Semiconductor laser device and manufacturing method thereof

A semiconductor laser device comprising, in this order:

• a cladding layer of a first conductivity type;
• an active layer;
• a cladding layer of a second conductivity type opposite that of said first conductivity type;
• a low resistivity layer doped with an impurity of the first conductivity type, having a striped opening with a specific width and having a smaller refractive index than that of said second conductivity type cladding layer and a bandgap energy greater than energy of lasing light, and
• a current blocking layer of the first conductivity type formed on said low resistivity layer and having a greater thermal conductivity than said low resistivity layer,
• wherein said low resistivity layer has an impurity concentration of 5.times.10.sup.7 cm.sup.-3 or less at least in the region on said active layer side in the thickness direction, and
• wherein said low resistivity layer has a thickness of at least 0.3 .mu.m and not greater than 1 .mu.m.

A semiconductor laser device comprising, in this order:

• a cladding layer of a first conductivity type;
• an active layer;
• a cladding layer of a second conductivity type opposite that of said first conductivity type;
• a low resistivity layer doped with an impurity of the first conductivity type, having a striped opening with a specific width and having a smaller refractive index than that of said second conductivity type cladding layer and a bandgap energy greater than energy of lasing light, and
• a current blocking layer of the first conductivity type formed on said low resistivity layer and having an impurity concentration greater than said low resistivity layer,
• wherein said low resistivity layer has an impurity concentration of 5.times.10.sup.17 cm.sup.-3 or less at least in the region on said active layer side in the thickness direction, and wherein said low resistivity layer has a thickness of at least 0.3 .mu.m and not greater than 1 .mu.m.

A semiconductor laser device comprising, in this order:

• a cladding layer of a first conductivity type;
• an active layer;
• a cladding layer of a second conductivity type opposite that of said first conductivity type;
• and
• a low resistivity layer doped with an impurity of the first conductivity type, having a striped opening with a specific width and having a smaller refractive index than that of said second conductivity type cladding layer and a bandgap energy greater than energy of lasing light,
• wherein said low resistivity layer has an impurity concentration of 5.times.10.sup.17 cm.sup.-3 or less at least in the region on said active layer side in the thickness direction,
• wherein said low resistivity layer has a thickness of at least 0.3 .mu.m and not greater than 1 .mu.m,
• wherein said second conductivity type cladding layer includes a flat portion formed on said active layer and a striped ridge portion formed on said flat portion,
• wherein said low resistivity layer is formed on the upper surface of said flat portion and side surfaces of said ridge portion, and
• wherein said semiconductor laser device further comprising an etching stopping layer provided on said flat portion and between said flat portion and said ridge portion.