting irradiation and protecting complementary-metal-oxide-semiconductor (CMOS) devices from harsh radiation environments is vital for electronics in space and national security. For CMOS devices, ionizing photons have enough energy to break bonds within SiO&lt;sub&gt;2&lt;/sub&gt; causing electrons, holes, and radiolytic protons to be released. Holes will be trapped in E-prime centers and non-bridging oxygen hole centers (NBOHC), whereas radiatiolytic protons will form more positively charged P&lt;sub&gt;b&lt;/sub&gt; centers at the SiO&lt;sub&gt;2&lt;/sub&gt;/Si interface. To combat positive charge build-up after ionizing irradiation, plasma enhanced chemical vapor deposited (PECVD) SiO&lt;sub&gt;x&lt;/sub&gt; (x &lt; 2) has been developed. PECVD SiO&lt;sub&gt;x&lt;/sub&gt; contains evenly distributed nanocrystalline (nc)-Si grains or a-Si nanoclusters that trap electrons and inhibit radiolytic proton movement. We took flatband voltage shift (V&lt;sub&gt;FB&lt;/sub&gt;) measurements after ionizing irradiation and found that V&lt;sub&gt;FB&lt;/sub&gt; is less in PECVD SiO&lt;sub&gt;x&lt;/sub&gt; than in SiO&lt;sub&gt;2&lt;/sub&gt; because of the overall reduction in positive charge build-up. For as-deposited and annealed PECVD SiO&lt;sub&gt;x&lt;/sub&gt;, spatially resolved depth resolved cathodoluminescence spectroscopy (DRCLS) and spectroscopic elipsometry confirmed a strong electron trap related to a-Si nanoclusters at 3.87 eV and nc-Si grains at 3.92 eV below the conduction band of SiO&lt;sub&gt;2&lt;/sub&gt;, respectively. DRCLS after ionizing irradiation indicated that nc-Si grains are more efficient at trapping electrons. Finally, we observed that different plasma conditions for Si-rich SiO&lt;sub&gt;x&lt;/sub&gt; produced an observed shift in the DRCLS electron trap energy, which may account for hysteresis degradation. Furthermore, understanding how neutron irradiation affects GaN material and diodes, especially at high fluences, is important for future implementation of in neutron sensor applications. Hence, GaN Schottky diodes were irradiated with thermal neutrons (25 meV) and fast neutrons (1 MeV) at three different fluences (10&lt;sup&gt;14&lt;/sup&gt;, 10&lt;sup&gt;15&lt;/sup&gt; and 10&lt;sup&gt;16&lt;/sup&gt; n/cm&lt;sup&gt;2&lt;/sup&gt;) and we measured resulting defects optically and electrically. Below 1015 n/cm2, neutron irradiation decreased the density of defects that give blue band (BB) and yellow band (YB) emissions in GaN, a sign that neutrons annealed and recrystallized GaN. At neutron fluences = 10&lt;sup&gt;15&lt;/sup&gt; n/cm&lt;sup&gt;2&lt;/sup&gt; the electrical properties of diodes degraded indicating 10&lt;sup&gt;14&lt;/sup&gt; n/cm&lt;sup&gt;2&lt;/sup&gt; is the threshold fluence before significant damage starts to occur. After = 10&lt;sup&gt;15&lt;/sup&gt; fast neutron irradiation, the BB and YB GaN defects along with a radiation induced Ev + 1.4 eV trap state all increased near the surface. An increase in all three defects points to fast neutrons inducing regions of disorder in GaN. Moreover, fast + thermal neutrons exhibited the lowest forward I-V current and the highest sheet resistance, contact resistance, and ideality factor. However, the common GaN defects and Ev + 1.4 eV densities were lower than in the fast-only neutron case. These results suggested that thermal neutrons affected the metal contacts more than the GaN. Optical images, x-ray photoemission spectroscopy (XPS) and DRCLS showed that thermal neutrons induced oxygen and gallium rich localized melted regions that were insulating in nickel/GaN contacts. Thermal neutrons also caused nitrogen and gallium to incorporate into titanium, leaving semiconductor voids at the Ti/GaN interface.","abstract_has_math":false,"creators":["Katz, Evan Jarrod"],"institution":"The Ohio State University","degree_name":"Doctor of Philosophy","degree_level":"doctoral","degree_discipline":"Electrical and Computer Engineering","degree_department":null,"school":null,"contributors":["Brillson, Leonard"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-07-23","date_published":"2013-07-23","updated_at":"2026-07-24T03:37:31Z","subjects":["Electrical Engineering"],"languages":["English"],"rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://rave.ohiolink.edu/etdc/view?acc_num=osu1365770655","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Brillson, Leonard"]},{"key":"dc:creator","label":"Author","values":["Katz, Evan