Semiconductor laser device and manufacturing method therefor

A method for manufacturing a semiconductor laser device, comprising:

• forming on a semiconductor substrate a first clad layer, an active layer, a second clad layer one on another in that order;
• forming a ridge portion in the second clad layer;
• forming a current constriction layer on the second clad layer and on both sides of the ridge portion;
• forming a flattening layer on the ridge portion of the second clad layer and on the current constriction layer by a liquid phase epitaxial process;
• and
• forming a contact layer on the flattening layer by a vapor phase epitaxial process.

A method for manufacturing a semiconductor laser device, comprising:

• forming a first clad layer, an active layer, a lower-side second clad layer and a current constriction layer on a semiconductor substrate;
• forming a striped groove in the current constriction layer;
• forming an upper-side second clad layer on the lower-side second clad layer and on the current constriction layer by a temperature-difference liquid phase epitaxial process;
• and
• forming a contact layer on the upper-side second clad layer by a temperature-difference liquid phaseepitaxial process.