Patent ID: 7653114

Claim:
A semiconductor laser diode comprising: a semiconductor substrate of a first conductivity type; a multilayer semiconductor layer constituted of a first conductivity type clad layer of the first conductivity type, an active layer, a second conductivity type clad layer of a second conductivity type, and a contact layer of the second conductivity type sequentially stacked on a first plane of said semiconductor substrate; a plurality of partitioning grooves formed in said multilayer semiconductor layer, extending from one end to the other end of said semiconductor substrate, and formed from a surface of said contact layer to a predetermined depth of said second conductivity type clad layer; a stripe-shaped ridge formed in each partitioning region sandwiched between adjacent ones of said partitioning grooves, and sandwiched between two separation grooves extending from the one end to the other end of said semiconductor substrate and formed from the surface of said contact layer to the predetermined depth of said second conductivity type clad layer; an insulating layer covering an area from each side wall of said contact layer of each of said ridges to an edge of said partitioning grooves via said separation groove; a first electrode formed on a second plane opposite to the first plane of said semiconductor substrate; and a second electrode formed in each of said partitioning regions, covering an area above said ridge, above said separation grooves on both sides of said ridge and above said multilayer semiconductor layers outside said separation grooves, wherein: said second electrode is constituted of a lower second electrode layer and a second plated layer formed stacked upon said second electrode layer; and said second plated layer has an arc cross section that a region corresponding a portion of said ridge is thickest and the second plated layer becomes gradually thin toward said partitioning grooves.