| 摘要 |
PURPOSE:To form a stripe trench of a required form with excellent reproducibility by a method wherein an InGaAsP layer, which is a four-element layer, is selectively etched by dry-etching. CONSTITUTION:A P-type InP layer 21, an N-type InP layer 22 and a P-type InP layer 23 are successively built up by an LPE method on a P-type InP substrate 20 and then an InGaAsP layer 24 is made to grow on the P-type InP layer 23 and a resist film 25 with an aperture 26 is formed on the InGaAsP layer 24. An aperture 27 is formed in the InGaAsP layer 24 by dry-etching with the resist film 25 as a mask. Then, with the InGaAsP layer 24 as a mask, the two-element layers 23...21 directly below the aperture 27 are selectively etched to form a stripe shape aperture 28 with an approximately arrowhead- shape cross section. With this constitution, a stripe trench 29 with an arrowhead- shape cross section can be formed with excellent reproducibility.
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