In-situ observation of damage evolution in SiC crystals during He+ and H2+ dual-ion beam irradiation

Hojou, K.; Furuno, S.; Kushita, Kouhei N.; Otsu, Hiroshi; Izui, K.

doi:10.1016/s0022-3115(09)80113-x

Cited by 26 publications

(16 citation statements)

References 5 publications

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“…Hot-pressed SiC of Ϸ98.5% purity and 3.2 g/cm 3 density was supplied in sheets of Ϸ350 m by Elektroschmelzwerk Kempten. X-ray analysis gave 80% 6H-SiC, 18% 4H-SiC, and Ϸ2% free carbon, while transmission electron microscopy ͑TEM͒ in addition revealed small amounts of 3C-SiC ͑␤-SiC͒ and 15R-SiC.…”

Section: Methodsmentioning

confidence: 99%

“…In the latter case helium is produced by nuclear transmutations while in semiconductors introduction of helium is proposed for gettering impurities. Previous investigations on helium-induced microstructural changes in SiC were confined to either shallow implantation of helium ions in the keV range [1][2][3] or neutron irradiation of boron-doped material. [4][5][6][7][8][9] In the present work, ␣ particles with energies from 0 to Ϸ25 MeV were implanted homogeneously up to depths of mostly Ϸ100 m. Therefore the results are not affected by surfaces ͑from shallow implantation͒ or grain boundaries ͑from boron segregation͒.…”

Section: Introductionmentioning

confidence: 99%

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Microstructural evolution of helium-implanted α-SiC

2000

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Helium has a decisive effect on the microstructure of silicon carbide materials after implantation and subsequent annealing. A dense population of bubbles and dislocation loops is already observed at relatively low displacement doses after annealing of helium-implanted ␣-SiC, while no visible damage appears after irradiation without helium implantation under otherwise equal conditions. The defects are separated from grain boundaries by defect-free zones of approximately 0.5 m width. The most intriguing features of the evolving microstructure are lenticular cavities ͑platelets͒, which transform to disk-shaped arrangements of bubbles with associated dislocation loops or even stacks of loops. The observed microstructural evolution and its dependence on implantation dose, annealing temperature, and time are quantitatively explained and discussed in terms of diffusion of interstitial He atoms and their clustering between adjacent lattice planes, thus forming nanocracks during implantation. The relaxation of the high gas pressure by matrix atom transfer from bubbles to loops during annealing and the coarsening of bubble-loop complexes are described by a coupled twocomponent Ostwald ripening process.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microstructural evolution of helium-implanted α-SiC

2000

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“…Hojou et al [90] found that formation of cavities in a-SiC at room temperature required a 15-keV H ion fluence of $5 Â 10 22 m À2 , which was about fifty times higher than the corresponding fluence for low energy He ion irradiation. Muto et al [75] reported relatively high fluences ($1-3 Â 10 22 m À2 ; $100 at.% implanted gas) for inducing visible cavity formation in SiC irradiated at room temperature with either low-energy (12-19 keV) H or He ions, with threshold H concentrations about double the corresponding threshold He concentrations.…”

Section: Threshold H Concentrations For Visible Cavity Formationmentioning

confidence: 99%

Effect of H and He irradiation on cavity formation and blistering in ceramics

Zinkle

2012

Nuclear Instruments and Methods in Physics Research Section B:

105

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“…It also occurs in SiC (e.g. [219 -221]) with He bubble formation being enhanced by simultaneous H + implantation [222]. He bubbles/blisters are different to hydrogen blisters and require less fluence to form.…”

Section: S Agmentioning

confidence: 99%

Diffusion of fission products and radiation damage in SiC

Malherbe

2013

J. Phys. D: Appl. Phys.

102

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A major problem with most of the present nuclear reactors is their safety in terms of the release of radioactivity into the environment during accidents. In some of the future nuclear reactor designs, i.e. Generation IV reactors, the fuel is in the form of coated spherical particles, i.e. TRISO (acronym for Triple Coated Isotropic) particles. The main function of these coating layers is to act as diffusion barriers for radioactive fission products, thereby keeping these fission products within the fuel particles, even under accident conditions. The most important coating layer is composed of polycrystalline 3C-SiC. This paper reviews the diffusion of the important fission products (silver, caesium, iodine and strontium) in SiC. Because radiation damage can induce and enhance diffusion, the paper also briefly reviews damage created by energetic neutrons and ions at elevated temperatures, i.e. the temperatures at which the modern reactors will operate, and the annealing of the damage. The interaction between SiC and some fission products (such as Pd and I) is also briefly discussed. As shown, one of the key advantages of SiC is its radiation hardness at elevated temperatures, i.e. SiC is not amorphized by neutron or bombardment at substrate temperatures above 350°C. Based on the diffusion coefficients of the fission products considered, the review shows that at the normal operating temperatures of these new reactors (i.e. less than 950°C) the SiC coating layer is a good diffusion barrier for these fission products. However, at higher temperatures the design of the coated particles needs to be adapted, possibly by adding a thin layer of ZrC.

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In-situ observation of damage evolution in SiC crystals during He+ and H2+ dual-ion beam irradiation

Cited by 26 publications

References 5 publications

Microstructural evolution of helium-implanted α-SiC

Microstructural evolution of helium-implanted α-SiC

Effect of H and He irradiation on cavity formation and blistering in ceramics

Diffusion of fission products and radiation damage in SiC

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