Jarrod"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-07-23"]},{"key":"dc:publisher","label":"Institution","values":["The Ohio State University / OhioLINK"]},{"key":"dc:type","label":"Dc Type","values":["Electronic Thesis or Dissertation"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical and Computer Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["doctoral"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["The Ohio State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Electrical Engineering"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["English"]},{"key":"dc:rights","label":"Dc Rights","values":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://rave.ohiolink.edu/etdc/view?acc_num=osu1365770655"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Detecting irradiation and protecting complementary-metal-oxide-semiconductor (CMOS) devices from harsh radiation environments is vital for electronics in space and national security. For CMOS devices, ionizing photons have enough energy to break bonds within SiO<sub>2</sub> causing electrons, holes, and radiolytic protons to be released. Holes will be trapped in E-prime centers and non-bridging oxygen hole centers (NBOHC), whereas radiatiolytic protons will form more positively charged P<sub>b</sub> centers at the SiO<sub>2</sub>/Si interface. To combat positive charge build-up after ionizing irradiation, plasma enhanced chemical vapor deposited (PECVD) SiO<sub>x</sub> (x < 2) has been developed. PECVD SiO<sub>x</sub> contains evenly distributed nanocrystalline (nc)-Si grains or a-Si nanoclusters that trap electrons and inhibit radiolytic proton movement. We took flatband voltage shift (V<sub>FB</sub>) measurements after ionizing irradiation and found that V<sub>FB</sub> is less in PECVD SiO<sub>x</sub> than in SiO<sub>2</sub> because of the overall reduction in positive charge build-up. For as-deposited and annealed PECVD SiO<sub>x</sub>, spatially resolved depth resolved cathodoluminescence spectroscopy (DRCLS) and spectroscopic elipsometry confirmed a strong electron trap related to a-Si nanoclusters at 3.87 eV and nc-Si grains at 3.92 eV below the conduction band of SiO<sub>2</sub>, respectively. DRCLS after ionizing irradiation indicated that nc-Si grains are more efficient at trapping electrons. Finally, we observed that different plasma conditions for Si-rich SiO<sub>x</sub> produced an observed shift in the DRCLS electron trap energy, which may account for hysteresis degradation. Furthermore, understanding how neutron irradiation affects GaN material and diodes, especially at high fluences, is important for future implementation of in neutron sensor applications. Hence, GaN Schottky diodes were irradiated with thermal neutrons (25 meV) and fast neutrons (1 MeV) at three different fluences (10<sup>14</sup>, 10<sup>15</sup> and 10<sup>16</sup> n/cm<sup>2</sup>) and we measured resulting defects optically and electrically. Below 1015 n/cm2, neutron irradiation decreased the density of defects that give blue band (BB) and yellow band (YB) emissions in GaN, a sign that neutrons annealed and recrystallized GaN. At neutron fluences = 10<sup>15</sup> n/cm<sup>2</sup> the electrical properties of diodes degraded indicating 10<sup>14</sup> n/cm<sup>2</sup> is the threshold fluence before significant damage starts to occur. After = 10<sup>15</sup> fast neutron irradiation, the BB and YB GaN defects along with a radiation induced Ev + 1.4 eV trap state all increased near the surface. An increase in all three defects points to fast neutrons inducing regions of disorder in GaN. Moreover, fast + thermal neutrons exhibited the lowest forward I-V current and the highest sheet resistance, contact resistance, and ideality factor. However, the common GaN defects and Ev + 1.4 eV densities were lower than in the fast-only neutron case. These results suggested that thermal neutrons affected the metal contacts more than the GaN. Optical images, x-ray photoemission spectroscopy (XPS) and DRCLS showed that thermal neutrons induced oxygen and gallium rich localized melted regions that were insulating in nickel/GaN contacts. Thermal neutrons also caused nitrogen and gallium to incorporate into titanium, leaving semiconductor voids at the Ti/GaN interface."