Sharp Kabushiki Kaisha Corporation

501 Sharp Kabushiki Kaisha

Takahiro Suyama

Toshiro Hayakawa

Saburo Yamamoto

Masafumi Kondo

Kohsei Takahashi

Kosei Takahashi

Sadayoshi Matsui

Mitsuhiro Matsumoto

Hiroyuki Hosoba

Masahiro Hosoda

Toshio Hata

Kazuaki Sasaki

Seiki Yano

Nobuyuki Miyauchi

Atsuo Tsunoda

Taiji Morimoto

Akinori Seki

Masaki Kondo

Mototaka Taneya

Shinji Kaneiwa

Ken Ohbayashi

Masafumi Kondou

A semiconductor laser device includes: a semiconductor substrate of a first conductivity type; a layered structure including at least a first cladding layer of the first conductivity type, an active layer, and a second cladding layer of a second conductivity type. The layered structure is provided on the semiconductor substrate. The semiconductor laser device also includes: a current blocking structure, having a striped concave portion therein, formed on the layered structure; and a third cladding layer of the second conductivity type provided so as to cover the striped concave portion and the current blocking structure. The current blocking structure includes at least a saturable absorbing layer having a forbidden band width which is substantially equal to a forbidden band width of the active layer.

Semiconductor laser device and method for producing the same

The semiconductor laser device of the invention includes: an n-type semiconductor and a semiconductor multi-layer structure formed on the n-type semiconductor. The semiconductor multi-layer structure includes: an active layer; an n-type first cladding layer and a p-type second cladding layer which are disposed so as to sandwich the active layer therebetween; an n-type current/light confinement layer having a stripe-shaped groove portion for injecting a current into a selected region of the active layer; and a p-type third cladding layer formed so as to bury the stripe-shaped groove portion of the n-type current/light confinement layer. In the semiconductor laser device, the current/light confinement layer contains Si as a dopant and the n-type first cladding layer contains substantially no Si as a dopant.

Semiconductor laser device

An optical information reproduction apparatus includes a semiconductor laser device as a light source which provides oscillation as periodic pulse waves upon application of a DC current. The semiconductor laser device is disposed so that an optical distance L from a light-emitting point of the semiconductor laser device to a recording surface of an optical recording medium satisfies the following relationship: TP&lt;(4L/C) and T&gt;TP+(2L/C), where T is a period of pulse waves which are output from the semiconductor laser device in absence of a returning light from the optical recording medium; TP is a pulse width of the respective pulse waves which is defined as a width of a portion of the respective pulse waves, the portion having intensities which correspond to 10% or more of the peak intensity of the respective pulse waves; and C is a speed of light through air.

Optical information reproduction apparatus having a semiconductor laser

A method for growing a compound semiconductor layer of Al.sub.x Ga.sub.1-x As (0.ltoreq.x.ltoreq.1) on a compound semiconductor substrate uses a molecular beam epitaxial apparatus, the method including the steps of providing the substrate having a GaAs layer on an upper surface thereof, thermally etching the GaAs layer by heating the substrate at a temperature and irradiating the GaAs layer with a gallium molecular beam and an arsenic molecular beam to expose the upper surface of the substrate, and growing the Al.sub.x Ga.sub.1-x As (0.ltoreq.x.ltoreq.1) layer on the upper surface of the substrate.

Method for growing a compound semiconductor and a method for producing a

On a GaAs substrate (Al.sub.Y Ga.sub.1-Y).sub.0.5 In.sub.0.5 P crystal layers (0.ltoreq.Y.ltoreq.1) is formed to be lattice-matched with the substrate. By radiating As molecular beams on the surface of the crystal layers while heating the layered substrate to a temperature at which In in the crystal layers evaporates, the portion near the surface of the crystal layers is changed into an Al.sub.Y Ga.sub.1-Y As crystal layer (0.ltoreq.Y.ltoreq.1) of a thickness of several molecules, on which layer an Al.sub.X Ga.sub.1-X As crystal layer (0.ltoreq.X.ltoreq.1) is formed. Since the surface of the Al.sub.Y Ga.sub.1-Y As crystal layer has been purl fled, the formed Al.sub.X Ga.sub.1-X As crystal layer has a high crystallinity, allowing production of a light emitting diode, a semiconductor laser device and the like with high efficiency.

Semiconductor laser device, and a method for producing a compound

A semiconductor laser device which can effectively confine electrons and positive holes is disclosed. The semiconductor laser device includes a semiconductor substrate of a first conductivity type, a current blocking layer of a second conductivity type, a first semiconductor layer of the first conductivity type made of a III-V group compound semiconductor, an active layer made of a III-V group compound semiconductor, and a second semiconductor layer. The semiconductor substrate has a ridge-type mesa having (n11)A planes. The current blocking layer is formed on the semiconductor substrate other than the top face of the mesa. The first semiconductor layer is formed on the entire surface of the current blocking layer and on the top face of the mesa. The active layer is formed on the first semiconductor layer. The second semiconductor layer is formed on the active layer. The second semiconductor layer has inclined portions, and is made of a III-V group compound semiconductor containing an amphoteric element as an impurity so that the inclined portions are of the first conductivity type and the other portions are of the second conductivity type.

On a GaAs substrate (Al.sub.Y Ga.sub.1-Y).sub.0.5 In.sub.0.5 P crystal layers (0.ltoreq.Y.ltoreq.1) is formed to be lattice-matched with the substrate. By radiating As molecular beams on the surface of the crystal layers while heating the layered substrate to a temperature at which In in the crystal layers evaporates, the portion near the surface of the crystal layers is changed into an Al.sub.Y Ga.sub.1-Y As crystal layer (0.ltoreq.Y.ltoreq.1) of a thickness of several molecules, on which layer an Al.sub.X Ga.sub.1-X As crystal layer (0.ltoreq.X.ltoreq.1) is formed. Since the surface of the Al.sub.Y Ga.sub.1-Y As crystal layer has been purified, the formed Al.sub.X Ga.sub.1-X As crystal layer has a high crystallinity, allowing production of a light emitting diode, a semiconductor laser device and the like with high efficiency.

