Voids and vacancy-type defects in SiO2/GaN structures probed by monoenergetic positron beams
| Autor: | Wataru Ueno, Takahiro Yamada, Marcel Dickmann, Tönjes Koschine, Werner Egger, Akira Uedono, Takuji Hosoi, Christoph Hugenschmidt, Heiji Watanabe |
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| Rok vydání: | 2020 |
| Předmět: |
010302 applied physics
Materials science Chemical substance business.industry Annealing (metallurgy) General Physics and Astronomy 02 engineering and technology Chemical vapor deposition 021001 nanoscience & nanotechnology 01 natural sciences Positron Impurity Desorption Vacancy defect 0103 physical sciences Optoelectronics 0210 nano-technology business Science technology and society |
| Zdroj: | Journal of Applied Physics. 127:054503 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.5134513 |
| Popis: | Voids in SiO2 films deposited on GaN were probed by using monoenergetic positron beams. The films were fabricated on GaN substrates by using plasma-enhanced chemical vapor deposition. The size and density of the voids in the films increased up to an annealing temperature of 800 °C and then decreased at 1000 °C. The observed annealing behaviors of the voids were attributed to the desorption of impurities incorporated during the deposition process and the shrinkage of the Si–O matrix by high-temperature annealing. Vacancy-type defects were introduced into the GaN substrate after 1000 °C annealing in O2 atmosphere due to the diffusion of Ga from the substrate to the SiO2 film. No out-diffusion of Ga into the SiO2 film was observed for the annealing in N2 atmosphere. Thus, the observed out-diffusion of Ga was attributed to the enhanced oxidation of GaN during the annealing in O2 atmosphere. The diffusion of positrons implanted into the GaN substrate toward the SiO2 film was suppressed by annealing, suggesting a decrease in the negative charges in the SiO2 film or near the SiO2/GaN interface. |
| Databáze: | OpenAIRE |
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