Semiconductor laser device and method of manufacturing the same

A semiconductor laser device comprising:

• a GaN substrate;
• a semiconductor layer formed on a top surface of the GaN substrate;
• a ridge formed at a top of the semiconductor layer;
• a recess formed in a bottom surface of the GaN substrate, the recess having a depth less than a thickness of the GaN substrate;
• a notch formed on a side surface of the GaN substrate intersecting with a direction of extension of the ridge and being separated from the recess by the GaN substrate, the notch being deeper than the recess;
• a first electrode formed on a top surface of the ridge;
• and
• a second electrode formed on a bottom surface of the recess, wherein
• a total thickness of the GaN substrate and the semiconductor layer is 100 μm or more, and
• a first distance is 5 μm or more and 50 μm or less, the first distance is a distance between the top surface of the ridge and the bottom surface of the recess.