Method of fabricating group-iii nitride semiconductor laser device

A method for fabricating a III-nitride semiconductor laser device, comprising the steps of:

• forming a substrate product having a laser structure, the laser structure including a substrate and a semiconductor region, the substrate comprising a hexagonal III-nitride semiconductor and having a semipolar primary surface, and the semiconductor region being formed on the semipolar primary surface;
• scribing a first surface of the substrate product to form a scribed mark on the first surface, the scribed mark extending along a reference line indicative of a direction of an a-axis of the hexagonal III-nitride semiconductor;
• mounting the substrate product on a breaking device such that first and second support portions of the breaking device support first and second regions of the substrate product, respectively, after forming the scribed mark;
• and
• carrying out breakup of the substrate product by press in alignment with the scribed mark in a third region of the substrate product, without supporting the third region, to form another substrate product and a laser bar, the third region being located between the first and second regions,
• the third region of the substrate product being adjacent to the first and second regions,
• the press being implemented against a second surface of the substrate product,
• a first edge of the first support portion being separated from a second edge of the second support portion,
• the substrate product being mounted on the breaking device so that the reference line is apart from a center line defining a center between the first edge and the second edge,
• the first surface being a surface opposite to the second surface,
• the semiconductor region being located between the first surface and the substrate,
• the laser bar has first and second end faces extending from the first surface to the second surface and being made by the breakup,
• the first and second end faces forming a laser cavity of the III-nitride semiconductor laser device,
• the substrate product comprising an anode electrode and a cathode electrode provided on the laser structure,
• the semiconductor region including a first cladding layer, a second cladding layer, and an active layer provided between the first cladding layer and the second cladding layer, the first cladding layer comprising a first conductivity type GaN-based semiconductor, and the second cladding layer comprising a second conductivity type GaN-based semiconductor,
• the first cladding layer, the second cladding layer, and the active layer being arranged along a normal axis normal to the semipolar primary surface,
• a c-axis of the hexagonal III-nitride semiconductor of the substrate being inclined at an angle ALPHA with respect to an axis normal to the semipolar primary surface toward an m-axis of the hexagonal III-nitride semiconductor, and
• the first and second end faces intersecting with an m-n plane defined by the m-axis of the hexagonal III-nitride semiconductor and the normal axis normal to the semipolar primary surface.