The effect of reactor neutron irradiation on the etch rate of SiC in potassium hydroxide has been studied. In the case of high irradiation doses (1019–1021 cm–2), the etch rate of silicon carbide has been shown to drastically rise, especially in the [0001]Si direction. This considerably mitigates the orientation anisotropy of polar face etching. After high-temperature annealing (up to 1200–1400°C), a higher etch rate of irradiated crystals persists. The results have been explained by the high concentration of radiation-induced (partially clustered) defects they contain.
相似文献The ray method of calculating the mode amplitudes is used to analyze the sound fields in deep-water acoustic waveguides with two types of inhomogeneities of the refractive index: (i) weak inhomogeneities that cause small perturbations of ray trajectories and (ii) strong inhomogeneities with large spatial scales. Simple analytical relations are derived for describing the variations of the mode structure of the sound field in the presence of the aforementioned inhomogeneities. A new criterion defining the validity of the adiabatic approximation is formulated. To illustrate and test the results obtained, a numerical simulation of the sound fields is performed on the basis of the parabolic equation method.
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