| 摘要 |
PURPOSE:To make coupling efficiency with optical fiber excellent and to obtain an element having excellent reliability for a long time, by partially removing a rear surface to the interface between an active layer and a buffer layer, forming a doughnut shaped recess part around a part, which is to become a light emitting region, and providing electrodes at the central remaining part surrounded by the recess part and on the other surface of a substrate. CONSTITUTION:On the rear surface of an n-InP substrate 10, an n-InP layer (buffer layer) 11, an InGaAsP layer (active layer) 12, a p-InP layer 13, and a p-InGaAsP layer (cap layer) are epitaxially grown sequentially. Then etching is performed from the rear surface side, and a doughnut shaped recess part 21 is formed. At this time, a part to the interface between the active layer 12 and the buffer layer 13 is removed by the etching. A p-electrode 16 is attached to the doughnut shaped recess part 21. In this structure, a current is made to flow only through the active layer 12 at the remaining part, which is surrounded by the doughnut shaped recess part 21. Therefore, a current is made to flow only through the buffer layer 13, which remains at the center of the doughnut shaped recess part 21. Light emitting efficiency is high. A light emitting area is small. Therefore, coupling efficiency with optical fiber becomes high. |