A semiconductor laser device is provided which includes a semiconductor substrate and a multi-layered structure disposed on the substrate, the multi-layered structure containing an Al.sub.x Ga.sub.1-x As (0&lt;x&lt;1) first cladding layer formed on the substrate, an Al.sub.y Ga.sub.1-y As (0&lt;y&lt;1, x&gt;y) active layer for laser oscillation formed on the first cladding layer, an Al.sub.x Ga.sub.1-x As (0&lt;x&lt;1) second cladding layer formed on the active layer, and an Al.sub.z Ga.sub.1-z As (0&lt;z&lt;1) current blocking layer formed above the second cladding layer, the current blocking layer having a striped groove as a current injection path. The method includes the steps of: forming a multi-layered structure on a semiconductor substrate, the multi-layered structure containing in order, an Al.sub.x Ga.sub.1-x As (0&lt;x&lt;1) first cladding layer, an Al.sub.y Ga.sub.1-y As (0&lt;y&lt;1, x&gt;y) active layer for laser oscillation, an AlGaAs (0&lt;x&lt;1) second cladding layer, a GaAs buffer layer, an Al.sub.u Ga.sub.1-u As (0&lt;u&lt;1) etching stopper layer, an Al.sub.z Ga.sub.1-z As (0&lt;z&lt;1, z&lt;u) current blocking layer, and a GaAs protective layer; etching the protective layer and the current blocking layer to form a striped groove as a current injection path; removing the exposed portion of the etching stopper layer on the bottom of the striped groove; removing the portion of the buffer layer on the bottom of the striped groove and at least one part of the protective layer by a melt-back technique; and growing an Al.sub.x Ga.sub.1-x As (0&lt;x&lt;1) third cladding layer so as to bury the striped groove therein and growing a GaAs contact layer on the third cladding layer.

Semiconductor laser device and a method of fabricating the same

A semiconductor laser device and a method for the production of the semiconductor laser device are provided, which semiconductor laser device includes a striped channel formed in a semiconductor substrate through a current blocking layer on the substrate and at least two dummy grooves formed in the current blocking layer on each side of the striped channel. Also provided are a semiconductor wafer prepared for the purpose of producing optical devices with an optical waveguide, and a method for the production of the semiconductor wafer. The semiconductor wafer includes a semiconductor substrate, the surface of which has an orientation inclined from the [100] direction to one of the [011] and [011] directions of an angle .theta. satisfying the relationship 0.1.degree.&lt;.vertline..theta..vertline.&lt;4.degree.; a plurality of striped channels formed in a substrate through a current blocking layer in the direction of the other of the [011] and [011] directions; and at least one dummy side groove formed between the striped channels, having a combined cross-sectional area on the plane perpendicular to the other direction greater than that of each of the striped channels.

Semiconductor laser device, a semiconductor wafer

A semiconductor device comprising a (111)B single-crystalline semiconductor substrate which is misoriented toward (110), and epitaxial layers grown on the substrate by molecular beam epitaxy, whereby the crystallinity and luminescence efficiency of epitaxial layers are significantly improved.

Semiconductor device with substrate misorientation

A semiconductor laser device is disclosed which comprises a semiconductor substrate and a multi-layered crystal structure disposed on the substrate, the multi-layered crystal structure containing a first cladding layer, a quantum-well active layer for laser oscillation, and a second cladding layer with a striped ridge portion for current injection, wherein the difference in the effective refractive index between the region underneath the striped ridge portion and the adjacent regions thereto is greater in the vicinity of at least one of the facets than inside of the facets.

An optical semiconductor device is disclosed that comprises a quantum-well structure as an active region and exhibits a nonlinear optical effect with regard to light of energy near the band gap between the allowed band edges in the active region. The quantum-well structure of this device is composed of alternate layers consisting of at least one first semiconductor layer with a thickness smaller than the de Broglie wavelength of carriers and at least two second semiconductor layers with a band gap greater than that of the first semiconductor layer, the alternate layers being formed along a crystal orientation in the zinc-blende structure. The second semiconductor layers mentioned above are of an indirect transition type.

Optical semiconductor device

A semiconductor laser device is disclosed which comprises a semiconductor substrate, a striped mesa disposed on the substrate and having an active layer for laser oscillation, a current injection layer disposed on the striped mesa and having a width smaller than that of the striped mesa, and a burying layer disposed on both sides of the current injection layer so as to come into contact with the side walls of the current injection layer, the burying layer being capable of absorbing laser light produce in the active layer and of preventing current from flowing through the outside of the striped mesa.

A semiconductor apparatus comprises a step-shaped substrate and a multiple-layered crystal structure formed on the substrate, said multiple-layered crystal structure is of a superlatticed layer which is composed of alternate layers consisting of plural thin layers grown by molecular beam epitaxy.

Semiconductor apparatus

A semiconductor laser device comprising a substrate of a first conductivity type having a mesa; a first semiconductor layer of a second conductivity type which is formed on the upper surface of the substrate other than the mesa to form a flat plane including the top face of the mesa; a laser oscillation region which is formed on the flat plane and includes an active area for laser oscillation; and a multi-layer structure burying the laser oscillation region, the multi-layer structure comprising a high resistance layer formed on the first semiconductor layer and burying both sides of the laser oscillation region, and a second semiconductor layer of the first conductivity type formed on the high resistance layer.

Growing community of inventors

Tenri, Japan

Takahiro Suyama