Semiconductor laser with mesa stripe waveguide structure and manufacturing method thereof

Claim 1

A semiconductor laser (10) for emitting a continuous laser light of visible wavelength range comprising a semiconductor substrate (12) of a first conductivity type made of III-V compound semiconductor material, a first semiconductor cladding layer (18) of the first conductivity type provided above said substrate (12), an active layer (20) of semiconductor material formed on said cladding layer (18), and a plurality of semiconductor cladding layers of a second conductivity type formed on said active layer (20), thereby forming a double hetero- structure, characterized in that said cladding layer includes a second semiconductor cladding layer (22) formed directly on said active layer (20), and a third semiconductor cladding layer (26) which is formed on said second cladding layer (22) and is mesa-shaped to have slanted sides (26a, 26b) defining a waveguide channel, said first to third cladding layers (18, 22, 26) being made of compound semiconductor material comprising III-elements and V-elements, and that said laser (10) further comprises: a first semiconductive contact layer (30) of the second conductivity type formed on said third cladding layer (26), being mesa-shaped, and having slanted sides; and a semiconductive, current-blocking layer (34-1, 34-2) covering the slanted sides (26a, 26b) of said third cladding layer (26) and also the slanted sides of said first contact layer (30), said current-blocking layer (34-1, 34-2) being made of III-V compound semiconductor material which is substantially the same as the III-V compound semiconductor material of said substrate (12).

Claim 19

A method of manufacturing a semiconductor laser for emitting a continuous laser beam of visible wavelength range, characterized by comprising the steps of: forming a double hetero-structure on a semiconductor substrate (12) of a first conductivity type made of a III-V compound semiconductor material by means of metal organic chemical vapor deposition, said double hetero-structure comprising a first semiconductive cladding layer (18) of the first conductivity type, an active layer (20) of semiconductor material formed on said first cladding layer, a second semiconductive cladding layer (22) of a second conductivity type formed on said active layer, and a third semiconductive cladding layer (26) of the second conductivity type formed on said second cladding layer and made of compound semiconductor material comprising a plurality of III-elements and one V-element; forming a first semiconductive contact layer (32) of the second conductivity type on said double hetero-structure; forming an insulative layer (40) on said first contact layer; applying selective etching to said first contact layer (32) by using said insulative layer (40) as a mask, thereby forming a mesa-shaped layer (32') having a flat top surface and slanted sides; applying selective etching to said third cladding layer (26) by using said mesa-shaped layer (32') as a mask, thereby forming a waveguide channel and also a mesa-shaped layer (26') having a flat top surface and slanted sides; and forming a semiconductive, current-blocking layer (34, 62) of the first conductivity type on the resultant structure, said current-blocking layer (34, 62) covering the slanted sides of said third cladding layer and also the slanted sides of said first contact layer and being made of substantially the same III-V compound semiconductor as said substrate.

Claim 20

A method of manufacturing a semiconductor laser for emitting a continuous laser beam of visible wavelength range, characterized by comprising the steps of: forming a double hetero-structure on a semiconductor substrate (12) of a first conductivity type made of a III-V compound semiconductor material by means of metal organic chemical vapor deposition, said double hetero-structure comprising a first semiconductive cladding layer (18) of the first conductivity type, an active layer (20) of semiconductor material formed on said first cladding layer, a second semiconductive cladding layer (22) of a second conductivity type formed on said active layer, and a third semiconductive cladding layer (26) of the second conductivity type formed on said second cladding layer and made of compound semiconductor material comprising a plurality of III-elements and one V-element; forming a first semiconductive contact layer (32) of the second conductivity type on said double hetero-structure; forming an insulative layer (40) on said first contact layer; applying selective etching to said first contact layer (32) by using said insulative layer (40) as a mask, thereby forming a mesa-shaped layer (32') having a flat top surface and slanted sides; applying selective etching to said third cladding layer (26) by using said mesa-shaped layer (32') as a mask, thereby forming a waveguide channel and also a mesa-shaped layer (26') having a flat top surface and slanted sides; and forming a semiconductive, current-blocking layer (34, 62) of the first conductivity type on the resultant structure, said current-blocking layer (34, 62) covering the slanted sides of said third cladding layer and also the slanted sides of said first contact layer and being made of substantially the same III-V compound semiconductor as said substrate.