Recrystallization-Induced Surface Cracks of Carbon Ions Irradiated 6H-SiC after Annealing

Abstract

Single crystal 6H-SiC wafers with 4° off-axis [0001] orientation were irradiated with carbon ions and then annealed at 900 °C for different time periods. The microstructure and surface morphology of these samples were investigated by grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Ion irradiation induced SiC amorphization, but the surface was smooth and did not have special structures. During the annealing process, the amorphous SiC was recrystallized to form columnar crystals that had a large amount of twin structures. The longer the annealing time was, the greater the amount of recrystallized SiC would be. The recrystallization volume fraction was accorded with the law of the Johnson–Mehl–Avrami equation. The surface morphology consisted of tiny pieces with an average width of approximately 30 nm in the annealed SiC. The volume shrinkage of irradiated SiC layer and the anisotropy of newly born crystals during annealing process produced internal stress and then induced not only a large number of dislocation walls in the non-irradiated layer but also the initiation and propagation of the cracks. The direction of dislocation walls was perpendicular to the growth direction of the columnar crystal. The longer the annealing time was, the larger the length and width of the formed crack would be. A quantitative model of the crack growth was provided to calculate the length and width of the cracks at a given annealing time.

MD simulation study on defect evolution and doping efficiency of p-type doping of 3C-SiC by Al ion implantation with subsequent annealing

“…In experimental research of recent years, Jones [82,83] uncovered an interstitial type dislocation called end-of-range (EOR) damage through TEM micrographs, just below the crystalline / amorphous interface by Ge + -implanted silicon. Ye et al [84] illustrated recrystallization process of carbon irradiated 6H-SiC, and found the volume shrinkage and the anisotropy of the new born crystal during annealing process generated internal stress, which not only produced a large number of dislocation walls but also caused the initiation and propagation of cracks. Hence, the crack propagation or glide of pre-existing basal-plane dislocations can be suppressed by improving the temperature gradient inside the annealing furnace in actual processing [85].…”

Dissolution corrosion of 4H‐SiC in lead‐bismuth eutectic at 550°C

“…Owing to the advanced physical and chemical stability properties, silicon carbide (SiC) and SiC‐fiber‐reinforced SiC matrix composites, have been regarded as a promising material for advanced nuclear energy application . It has been extensively investigated irradiation effects in the high purity SiC and composite, including neutron, ion, and electron irradiation . In addition, the corrosion resistance of the SiC materials has been investigated in the high‐pressure and high‐temperature water and molten salt …”

Effect of Shear Stress on Isothermal Crystallization Behavior of CaO-Al2O3-SiO2-Na2O-CaF2 Slags

“…The kinetics of mold flux isothermal crystallization involving nucleation and growth are analyzed through the Johnson–Mehl–Avrami (JMA) model [27,28,29,30]. According to the JMA model, the volume fraction of crystals X ( t ) is given by:$Xfalse(tfalse)=1-\exp false(-k{t}^{n}false)$ where X ( t ) is the relative degree of crystallinity at a given time t , including the incubation time, n is the Avrami exponent, which is associated with the nucleation and growth mechanism, and k is the effective crystallization rate constant, which is dependent on the temperature and the rate of nucleation and crystal growth.…”