| 摘要 |
PURPOSE:To improve a leakage current restraining effect by making a width of the vicinity of the upper end of a stripe region wider than a width of an active layer and making an interval between the outer sides of a current constriction region nearly the same as the width of the vicinity of the upper end of the stripe region. CONSTITUTION:The stripe region including an active layer 3 and a pair of current constriction regions contacting the stripe region 3 provided with p-n reverse junction are arranged to define a width of the upper end portion of the stripe region wider than that of the active layer 3 and the interval of the outer planes of the current constriction region nearly the same as the width of the upper end portion of the stripe region. For example, on the substrate which is composed of an n-type InP substrate 1 on which an n-type InP enclosure layer 2, a non-doped InGaAsP active layer 3, a p-type InP enclosure layer 4, and a p<+>-type InGaAsP cap layer 5 are epitaxially grown, a stripe region is formed and in its cross section, a width of the upper end portion is determined to be 3.5-5mum whereas that of the active layer is determined to be 1-2mum. On this semiconductor substrate, a p-type InP layer 7, an n-type InP layer 8, and a p-type InGaAsP layer 9 are buried-grown and the interval between the outer sides of the current constriction region composed of the InP layers 8 and 7 is almost equalized to a width of the upper end of the stripe region.
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