Atomic resolution analysis of extended defects and Mg agglomeration in Mg-ion-implanted GaN and their impacts on acceptor formation
| Autor: | Emi Kano, Keita Kataoka, Jun Uzuhashi, Kenta Chokawa, Hideki Sakurai, Akira Uedono, Tetsuo Narita, Kacper Sierakowski, Michal Bockowski, Ritsuo Otsuki, Koki Kobayashi, Yuta Itoh, Masahiro Nagao, Tadakatsu Ohkubo, Kazuhiro Hono, Jun Suda, Tetsu Kachi, Nobuyuki Ikarashi |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 132:065703 |
| ISSN: | 1089-7550 0021-8979 |
| Popis: | We carried out atomic-scale observations of Mg-ion-implanted GaN by transmission electron microscopy (TEM) and atom probe tomography (APT) to clarify the crystallographic structures of extended defects and Mg agglomerations that form during post-implantation annealing. The complementary TEM and APT analyses have shown that Mg atoms agglomerate at dislocations that bound extended defects. The concentration of Mg is higher at the dislocations with a larger Burgers vector. This indicates that Mg agglomeration is caused by the pressure at the dislocations. Mg concentration in highly Mg-rich regions is 1 at. %, which exceeds the solubility limit of Mg in GaN. We investigated isothermal and isochronal evolution of the defects by TEM, cathodoluminescence analysis, and positron annihilation spectroscopy. The results indicated that the intensity of donor–acceptor pair emission increases with the annealing temperature and duration and reaches a maximum after elimination of the extended defects with highly Mg-rich regions. These results strongly suggest that such extended defects reduce the acceptor formation and that they as well as the previously reported compensating centers, such as N-related vacancies, can inhibit the formation of p-type GaN. The mechanism by which the extended defects reduce acceptor formation is discussed. |
| Databáze: | OpenAIRE |
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