Patent ID: 8175129

Claim:
A group-III nitride semiconductor laser device comprising: a laser structure including a support base and a semiconductor region, the support base comprising a hexagonal group-III nitride semiconductor and having a semipolar principal surface, the semiconductor region being provided on the semipolar principal surface of the support base; and an electrode being provided on the semiconductor region of the laser structure, wherein an angle between the normal axis and a c-axis of the hexagonal group-III nitride semiconductor is in a range of not less than 45° and not more than 80° or in a range of not less than 100° and not more than 135°, wherein the semiconductor region includes a first cladding layer comprising a first conductivity type gallium nitride (GaN)-based semiconductor, a second cladding layer comprising a second conductivity type GaN-based semiconductor, and an active layer being provided between the first cladding layer and the second cladding layer, wherein the first cladding layer, the second cladding layer, and the active layer are arranged along the normal axis to the semipolar principal surface, wherein the active layer includes a GaN-based semiconductor layer, wherein the c-axis of the hexagonal group-III nitride semiconductor of the support base tilts at an angle ALPHA with respect to the normal axis toward an m-axis of the hexagonal group-III nitride semiconductor, wherein the laser structure includes first and second fractured faces intersecting with an m-n plane defined by the m-axis of the hexagonal group-III nitride semiconductor and the normal axis, wherein a laser cavity of the group-III nitride semiconductor laser device includes the first and second fractured faces, wherein each of the first and second fractured faces extends from an edge of the first surface to an edge of the second surface, wherein the laser structure includes first and second surfaces, and the first surface is a surface opposite to the second surface, wherein the semiconductor region is located between the first surface and the substrate, wherein the laser structure includes a laser stripe extending in a direction of a waveguide axis above the semipolar principal surface of the support base, and the waveguide axis extends from one to the other of the first and second fractured faces, wherein the laser structure has first and second recesses provided each at a portion of the edge of the first surface in the first fractured face, the first and second recesses extend from the first surface of the laser structure, and bottom ends of the first and second recesses are located apart from the edge of the second surface of the laser structure, wherein the first recess has an end at the first surface, and the second recess has an end at the first surface, and wherein a first distance between the laser stripe and the end of the first recess is smaller than a second distance between the laser stripe and the end of the second recess.