Semiconductor laser device
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorAkira Takemoto
Life of this patent
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Abstract
A semiconductor laser device of the buried heterostructure type in which leakage current is substantially reduced. A mesa portion carries the active lasing portion of the laser, and current blocking layers are grown at either side of the mesa portion. One of the current blocking layers has its conductivity type inverted to the opposite type to eliminate a current leakage path, thereby to provide a high efficiency low leakage current semiconductor laser. Conductivity inversion is accomplished by adjusting the impurity concentration levels in the layers on either side of the mesa portion, and controllably diffusing impurities from one layer to another until conductivity inversion is accomplished in a thin tip portion of one of the layers.
Claims7
A semiconductor laser device comprising:
- a first conductivity type semiconductor substrate;
- a mesa portion on the substrate including an active layer and a second conductivity type first cladding layer;
- successively grown impurity carrying layers on the substrate at both sides of the mesa portion including a first conductivity type embedded layer, a second conductivity type first current blocking layer, and a first conductivity type second current blocking layer;
- a second conductivity type second cladding layer disposed on the second current blocking layer and the first cladding layer;
- and
- the first current blocking layer having a tip portion adjacent tee mesa portion inverted from the second to the first conductivity type, thereby to minimize current leakage through said semiconductor laser device.
Dependencies are inferred from the claim text.