| 摘要 |
PURPOSE:To raise the cut-off frequency in a light-emitting diode having a structure in which an active layer continuously extends over not only an active region for passing current but also a region surrounding the active region, by making the thickness of the peripheral portion of the active region smaller than the thickness of the central portion of the active region. CONSTITUTION:When an active region for passing current is provided in the central portion of the surface of a P type GaAs substrate 1, a groove 8B is formed in the area for forming the active region. A current constriction layer 2 is formed on the surface of the substrate 1 so as to surround the groove 8B. A P type AlGaAs lower clad layer 3 is deposited all over the layer 2 and the bottom of the groove 8B. A P type GaAs active layer 4B is deposited on the whole surface so that the thickness of the peripheral portion of the active region located in the groove 8B is smaller than that of the central portion of the active region. The whole surface is covered with an N type AlGaAs upper clad layer 5, and an annular ohmic electrode 6 is attached to the outer peripheral portion of the layer 5, while an ohmic electrode 7 is deposited all over the reverse surface of the substrate 11. In this way, the carrier density of the peripheral portion of the groove 8B is increased to prevent lowering of the cut-off frequency. |
