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US 6,738,405 B1Granted
Semiconductor laser
AssigneeFurukawa Electric Co., Ltd.
InventorsTakeharu Yamaguchi, Toshikazu Mukaihara, Akihiko Kasukawa
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AssigneeFurukawa Electric Co., Ltd.
InventorsTakeharu Yamaguchi, Toshikazu Mukaihara, Akihiko Kasukawa
Estimating the term…
A semiconductor laser device (30) includes a layered structure formed on an n-type GaAs substrate (32) having a bandgap energy Eg1 and including an n-type AlGaAs cladding layer (34), an active layer (36) including a quantum-well structure of two layers InGaAs/GaAs having a bandgap energy Eg2 which is smaller than Eg1, a p-type AlGaAs cladding layer (38), and a p-type GaAs cap layer (40), which are consecutively epitaxially grown. The cap layer and the upper portion of the p-type cladding layer are formed as a stripe-shaped mesa structure. An SiN passivation film (42) is formed on the areas except for the top of the cap layer. On the exposed cap layer and the passivation layer a p-side electrode (44) is formed. On the bottom surface of the substrate an n-side electrode (46) including layered metal films of In/AuGe/Ni/Au is formed. An absorption medium layer is interposed between the GaAs substrate and the n-side electrode.
A semiconductor laser device comprising an active layer having a bandgap energy Eg2 and epitaxially grown on a semiconductor substrate having a bandgap energy Eg1, wherein Eg1>Eg2, characterized in that an absorption medium layer for absorbing laser light emitted by the active layer is formed on a bottom surface of the semiconductor substrate, wherein the absorption medium layer is formed by an alloying reaction between a metal electrode layer formed on the bottom surface of the substrate and the semiconductor substrate.
Dependencies are inferred from the claim text.