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf","p.187","11.28 MB"]},{"key":"dc:title","label":"Title","values":["Spectroscopic and Electrical Characterization of SiO<sub>x</sub> and GaN Device Structures as a Function of Irradiation"]}]}],"canonical_facts":{"dc:contributor":["Brillson, Leonard"],"dc:creator":["Katz, Evan Jarrod"],"dc:date":["2013-07-23"],"dc:description":["Detecting irradiation and protecting complementary-metal-oxide-semiconductor (CMOS) devices from harsh radiation environments is vital for electronics in space and national security. For CMOS devices, ionizing photons have enough energy to break bonds within SiO<sub>2</sub> causing electrons, holes, and radiolytic protons to be released. Holes will be trapped in E-prime centers and non-bridging oxygen hole centers (NBOHC), whereas radiatiolytic protons will form more positively charged P<sub>b</sub> centers at the SiO<sub>2</sub>/Si interface. To combat positive charge build-up after ionizing irradiation, plasma enhanced chemical vapor deposited (PECVD) SiO<sub>x</sub> (x < 2) has been developed. PECVD SiO<sub>x</sub> contains evenly distributed nanocrystalline (nc)-Si grains or a-Si nanoclusters that trap electrons and inhibit radiolytic proton movement. We took flatband voltage shift (V<sub>FB</sub>) measurements after ionizing irradiation and found that V<sub>FB</sub> is less in PECVD SiO<sub>x</sub> than in SiO<sub>2</sub> because of the overall reduction in positive charge build-up. For as-deposited and annealed PECVD SiO<sub>x</sub>, spatially resolved depth resolved cathodoluminescence spectroscopy (DRCLS) and spectroscopic elipsometry confirmed a strong electron trap related to a-Si nanoclusters at 3.87 eV and nc-Si grains at 3.92 eV below the conduction band of SiO<sub>2</sub>, respectively. DRCLS after ionizing irradiation indicated that nc-Si grains are more efficient at trapping electrons. Finally, we observed that different plasma conditions for Si-rich SiO<sub>x</sub> produced an observed shift in the DRCLS electron trap energy, which may account for hysteresis degradation. Furthermore, understanding how neutron irradiation affects GaN material and diodes, especially at high fluences, is important for future implementation of in neutron sensor applications. Hence, GaN Schottky diodes were irradiated with thermal neutrons (25 meV) and fast neutrons (1 MeV) at three different fluences (10<sup>14</sup>, 10<sup>15</sup> and 10<sup>16</sup> n/cm<sup>2</sup>) and we measured resulting defects optically and electrically. Below 1015 n/cm2, neutron irradiation decreased the density of defects that give blue band (BB) and yellow band (YB) emissions in GaN, a sign that neutrons annealed and recrystallized GaN. At neutron fluences = 10<sup>15</sup> n/cm<sup>2</sup> the electrical properties of diodes degraded indicating 10<sup>14</sup> n/cm<sup>2</sup> is the threshold fluence before significant damage starts to occur. After = 10<sup>15</sup> fast neutron irradiation, the BB and YB GaN defects along with a radiation induced Ev + 1.4 eV trap state all increased near the surface. An increase in all three defects points to fast neutrons inducing regions of disorder in GaN. Moreover, fast + thermal neutrons exhibited the lowest forward I-V current and the highest sheet resistance, contact resistance, and ideality factor. However, the common GaN defects and Ev + 1.4 eV densities were lower than in the fast-only neutron case. These results suggested that thermal neutrons affected the metal contacts more than the GaN. Optical images, x-ray photoemission spectroscopy (XPS) and DRCLS showed that thermal neutrons induced oxygen and gallium rich localized melted regions that were insulating in nickel/GaN contacts. Thermal neutrons also caused nitrogen and gallium to incorporate into titanium, leaving semiconductor voids at the Ti/GaN interface."],"dc:format":["application/pdf","p.187","11.28 MB"],"dc:identifier":["http://rave.ohiolink.edu/etdc/view?acc_num=osu1365770655"],"dc:language":["English"],"dc:publisher":["The Ohio State University / OhioLINK"],"dc:rights":["unrestricted","This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws."],"dc:subject":["Electrical Engineering"],"dc:title":["Spectroscopic and Electrical Characterization of SiO<sub>x</sub> and GaN Device Structures as a Function of Irradiation"],"dc:type":["Electronic Thesis or Dissertation"],"thesis:degree_discipline":["Electrical and Computer Engineering"],"thesis:degree_level":["doctoral"],"thesis:degree_name":["Doctor of Philosophy"],"thesis:institution_name":["The Ohio State University"]},"updated_at":"2026-07-24T03:37:31Z"}