| 摘要 |
PURPOSE:To enable to bring the tip end of a diffusion region to come to the desired position by a method wherein the surface layer only is selectively heated up and maintained at the temperature higher than that of the other semiconductor layer when diffusion is performed on the crystal which is formed in multilayer construction. CONSTITUTION:A Te-added N type InP clad layer 15, an undoped InGaAsP active layer 16, a Zn-added P type InP clad layer 17, and an 8n or Te added InGaAsP cap layer 18 are laminated successively on an N type InP substrate 14. Then, a diffusion mask 19 of SiO2 is provided on the cap layer 18, and impurities are diffused on the crystal 20. In this case, when an Nd-added YAG layer beam 23 is irradiated on the surface of the InGaAsP cap layer 18 of the crystal 20, said laser beam 23 is absorbed by the cap layer 18 alone and selectively heated up. Accordingly, the point of a Zn diffusion region 25 is positioned at the boundary of the cap layer 18 and the P type InP clad layer 17. Then, the SiO2 diffusion mask 19 is removed by etching, and a P type ohmic electrode of Au-Zn is formed on the cap layer 18. Subsequently an Au-Ge N type ohmic electrode is formed on the surface of the N type InP substrate. Then, Cr and Au are vapor-deposited, and after a P type electrode 26 and an N type electrode 27 have been formed, they are formed into chips, thereby enabling to obtain a semiconductor laser. |
