| 摘要 |
PROBLEM TO BE SOLVED: To remove a surface part which is mechanically damaged and to form a projecting/recessed structure for confining light with a one-time etching by executing special etching on a silicon substrate having a rough face sliced by mechanical processing. SOLUTION: For removing a first surface part 7 of a silicon substrate 1, sodium silicate is dissolved in water and is subjected to etching by the use of an aqueous solution, for example. Sodium silicate is used for etching and dissociation to ions does not proceed completely in sodium silicate. This largely contributes not only to the deceleration of etching speed but also to the form of an etched surface, and a desired ruggedness form can be obtained. The mechanically damaged surface part can be removed, and a ruggedness structure which is effective for confining light can be formed with one etching only by the etching, namely, by a primary etching process. |
