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US 6,603,147 B1Granted
Semiconductor light emitting device
AssigneeSony Corporation
InventorsShigeki Hashimoto, Katsunori Yanashima, Masao Ikeda, Hiroshi Nakajima
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AssigneeSony Corporation
InventorsShigeki Hashimoto, Katsunori Yanashima, Masao Ikeda, Hiroshi Nakajima
Estimating the term…
A semiconductor light emitting device using nitride III-V compound semiconductors is improved to reduce the threshold current density with almost no increase of the operation voltage. In a GaN semiconductor laser as one version thereof, the p-type cladding layer is made of two or more semiconductor layers different in band gap, and a part of the p-type cladding layer near one of its boundaries nearer to the active layer is made of a semiconductor layer having a large band gap than that of the remainder part. More specifically, in a AlGaN/GaN/GaInN SCH-structured GaN semiconductor laser, a p-type AlGaN cladding layer is made of a p-type Alx1Ga1−x1N layer in contact with a p-type GaN optical guide layer, and a p-type Alx2Ga1−x2N layer overlying the p-type Alx1Ga1−x1N layer (where 0≦x2<x1≦1).
A semiconductor light emitting device having a structure in which an active layer is sandwiched between an n-type cladding layer and a p-type semiconductor layer, said active layer, said n-type cladding layer and said p-type semiconductor layer being made of nitride III-V compound semiconductor, said p-type semiconductor layer comprising at least a p-type AlGaN layer, an optical guide layer and a third p-type semiconductor layer, said third p-type semiconductor layer being a p-type cladding layer comprising at least a first and a second p-type semiconductor coating layer whereby the first p-type semiconductor coating layer nearer to said active layer being made of a semiconductor layer material having a larger band gap than that of the second p-type semiconductor coating layer, and the optical guide layer and the second p-type semiconductor coating layer being different in band gap from each other;
Dependencies are inferred from the claim text.