Method for manufacturing semiconductor laser device, and semiconductor laser device

A method for manufacturing a semiconductor laser device comprising the steps of:

• a ridge forming step in which a laminated structure is formed by laminating a cladding layer of a first conductivity type, an active layer, a first cladding layer of a second conductivity type opposite to the first conductivity type, and a cap layer made of a semiconductor material different from the second conductivity type first cladding layer in order in a vertical direction on a surface of a substrate of the first conductivity type, and a first side area and a second side area of the laminated structure are etched to a position closer to the substrate than the active layer to form a ridge having a first side and a second side;
• a ridge burying step in which a first buried layer of a conductivity type different from the first conductivity type is buried in both the first side and the second side of the ridge to a position higher than the first cladding layer;
• a second buried layer forming step in which a second buried layer of the first conductivity type is grown so as to cover the ridge and the first buried layer, and directly contact the cap layer;
• a cap layer exposing step in which the second buried layer at a position corresponding to a center of the ridge is etched to expose the cap layer at the center of the ridge;
• a first cladding layer exposing step in which the cap layer exposed at the center of the ridge is etched to expose the first cladding layer;
• and
• a second cladding layer forming step in which a second cladding layer of the second conductivity type is grown so as to be buried on the second buried layer, the first cladding layer exposed at the center of the ridge and an exposed side face of the cap layer located between the second buried layer and the first cladding layer, wherein
• the cap layer is positioned between the first cladding layer and the second buried layer in the vertical direction.