| 摘要 |
PURPOSE:To obtain a semiconductor laser with small vertical radiation angle and low threshold current, by arranging an active layer with a specified refractive index. which is formed with alternately laminated quantum well layers having small forbidden band width and barrier layers having large forbidden band width, between two clad layers with larger forbidden band width and a smaller refractive index than those of the active layer. CONSTITUTION:A first, conductive type clad layer 2, a super lattice structure active layer 3, a second conductive type clad layer 4, and a second, conductive type contact layer 5 are epitxially grown in order, and a stripe-form P type ohmic electrode 6 which elongates toward the radiating direction of the laser light is provided on the layer 5, and a N type ohmic electrode 7 is provided on the whole surface of the base board side 1. The active layer 3 has super lattice structure in which well layers 8 and barrier layer 9 with forbidden band width larger than that of the layer 8 are laminated. The clad layers 2 and 4 have larger forbidden band width and smaller refractive index than that of the active layer 3. Giving the active layer 3 a super lattice structure decreases the difference between the refractive indexes of the clad layers 2 and 4 without decreasing the difference of the forbidden band width between them, allowing the decrease in the oscillation threshold and vertical direction radiation angle.
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