Vacancy effects on the formation of He and Kr cavities in 3C-SiC irradiated and annealed at elevated temperatures

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Beam interactions with materials and atoms, 2016-12, Vol.389-390 (C), p.40-47
• Main Authors: Zang, Hang, Jiang, Weilin, Liu, Wenbo, Devaraj, Arun, Edwards, Danny J., Henager, Charles H., Kurtz, Richard J., Li, Tao, He, Chaohui, Yun, Di, Wang, Zhiguang
• Format: Article
• Language: English
• Subjects: 3C-SiC; Cavity Formation; Environmental Molecular Sciences Laboratory; He and Kr cavities; High-temperature annealing; Ion implantation; Ion irradiation; NUCLEAR PHYSICS AND RADIATION PHYSICS; SiC; Vacancy effect
• ISSN: 0168-583X; 1872-9584
• DOI: 10.1016/j.nimb.2016.11.017

•He and Kr cavities are formed in ion-implanted and 1600°C annealed 3C-SiC.•A higher vacancy concentration leads to formation of cavities with a smaller size and higher density.•Presence of He in irradiated 3C-SiC can significantly promote cavity growth.•Small voids are formed in Kr ion penetrated 3C-SiC during thermal annealing at 1600°C.•Local Kr migration and trapping at cavities in SiC are observed, but long-range Kr diffusion does not occur at 1600°C. Polycrystalline 3C-SiC was sequentially irradiated at 400 and 750°C with 120keV He2+ and 4MeV Kr15+ ions to 1017 and 4×1016cm−2, respectively. The Kr15+ ions penetrated the entire depth region of the He2+ ion implantation. Three areas of He2+, Kr15+ and He2++Kr15+ ion implanted SiC were created through masked overlapping irradiation. The sample was subsequently annealed at 1600°C in vacuum and characterized using cross-sectional transmission electron microscopy and energy-dispersive X-ray spectroscopy. Compared to the He2+ ion only implanted SiC, He cavities show a smaller size and higher density in the co-implanted SiC. At 25dpa, presence of He in the co-implanted 3C-SiC significantly promotes cavity growth; much smaller voids are formed in the Kr15+ ion only irradiated SiC at the same dose. In addition, local Kr migration and trapping at cavities occurs, but long-range Kr diffusion in SiC is not observed up to 1600°C.