Kabushiki Kaisha Toshiba

Shigeya Naritsuka

Masayuki Ishikawa

Yoshihiro Kokubun

Kazuhiko Itaya

Genichi Hatakoshi

Hideto Sugawara

Yasuo Ohba

Yukie Nishikawa

Yukio Watanabe

Hideo Shiozawa

Hajime Okuda

Yutaka Uematsu

Mariko Suzuki

Disclosed is a semiconductor light emitting device, comprising a semiconductor substrate, a double hetero structure portion formed on the front surface of the substrate and consisting of an InGaAlP active layer and lower and upper clad layers having the active layer sandwiched therebetween, a first electrode formed in a part of the surface of the double hetero structure portion, and a second electrode formed on the back surface of the substrate. A current diffusion layer formed of GaAlAs is interposed between the double hetero structure portion and the first electrode, said current diffusion layer having a thickness of 5 to 30 microns and a carrier concentration of 5.times.10.sup.17 cm.sup.-3 to 5.times.10.sup.18 cm.sup.-3.

Semiconductor light emitting device

A semiconductor light emitting device, especially, a light emitting diode includes a compound semiconductor substrate of a first conductivity type, an InGaAlP layer formed on the substrate and having a light emitting region, a GaAlAs layer of a second conductivity type formed on the InGaAlP layer and having a larger band gap than that of the InGaAlP layer, and an electrode formed on a part of the GaAlAs layer. The light emitting diode emits light from a surface at the electrode side except for the electrode. A current from the electrode is widely spread by the GaAlAs layer to widely spread a light emitting region.

In a semiconductor laser device, for emitting a laser beam having a wavelength .lambda., an n-type In.sub.0.5 (Ga.sub.1-x Al.sub.x)P first cladding layer is formed on an n-type GaAs substrate. An undoped InGaP active layer is formed on the first cladding layer and a p-type In.sub.0.5 (Ga.sub.1-x Al.sub.x).sub.0.5 P cladding layer is formed on the active layer. A p-type InGaP cap layer is formed on the second cladding layer and an n-type GaAs current restricting layer is formed on the second cladding layer. The aluminum composition ratio x of the cladding layer is 0.7. The active layer has a thickness of 0.06 .mu.m and the cladding layers have the same thickness H of 0.85 .mu.m. The active layer and the cladding layers have refractive indices n.sub.a and n.sub.c which satisfies the following inequalities:

Semiconductor laser device

Semiconductor laser device which has a double-hetero structure having an

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Yokohama, Japan

Shigeya Naritsuka