| 摘要 |
PURPOSE:To decrease a current flowing a part other than an active layer to the large extent, by embedding and growing a plurality of P-N junction layers, which have larger forbidden band width than the forbidden band widths of P type InP and N type InP or the active layer. CONSTITUTION:On an N type InP substrate 1, the following layers are laminated; an N type InP lightguide layer 2, an N or P type InGaAsP active layer 3 which has a smaller forbidden band widht than that of the layer 2, a P type InP lightguide layer 4 and a P type InGaAsP cap layer 5 which has a forbidden band width larger than that of the layer 3 and smaller than that of the layer 4. Then, a stripe shaped mask 6 is formed on the layer 5. The area, which is not covered by the mask 6, is etched to a part of the layer 2 by mesa etching. Then, a plurality of P-N junctions layers 7 are embedded and laminated in the etched region. Thereafter, the mask 6 is removed, and a P<+> diffused layer 8 reaching a part of the layer 4 is formed in this part. Electrodes 9 and 10 are formed on the surface including the layer 8 and the back surface of the substrate 1, respectively. In this way, a current flowing a part other than the layer 3 is largely decreased, and the elongation of a life is implemented. |
