Mitsubishi Denki Kabushiki Kaisha

Wataru Susaki

Hirofumi Namizaki

Toshio Tanaka

Akihiro Shima

Hisao Kumabe

Kunihiko Isshiki

Yoshihiro Kokubo

Ryoichi Hirano

Takashi Murakami

Norio Hayafuji

Masayoshi Takemi

Saburo Takamiya

Hideyo Higuchi

Yasushi Sakakibara

Etsuji Oomura

Hirofumi Kan

A semiconductor laser for producing visible light includes a first conductivity type semiconductor substrate; a first conductivity type semiconductor first cladding layer, a semiconductor active layer of GaAs.sub.1-y P.sub.y (y.ltoreq.0.45), and a second conductivity type second cladding layer, the first cladding layer, the active layer, and the second cladding layer being successively disposed on the semiconductor substrate, the first and second cladding layers having substantially the same composition and a different composition from the active layer, thereby forming heterojunctions with the active layer, and having a lattice constant different from the lattice constant of the active layer and introducing stress into the active layer without producing dislocations in the active layer; and first and second electrodes electrically connected to the substrate and the second cladding layer, respectively.

Semiconductor laser producing visible light

A high-power AlGaAs/GaAs laser device comprises: a ridge formed on the top surface of a substrate from one end to the opposite end, thereof wherein the width of the ridge is made narrower in regions near both the ends and wider in a middle region; a depression is formed in the wider region of the ridge; a clad layer is grown epitaxially over the top surface of the substrate; and an active layer is grown epitaxially on the clad layer, wherein the thickness of the active layer is thinner in portions just above the narrower ridge regions and relatively thicker in a portion just above the wider ridge region.

Semiconductor laser device fabricating method

A method of producing a semiconductor laser which comprises sequentially depositing a lower cladding layer, an active layer, and an upper cladding layer on a substrate, forming a V shaped groove in the deposited layers at least reaching the lower cladding layer, the groove extending in a direction perpendicular to the direction between the surfaces that are to become resonator end surfaces, growing a semiconductor layer having a larger energy band gap than that of the active layer in the groove while retaining the V shaped groove, and cleaving the substrate and layers along the V shaped groove.

Method of making and separating semiconductor lasers

A method for producing a semiconductor laser which comprises sequentially depositing a lower cladding layer, an active layer, and an upper cladding layer on a substrate, forming a V shaped groove in the deposited layers at least reaching the lower cladding layer, the groove extending in a direction perpendicular to the direction between the surfaces that are to become resonator end surfaces, growing a semiconductor layer having a larger energy band gap than that of the active layer in the groove while retaining the V shaped groove, and cleaving the substrate and layers along the V shaped groove.

Semiconductor laser

A semiconductor laser device in which the thickness of an active layer is made smaller than or equal to 0.04 .mu.m only in regions near the laser light emitting facets and the active layer in the other inner region is made to have a sufficient thickness not to cause a conspicuous deterioration in quality of the layer, that is, a thickness larger than 0.04 .mu.m.

Semiconductor laser device

A high-power AlGaAs/GaAs laser device comprises: a ridge formed on the top surface of a substrate from one end thereof to the opposite end, wherein the width of the ridge is made narrower in regions near both the ends and wider in a middle region; a depression is formed in the wider region of the ridge; a clad layer is grown epitaxially over the top surface of the substrate; and an active layer is grown epitaxially on the clad layer, wherein the thickness of the active layer is thinner in portions just above the narrower ridge regions and relatively thicker in a portion just above the wider ridge region.

A semiconductor laser apparatus in accordance with the present invention comprise: a semiconductor laser chip including a resonator with a couple of opposite end faces of which one is provided with an antireflective coating and the other with a highly reflective coating; a stem having a main surface to which the chip is attached with the end faces being vertical to the main surface; and a photoelectric conversion device, a major surface of which absorbs a part of a laser beam emitted from said one end face thereby to monitor intensity of the beam and reflects the remaining part of the beam for practical use.

Semiconductor laser apparatus

Laser light guided by a coupled waveguide (formed by difference in refractive index between n-type and p-type AlGaAs clad layers (2) and (4) and an undoped AlGaAs active layer (3) and difference in refractive index between the p-type AlGaAs clad layers (4) and (7) and a p-type AlGaAs waveguide layer (6)) is guided only by the p-type AlGaAs waveguide layer (6) in the vicinity of end surfaces (40, 42), not to be coupled with the undoped AlGaAs active layer (3). Therefore, surface regions of the end surfaces (40, 42) reflecting the laser light are formed by the p-type AlGaAs clad layers (4, 7) and the p-type AlGaAs waveguide layer (6) being larger in forbidden bandwidth.

A semiconductor laser device is fabricated by forming a first semiconductor layer of N type GaAs to be a current narrowing layer on a P type GaAs semiconductor substrate, forming a second semiconductor layer of P type AlGaAs on the first semiconductor layer, removing said second semiconductor layer by etching except the proximity of the portion to be the end surface of a resonator, forming a striped groove which is deep enough to penetrate the first semiconductor layer and extends to that direction which crosses the surface to be the end surface of the resonator and, depositing a lower clad layer, an active layer, an upper layer and a contact layer in this order.

Method for fabricating a semiconductor laser device

In order to prevent the output characteristic of a semiconductor laser from being saturated at higher temperatures due to the thyristor effect of a combination of the semiconductor layers thereof, an intermediate layer of a conductivity type the same as that of the substrate and opposite that of the first semiconductor layer is provided between the substrate and the first layer. Due to the relatively low carrier density of the intermediate layer, oscillation can be stably carried out even at higher temperatures without triggering the thyristor structure.

Buried semiconductor laser avoiding thyristor action

A first growth melting solution which has been used for the growth of a first layer is first replaced with a third melting solution and then with a second growth melting solution for the growth of a second layer. Using the third melting solution of a composition intermediate the first and second melting solutions effectively suppresses supersaturate or unsaturation of the solute during replacement of the melting solutions.

Liquid phase epitaxial growth technique

A first N-AlGaAs and a second N-GaAs layer are successively grown on an I-GaAs substrate. A third N-AlGaAs, a fourth P-AlGaAs and a fifth N-GaAs layer superpose one another on the second layer except for one lateral portion. Those portions of the five layers remote from the exposed second layer portion are changed into a P.sup.+ type and surrounded by a P zone. A positive and a negative electrode are located on the fifth layer and the exposed second layer portion respectively. The negative electrode is nearest to a laser region located in the second layer and can be secured to a heat sink.

N type GaAlAs, GaAs and GaAlAs layers are successively grown on a semi-insulating GaAs substrate doped with Cr. Zn is diffused into predetermined portions of those layers to a depth reaching the substrate to form pn junctions between the original n type regions of the layers and their regions are converted to the p from the n type conductivity. The pn junction formed in the GaAs layer serves as a light emitting region.

N type CaAlAs, GaAs and GaAlAs layers are successively grown on a semi-insulating GaAs substrate doped with Cr to form a semiconductor chip. Predetermined portions of those layers are selectively etched away to a depth reaching the substrate. Then a P type GaAlAs layer is epitaxially grown on the etched portions to restore the original shape of the chip. The chip is heated to form a pn junction in at least the GaAs layer serving as a light emitting region.

Growing community of inventors

Itami, Japan

Wataru Susaki