期刊
PHILOSOPHICAL MAGAZINE
卷 94, 期 34, 页码 3898-3913出版社
TAYLOR & FRANCIS LTD
DOI: 10.1080/14786435.2014.968230
关键词
volume swelling.; annealing; silicon carbide; ion irradiation; Raman spectroscopy; recrystallization
Silicon carbide (SiC) single crystals with the 6H polytype structure were irradiated with 4.0-MeV Au ions at room temperature (RT) for increasing fluences ranging from 1 x 10(12) to 2 x 10(15)cm(-2), corresponding to irradiation doses from ~0.03 to 5.3 displacements per atom (dpa). The damage build-up was studied by micro-Raman spectroscopy that shows a progressive amorphization by the decrease and broadening of 6H-SiC lattice phonon peaks and the related growth of bands assigned to Si-Si and C-C homonuclear bonds. A saturation of the lattice damage fraction deduced from Raman spectra is found for ~0.8 dpa (i.e. ion fluence of 3 x 10(14)cm(-2)). This process is accompanied by an increase and saturation of the out-of-plane expansion (also for ~0.8 dpa), deduced from the step height at the sample surface, as measured by phase-shift interferometry. Isochronal thermal annealing experiments were then performed on partially amorphous (from 30 to 90%) and fully amorphous samples for temperatures from 200 degrees C up to 1500 degrees C under vacuum. Damage recovery and densification take place at the same annealing stage with an onset temperature of ~200 degrees C. Almost complete 6H polytype regrowth is found for partially amorphous samples (for doses lower than 0.8 dpa) at 1000 degrees C, whereas a residual damage and swelling remain for larger doses. In the latter case, these unrelaxed internal stresses give rise to an exfoliation process for higher annealing temperatures.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据