Optical semiconductor device and semiconductor light-emitting device

A semiconductor light-emitting device comprising:

• an optical semiconductor device, comprising:
• a semiconductor substrate with a protrusion,
• wherein the protrusion forms a lower end portion of a mesa stripe structure in a stripe shape extending in a first direction along an optical axis;
• a multi-quantum well layer in a stripe shape extending in the first direction on the protrusion,
• wherein the multi-quantum well layer forms an intermediate portion of the mesa stripe structure;
• a semiconductor layer in a stripe shape extending in the first direction on the intermediate portion,
• wherein the semiconductor layer forms an upper end portion of the mesa stripe structure;
• a semi-insulating semiconductor layer in contact with side surfaces of the mesa stripe structure on both sides in a second direction perpendicular to the first direction;
• a first electrode on a surface, opposite the protrusion, of the semiconductor substrate;
• a second electrode including a mesa electrode on the upper end portion of the mesa stripe structure,
• wherein the second electrode includes a lead-out electrode extending in the second direction from the mesa electrode,
• wherein the second electrode includes a pad electrode connected to the lead-out electrode;
• and
• a metal film including a first portion positioned on both sides of the lead-out electrode in the first direction and on an upper surface of the semiconductor substrate next to the protrusion in the second direction and not covered by the semi-insulating semiconductor layer,
• wherein the first portion is positioned adjacent to the lead-out electrode and between the pad electrode and the mesa electrode, and
• wherein the metal film includes a second portion positioned next to and not contracting the pad electrode and continuously integrated with at least part of the first portion;
• and
• a carrier on which the optical semiconductor device is mounted.