Gallium nitride-based semiconductor laser diode

A gallium nitride-based semiconductor laser diode comprising:

• a support base of a III-nitride semiconductor, the support base having a semipolar primary surface, the semipolar primary surface tilting at an angle ALPHA with respect to a first reference plane, the first reference plane being perpendicular to a reference axis, the reference axis extending in a direction of a c-axis of the III-nitride semiconductor;
• a first epitaxial semiconductor region comprising a first cladding layer and provided on the semipolar primary surface of the support base;
• a second epitaxial semiconductor region comprising a second cladding layer and provided on the semipolar primary surface of the support base;
• and
• a core semiconductor region provided on the semipolar primary surface of the support base,
• the core semiconductor region comprising a first optical guide layer, an active layer and a second optical guide layer,
• the active layer comprising an InX0Ga1-X0N layer,
• the active layer being provided so as to emit light at a lasing wavelength of not less than 500 nm,
• the first cladding layer comprising a gallium nitride-based semiconductor different from the III-nitride semiconductor, and material of the gallium nitride-based semiconductor being at least one of AlGaN and InAlGaN,
• the first epitaxial semiconductor region, the core semiconductor region and the second epitaxial semiconductor region being arranged in order in a direction of a normal axis normal to the semipolar primary surface of the support base,
• the c-axis being directed in a direction of either of <0001>axis and <000-1>axis,
• the angle ALPHA being in a range of not less than 10 degrees and less than 80 degrees,
• a thickness of the first epitaxial semiconductor region being larger than a thickness of the core semiconductor region,
• a density of misfit dislocations at an interface between the support base and the first epitaxial semiconductor region being not more than 1×106 cm−1,
• a density of misfit dislocations at an interface between the first epitaxial semiconductor region and the core semiconductor region being not more than 1×106 cm−1,
• a density of misfit dislocations at an interface between the core semiconductor region and the second epitaxial semiconductor region being not more than 1×106 cm−1,
• a conductivity type of the first cladding layer being opposite to that of the second cladding layer,
• the first optical guide layer being provided between the active layer and the first epitaxial semiconductor region,
• the first optical guide layer comprising a first InX1Ga1-X1N layer and a first GaN layer,
• the second optical guide layer being provided between the active layer and the second epitaxial semiconductor region, and
• the second optical guide layer comprising a second InX2Ga1-X2N layer and a second GaN layer,
• wherein a direction of the c-axis of the III-nitride semiconductor and a magnitude of a lattice constant d0 thereof in the direction of the c-axis are represented by a lattice vector LVC0,
• wherein a direction of a c-axis of a semiconductor material of the first cladding layer in the first epitaxial semiconductor region and a magnitude of a lattice constant d1 thereof in the direction of the c-axis are represented by a lattice vector LVC1,
• wherein the lattice vector LVC0 is constituted by a longitudinal component V0L in the direction of the normal axis and a transverse component V0T perpendicular to the longitudinal component,
• wherein the lattice vector LVC1 is constituted by a longitudinal component V1L in the direction of the normal axis and a transverse component V1T perpendicular to the longitudinal component, and
• wherein a lattice mismatch degree (V1T−V0T)/V0T in the transverse direction satisfies a lattice matching condition.