| 摘要 |
PURPOSE: To improve the characteristic, by placing an intermediate layer between a conductive layer and a second clad layer so as to form a barrier together with the conductive layer, and employing a semiconductor material of a second conduction type whose band gap is between a band gap of the second clad layer and that of a contact layer for the intermediate layer. CONSTITUTION: An intermediate layer 5 is placed between a conductive layer 7 and a second clad layer 4 so as to form a junction to form a barrier together with the conductive layer and a semiconductor material of a second conduction type whose band gap is between a band gap of the second clad layer 4, and that of a contact layer 6 is adopted for the intermediate layer 5. Since the intermediate layer 5 is apart more from an active layer 3 than the clad layer 4, even when doping of the intermediate layer 5 is selected with a higher concentration, a danger of a pn-junction apart from the active layer 3 is kept less. Furthermore, the intermediate layer 5 has a doping gradient higher at the side of the clad layer and lower at the contact layer. Thus, the doping with the lower gradient forms a barrier between the intermediate layer 5 and the conductor layer 7 more effectively to improve a current limit performance and the doping with the higher gradient improves a current - voltage characteristic. |
