Buried stripe type semiconductor laser device

A semiconductor laser device comprising:

• a semiconductor substrate of a first conductivity type having a main surface with a (100) crystal orientation;
• a mesa stripe formed in said main surface of said semiconductor substrate, said mesa stripe being oriented along the <011>
• direction and having a top surface with a (100) crystal orientation, said mesa stripe being formed by a portion of said semiconductor substrate;
• a multilayer structure formed on said top surface of said mesa stripe, said multilayer structure including an active layer for a laser oscillation, side faces of said multilayer structure being {111} facets;
• at least one semiconductor layer which covers said multilayer structure, a top surface of said semiconductor layer having a raised portion above said multilayer structure;
• and
• current confinement means for confining electric currents within said mesa stripe, said current confinement means including an additional semiconductor layer formed on said at least one semiconductor layer, said additional semiconductor layer locating above regions of said main surface of said semiconductor substrate where said mesa stripe is not formed.

A semiconductor laser device comprising:

• a semiconductor substrate of a first conductivity type having a main surface with a (100) crystal orientation;
• a mesa stripe formed in said main surface of said semiconductor substrate, said mesa stripe being oriented along the <011>
• direction and having a top surface with a (100) crystal orientation, said mesa stripe being formed by a portion of said semiconductor substrate;
• a multilayer structure formed on said top surface of said mesa stripe, said multilayer structure including an active layer for a laser oscillation, side faces of said multilayer structure being (111) facets;
• at least one semiconductor layer which covers said multilayer structure, a top surface of said semiconductor layer having a raised portion above said multilayer structure;
• and
• current confinement means for confining electric currents within said mesa stripe, said current confinement means including an additional semiconductor layer formed on said at least one semiconductor layer, said additional semiconductor layer being located above regions of said main surface of said semiconductor substrate where said mesa stripe is not formed, and
• wherein said device has a substantially flat top surface.