| 摘要 |
A silicon epitaxial layer 2 is grown in vapor phase on a silicon single crystal substrate 1 manufactured by the Czochralski method, and doped with boron so as to adjust the resistivity to 0.02 Omega.cm or below, oxygen precipitation nuclei 11 are formed in the silicon single crystal substrate 1, by carrying out annealing at 450° C. to 750° C., in an oxidizing atmosphere, for a duration of time allowing formation of a silicon oxide film only to as thick as 2 nm or below on the silicon epitaxial layer 2 as a result of the annealing, and thus-formed silicon oxide film 3 is etched as the first cleaning after the low-temperature annealing, using a cleaning solution. By this process, the final residual thickness of the silicon oxide film can be suppressed only to a level equivalent to native oxide film, without relying upon the hydrofluoric acid cleaning.
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