| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a semiconductor element, manufacturing a diffraction grating having its depth (coupling coefficient) easily changing to suppress the concavity and convexity on the surface of the diffraction grating of a manufactured element, and thereby decreasing an optical loss and showing characteristics of a side mode being suppressed. SOLUTION: An SiO2 mask 1803 having the opening part changing its width is formed on an InGaAsP waveguide layer 1801. When RIE (reactive ion etching) is performed using a mixed gas of methane and hydrogen with a methane flow volume of 40 sccm, a hydrogen flow volume of 5 sccm, an electric discharge power of 100 W, and a gas pressure of 40 Pa, etching is promoted at a first opening part 1804 having a width of 1.8μm to generates polymer on the surface of a second opening part 1805 and a third opening part 1806 without causing concavity and convexity (Fig. 7(b)). Successively, oxygen plasma is irradiated under an oxygen volume of 10 sccm, a gas pressure of 10 Pa, and a discharge power of 400 W, for one minute to remove the deposited polymer (Fig. 7(c)). COPYRIGHT: (C)2011,JPO&INPIT
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