Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing
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The Ohio State University / OhioLINK
2006
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ndltd-OhioLink-oai-etd.ohiolink.edu-osu11413253022021-08-03T05:50:47Z Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing White, Brad D. Gallium Nitride GaN AlGaN HEMT Schottky Barrier Proton Irradiation Device Processing ICP-RIE Fermi Level Pinning Defects Cathodoluminescence Spatially-resolved cathodoluminescence spectroscopy (CLS) has been used to identify the presence of radiative point and extended defects in the semiconductor band gap produced by irradiation and processing conditions for Si and GaN-based devices. Changes in deep level emission in Al-SiO <sub>2</sub> -Si capacitor structures revealed a gradient in relative defect concentrations across the SiO <sub>2</sub> film after x-ray irradiation, indicating interface-specific defect creation. CLS measurements also revealed changes in the near-band edge signatures of AlGaN-GaN high-electron mobility transistor (HEMT) structures subjected to 1.8 MeV proton irradiation. These changes were indicative of alloying of AlGaN and GaN at the charge confinement interface and relaxation of piezoelectric strain in the AlGaN film. Alloying was confirmed with secondary-ion mass spectrometry, and each mechanism contributed to the measured degradation in HEMT channel transport properties. Ni-GaN Schottky barrier height decreases were also observed at lower fluences. 1.0 MeV protons were ~1.5 times more damaging than 1.8 MeV protons, which is consistent with simulations of total non-ionizing energy loss. Schottky contacts on x <sub>Al</sub> ~0.4 AlGaN were also investigated versus pre-deposition cleaning procedure. Two inductively-coupled plasma reactive-ion etching (ICP-RIE) procedures were compared with a standard HCl etch. The ICP-RIE treated samples exhibited higher uniformity than the HCl-etched surface, from electrical and CLS measurements. The presence of a spectral emission at in the HCl-etched piece correlated with the presence of a secondary Schottky barrier at ~1 eV. The emergence of a second spectral peak after ICP treatment also resulted in pinned barriers near 1 eV. A pre-metallization rapid-thermal annealing process after the ICP-RIE treatment resulted in the disappearance of both peaks, and correlated with the best diode electrical properties. The degree of Fermi level pinning from interface states, inferred from plots of extracted barrier height versus metal workfunction, was characterized for all processing conditions. Estimated interface state density was reduced by an order of magnitude for the rapid-thermal anneal process. Temperature-dependent CLS was used to assign physical origins to the defects that control the Schottky barrier properties. Nitrogen vacancies are the most probable assignment for one, or both, peaks, with the presence of screw dislocations suggested by the data. 2006-03-15 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1141325302 http://rave.ohiolink.edu/etdc/view?acc_num=osu1141325302 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. |
| collection |
NDLTD |
| language |
English |
| sources |
NDLTD |
| topic |
Gallium Nitride GaN AlGaN HEMT Schottky Barrier Proton Irradiation Device Processing ICP-RIE Fermi Level Pinning Defects Cathodoluminescence |
| spellingShingle |
Gallium Nitride GaN AlGaN HEMT Schottky Barrier Proton Irradiation Device Processing ICP-RIE Fermi Level Pinning Defects Cathodoluminescence White, Brad D. Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing |
| author |
White, Brad D. |
| author_facet |
White, Brad D. |
| author_sort |
White, Brad D. |
| title |
Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing |
| title_short |
Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing |
| title_full |
Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing |
| title_fullStr |
Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing |
| title_full_unstemmed |
Cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing |
| title_sort |
cathodoluminescence spectroscopy studies of aluminum gallium nitride and silicon device structures as a function of irradiation and processing |
| publisher |
The Ohio State University / OhioLINK |
| publishDate |
2006 |
| url |
http://rave.ohiolink.edu/etdc/view?acc_num=osu1141325302 |
| work_keys_str_mv |
AT whitebradd cathodoluminescencespectroscopystudiesofaluminumgalliumnitrideandsilicondevicestructuresasafunctionofirradiationandprocessing |
| _version_ |
1719426453819359232 |