Semiconductor laser and method for producing the same

A semiconductor laser comprising:

• a semiconductor substrate of a first conductivity type;
• a stripe-shaped multilayer structure, formed on the semiconductor substrate, the stripe-shaped multilayer structure including an active layer;
• and
• a current blocking portion formed on the semiconductor substrate on both sides of the stripe-shaped multilayer structure,
• wherein the current blocking portion has a first current blocking layer of a second conductivity type, and a second current blocking layer of the first conductivity type formed on the first current blocking layer, and
• one of two end portions of the second current blocking layer which is closer to the stripe-shaped multilayer structure has an apex angle 60 degrees or more.

A semiconductor laser comprising:

• a semiconductor substrate of a first conductivity type;
• a stripe-shaped multilayer structure including a quantum well type active layer having a graded doped structure formed on the semiconductor substrate;
• a current blocking portion formed on both sides of the stripe-shaped multilayer structure, for confining a current in the stripe-shaped multilayer structure;
• and
• a semiconductor layer of a second conductivity type formed above the stripe-shaped multilayer structure and the current blocking portion,
• wherein the semiconductor laser further includes a diffusion suppressing layer covering both the stripe-shaped multilayer structure and the current blocking portion for suppressing an impurity included in the semiconductor layer of the second conductivity type from diffusing into the active layer, the diffusion suppressing layer having a bandgap which is smaller than that of the current blocking portion.