ELECTRODE STRUCTURE OF SEMICONDUCTOR LASER DIODE

PURPOSE:To prevent solder or electrode metal from diffusing or reacting to alloy into semiconductor by bonding a solder blocking layer on the end of a main surface of a semiconductor crystal. CONSTITUTION:A clad layer 2, an active layer 3, a clad layer 4, a surface layer 5, a moire p type GaAs layer 6 and electrodes 9 are formed on a substrate 1, an Si3N4 film 15 is superposed, and a window 16 is opened. A distance l from the cleaved surface 11 of a chip to the window 16 remains. A Cr film 17 and an Mo film 18 are superposed on the overall surface, and Au film 19 is coated within a distance (d) from the end. After dividing, the end 11 is coated by a protective film 12, and a chip 21 is completed. With the film 19 disposed underlayer as a submount 13, AuSn solder 14 is connected. l is approx. 10mum, d is approx. 5mum. With this construction, the semiconductor crystal near the end 22 of the reflecting surface 11 which becomes the highest temperature during operation does not contact via the film 15 directly with metals 17-19 or the solder 14, and the diffusion or alloying reaction of the metal and solder with the Si3N4 can be blocked. When BeO is used for the solder, thermal diffusion can be sufficiently performed, excess temperature rise of the end of the chip can be prevented to prevent the characteristic from deteriorating.