Abstract: A gallium nitride group compound semiconductor light-emitting device comprises a substrate and a layered structure provided on the substrate. The layered structure includes: an active layer; an upper cladding layer and a lower cladding layer which is located closer to the substrate than the upper cladding layer, the active layer interposed between the cladding layers; an internal current constricting layer having an opening for constricting a current within a selected region of the active layer, the internal current constricting layer being provided on the upper cladding layer; a surface protecting layer for covering the internal current constricting layer and an exposed surface of the upper cladding layer in the opening of the internal current constricting layer; and a regrowth layer provided on the surface protecting layer. The surface protecting layer serves as a protecting layer for the upper cladding layer and the internal current constricting layer in a step of forming the regrowth layer.

Abstract: A gallium nitride type compound semiconductor light-emitting device of the present invention includes: a substrate; a buffer layer, formed on the substrate, having a thick region and a thin region in terms of a thickness taking a surface of the substrate as a reference level; and a semiconductor layered structure, formed on the buffer layer, at least including an undoped gallium nitride type compound semiconductor layer, a gallium nitride type compound semiconductor active layer, and a P-type gallium nitride type compound semiconductor cladding layer.

Abstract: A semiconductor laser device having high performance, low operating voltage, and long service life, and a method for fabricating the same are provided. A semiconductor multilayer film including an active layer for use of laser beam oscillation is stacked on a substrate. Then a clad layer composed of p-type AlGaAs doped with a p-type impurity Mg, and a contact layer composed of p-type GaAs doped also with Mg are grown by an LPE growth process, and further a surface layer having a high-resistance portion present in the contact layer and low in carrier concentration is removed. The active layer for use of laser beam oscillation is arranged in a substantially center of an end surface from which the laser beam is emitted.

Abstract: The gallium nitride compound semiconductor light emitting element includes: a substrate; a first semiconductor multilayer structure including, at least, an active layer, a first cladding layer of a first conductivity type, and a second cladding layer of a second conductivity type, the first and second cladding layers sandwiching the active layer therebetween; a dry etching stop layer of the second conductivity type formed on the first semiconductor multilayer structure; and a second semiconductor multilayer structure formed on the dry etching stop layer.

Abstract: A semiconductor laser device having high performance, low operating voltage, and long service life, and a method for fabricating the same are provided. A semiconductor multilayer film including an active layer for use of laser beam oscillation is stacked on a substrate. Then a clad layer composed of p-type AlGaAs doped with a p-type impurity Mg, and a contact layer composed of p-type GaAs doped also with Mg are grown by an LPE growth process, and further a surface layer having a high-resistance portion present in the contact layer and low in carrier concentration is removed. The active layer for use of laser beam oscillation is arranged in a substantially center of an end surface from which the laser beam is emitted.

Abstract: After the active layer including indium is formed, the evaporation preventing layer is formed at a temperature which does not cause liberation of indium. The p-type Al.sub.X Ga.sub.1-X N (0.ltoreq.X.ltoreq.1) or the like is used for the evaporation preventing layer. Increasing the substrate temperature to as high as 1020.degree. C. for forming the upper cladding layer does not cause liberation of indium from the active layer because the evaporation preventing layer is provided. As a result, the composition ratio of indium can be easily controlled and the high-quality active layer and the high-quality interface between the active layer and the upper cladding layer can be provided.

Abstract: After the active layer including indium is formed, the evaporation preventing layer is formed at a temperature which does not cause liberation of indium. The p-type Al.sub.x Ga.sub.1-x N (0.ltoreq.X.ltoreq.1) or the like is used for the evaporation preventing layer. Increasing the substrate temperature to as high as 1020.degree. C. for forming the upper cladding layer does not cause liberation of indium from the active layer because the evaporation preventing layer is provided. As a result, the composition ratio of indium can be easily controlled and the high-quality active layer and the high-quality interface between the active layer and the upper cladding layer can be provided.

Abstract: A PLL circuit includes a PLLic formed into an integrated circuit; a loop filter for receiving an output signal from the PLLic; a voltage-controlled oscillator having an oscillation frequency which is controlled according to an output signal of the loop filter for applying a controlled oscillation output signal to the PLLic, the voltage-controlled oscillator including a resonator and a negative resistor circuit; wherein a buffer amplifier functioning as a part of the voltage-controlled oscillator is incorporated into the PLLic, and the resonator and the negative resistor circuit of the voltage-controlled oscillator are disposed outside of the PLLic.

Abstract: 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.

Abstract: The size precision of a surface mountable electronic part is improved and a production thereof is simplified. The surface mountable electronic part is constructed such that a circuit substrate is housed in a shield case of which an end side is open, and the shield case is a resin case having a shield film. A connection pattern is formed on the inner surface of the case, with one end of the connection pattern being disposed so as to correspond to an external connection land of the circuit substrate, and with the other end of the connection pattern extending to the open end of the case.

Abstract: 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.

Abstract: 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<x<1) first cladding layer formed on the substrate, an Al.sub.y Ga.sub.1-y As (0<y<1, x>y) active layer for laser oscillation formed on the first cladding layer, an Al.sub.x Ga.sub.1-x As (0<x<1) second cladding layer formed on the active layer, and an Al.sub.z Ga.sub.1-z As (0<z<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<x<1) first cladding layer, an Al.sub.y Ga.sub.

Abstract: A constant torque ball joint employs upper and lower bearing cup pieces made of a self-lubricating material to journal the ball portion of a ball stud with their segmental spherical internal surfaces and also employs a lower elastic material block having a longitudinal elastic modulus Eo of 1.5 to 10 kg/mm.sup.2 to substantially enclose tightly the outer surface of the upper and lower bearing cup pieces. The upper and lower bearing cup pieces and the lower elastic block with the ball portion of the ball stud are mounted whereby a small space is left between the upper and lower bearing cup pieces which are inserted in the socket cavity of a metallic socket joint rod. A metallic cover disc is applied over these inserted members and the end rim of the socket cavity is swaged to crimp the cover disc to substantially completely enclose the bearing cup pieces and the elastic block within the socket cavity and the cover disc.

Abstract: A constant torque ball joint employs upper and lower bearing pieces made of a self-lubricating material to journal the ball portion of a ball stud with their segmental semi-spherical internal surfaces and also employs upper and lower elastic material blocks having a longitudinal elastic modulus Eo of 1.5 to 10 kg/mm.sup.2 to substantially enclose tightly respectively the outer surfaces of the upper and lower bearing pieces. The upper and lower bearing pieces and the upper and lower elastic blocks with the ball portion of the ball stud are mounted whereby a small space is left between the upper and lower bearing pieces which are inserted in the socket cavity of a metallic socket joint rod. A metallic cover disc is applied over these inserted members and the end rim of the socket cavity is swaged to crimp the cover disc to substantially completely enclose the bearing pieces and the elastic blocks within the socket cavity and the cover disc.