Method for manufacturing semiconductor laser device

A method for manufacturing a semiconductor laser device comprising:

• first step of sequentially laminating on a semiconductor substrate of a first conductivity type, a first clad layer of a first conductivity type, an active layer, a first second clad layer of a second conductivity type, a semiconductor layer of the second conductivity type with an index of refraction different from the index of refraction of the second clad layer, and a second second clad layer of the second conductivity type;
• second step of forming a first insulating film of a Si-based substance on the surface of the second second clad layer, and forming with the first insulating film a first insulating film pattern with a plurality of first openings which have a strip shape of a predetermined length in the direction intersecting the direction of an optical wave guide, and which are arranged at intervals of a predetermined distance in the direction of an optical wave guide;
• third step of forming a second insulating film of a Si-based substance over the semiconductor substrate through the first insulating film pattern, and forming with the second insulating film through the first insulating film pattern a second insulating film pattern with a second opening which has a strip shape extending in the direction of the optical wave guide, and which has a width narrower than the length of the first opening in the direction intersecting the optical wave guide direction;
• fourth step of etching the second second clad layer and the semiconductor layer using the second insulating film pattern and the first insulating film pattern as masks to form a third opening passing through the semiconductor layer;
• and
• fifth step of removing the second insulating film pattern and the first insulating film pattern, and filling the second second clad layer and the semiconductor layer through the third opening with a third second clad layer of the second conductivity type.