| 摘要 |
A method of selective etching, characterized in that a silicon single crystal substrate of < 10 mOmega . cm electric resistivity is etched with the use of a selective etchant containing at least, in terms of volume composition, 0.02 to 0.1 of hydrofluoric acid, 0.5 to 0.6 of nitric acid, 0.2 to 0.25 of acetic acid and water at a rate greater than 0.1 mum/min so as to manifest BMD on the surface of the silicon single crystal substrate. Thus, there can be provided a method of selective etching, in which the characteristics of crystal defects, in particular, BMD of ultralow resistivity silicon single crystal substrate of < 10 mOmega . cm electric resistivity whose easy detection has been infeasible can be assessed and utilized through the selective etching using a chromium-free etchant wherein no harmful chromium is contained.
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