| 摘要 |
PURPOSE:To provide excellent characteristics such as high oscillation efficiency, high light emitting efficiency, low threshold value current density by forming a projection region on the semiconductor layer on an active layer and forming a high resistance cadmium sulfide layer adjacent to the region, thereby forming a current narrowing mechanism. CONSTITUTION:A mask is formed on the uppermost InGaAsP layer 24, a P type InP layer 23 is allowed to remain at the side of a mesa 28, a high resistance sulfided cadmium 25 is formed on the layer 23 to cover the mesa 28. An Au-Ge 26 and an Au-Zn 27 electrode are formed, a resonator surface is formed by cleavage, thereby forming an element. The specific resistance of the sulfided cadmium is 10<5>-10<10>OMEGA-cm, and the layer 23 at the side of the mesa is extremely thin. Accordingly, almost no current flows except the mesa region 28. Thus, the bondability of the layers 23, 24 is improved, the manufacture in the element can be facilitated, and the reliability of the element can be enhanced. Since a 4-layer waveguide structure of cadmium sulfide, InP, InGaAsP and InP is formed outside the mesa, a difference occurs in the effective refractive index between the mesa and the outside the mesa, the light is enclosed in the mesa 28, thereby enabling to control the lateral oscillation mode. |
