Abstract: In order to provide a highly reliable silicon-germanium semiconductor optical element of high luminous efficiency or of low power consumption that can reduce or prevent the occurrence of dislocations or crystal defects on the interface between a light emitting layer or a light absorption layer and a cladding layer, in a silicon-germanium semiconductor optical element, a germanium protective layer 11 of non-light emission is disposed between a germanium light emitting layer or the light absorption layer 10 and a cladding layer 12 disposed above a substrate. The germanium protective layer 11 has the electrical conductivity different from electrical conductivity of the germanium light emitting layer or the light absorption layer 10.

Abstract: The light emitting device includes an active layer formed on a semiconductor substrate for emitting light, a semiconductor layer of a first conductivity type electrically connected to one end of the active layer, a semiconductor layer of a second conductivity type electrically connected to the other end of the active layer, first and second electrodes, a feedback mechanism for laser oscillation, and a waveguide for guiding the light emitted from the active layer, in which the active layer is made of a semiconductor having an affinity with a silicon CMOS process, and the semiconductor layer of the first conductivity type and the semiconductor layer of the second conductivity type, and the waveguide are each made of silicon as a part of the semiconductor substrate.

Abstract: To provide a light-emitting element where electrons are efficiently injected into a Ge light emission layer and light can be efficiently emitted, the light-emitting element has a barrier layer 3 which is formed on an insulating film 2, worked in a size in which quantum confinement effect manifests and made of monocrystalline Si, a p-type diffused layer electrode 5 and an n-type diffused layer electrode 6 respectively provided at both ends of the barrier layer 3, and a monocrystalline Ge light emission part 13 provided on the barrier layer 3 between the electrodes 5, 6. At least a part of current that flows between the electrodes 5, 6 flows in the barrier layer 3 in a horizontal direction with respect to a substrate 1.

Abstract: To provide a light-emitting element where electrons are efficiently injected into a Ge light emission layer and light can be efficiently emitted, the light-emitting element has a barrier layer 3 which is formed on an insulating film 2, worked in a size in which quantum confinement effect manifests and made of monocrystalline Si, a p-type diffused layer electrode 5 and an n-type diffused layer electrode 6 respectively provided at both ends of the barrier layer 3, and a monocrystalline Ge light emission part 13 provided on the barrier layer 3 between the electrodes 5, 6. At least a part of current that flows between the electrodes 5, 6 flows in the barrier layer 3 in a horizontal direction with respect to a substrate 1.

Abstract: An APD in which a first undoped semiconductor region and a second undoped semiconductor region having different semiconductor materials and arranged on an insulating film configure a photo-absorption layer and a multiplying layer, respectively, is employed, whereby crystalline of an interface between the photo-absorption layer and the multiplying layer becomes favorable, and a dark current caused by crystal defects can be decreased. Accordingly, light-receiving sensitivity of an avalanche photodiode can be improved. Further, doping concentration of the light-receiving layer and the multiplying layer can be made small. Therefore, a junction capacitance of the diode can be decreased, and a high-speed operation becomes possible.

Abstract: In order to provide a highly reliable silicon-germanium semiconductor optical element of high luminous efficiency or of low power consumption that can reduce or prevent the occurrence of dislocations or crystal defects on the interface between a light emitting layer or a light absorption layer and a cladding layer, in a silicon-germanium semiconductor optical element, a germanium protective layer 11 of non-light emission is disposed between a germanium light emitting layer or the light absorption layer 10 and a cladding layer 12 disposed above a substrate. The germanium protective layer 11 has the electrical conductivity different from electrical conductivity of the germanium light emitting layer or the light absorption layer 10.

Abstract: The light emitting device includes an active layer formed on a semiconductor substrate for emitting light, a semiconductor layer of a first conductivity type electrically connected to one end of the active layer, a semiconductor layer of a second conductivity type electrically connected to the other end of the active layer, first and second electrodes, a feedback mechanism for laser oscillation, and a waveguide for guiding the light emitted from the active layer, in which the active layer is made of a semiconductor having an affinity with a silicon CMOS process, and the semiconductor layer of the first conductivity type and the semiconductor layer of the second conductivity type, and the waveguide are each made of silicon as a part of the semiconductor substrate.

Abstract: An object of the present invention is to provide a germanium laser diode that can be easily formed on a substrate such as silicon by using a normal silicon process and can emit light efficiently. A germanium light-emitting device according to the present invention is a germanium laser diode characterized in that tensile strain is applied to single-crystal germanium serving as a light-emitting layer to be of a direct transition type, a thin semiconductor layer made of silicon, germanium or silicon-germanium is connected adjacently to both ends of the germanium light-emitting layer, the thin semiconductor layer has a certain degree of thickness capable of preventing the occurrence of quantum confinement effect, another end of the thin semiconductor layer is connected to a thick electrode doped with impurities at a high concentration, the electrode is doped to a p type and an n type, a waveguide is formed so as not to be in direct contact with the electrode, and a mirror is formed at an end of the waveguide.

Abstract: A semiconductor photodiode includes a semiconductor substrate; a first conduction type first semiconductor layer formed above the semiconductor substrate; a high resistance second semiconductor layer formed above the first semiconductor layer; a first conduction type third semiconductor layer formed above the second semiconductor layer; and a second conduction type fourth semiconductor layer buried in the second semiconductor layer, in which the fourth semiconductor layer is separated at a predetermined distance in a direction horizontal to the surface of the semiconductor substrate.

Abstract: A germanium light-emitting device emitting light at high efficiency is provided by using germanium of small threading dislocation density. A germanium laser diode having a high quality germanium light-emitting layer is attained by using germanium formed over silicon dioxide. A germanium laser diode having a carrier density higher than the carrier density limit that can be injected by existent n-type germanium can be provided using silicon as an n-type electrode.

Abstract: A semiconductor photodiode device includes a semiconductor substrate, a first buffer layer containing a material different from that of the semiconductor substrate in a portion thereof, a first semiconductor layer formed above the buffer layer and having a lattice constant different from that of the semiconductor substrate, a second buffer layer formed above the first semiconductor layer and containing an element identical with that of the first semiconductor layer in a portion thereof, and a second semiconductor layer formed above the buffer layer in which a portion of the first semiconductor layer is formed of a plurality of island shape portions each surrounded with an insulating film, and the second buffer layer allows adjacent islands of the first semiconductor layer to coalesce with each other and is in contact with the insulating film.

Abstract: An object of the present invention is to provide a germanium laser diode that can be easily formed on a substrate such as silicon by using a normal silicon process and can emit light efficiently. A germanium light-emitting device according to the present invention is a germanium laser diode characterized in that tensile strain is applied to single-crystal germanium serving as a light-emitting layer to be of a direct transition type, a thin semiconductor layer made of silicon, germanium or silicon-germanium is connected adjacently to both ends of the germanium light-emitting layer, the thin semiconductor layer has a certain degree of thickness capable of preventing the occurrence of quantum confinement effect, another end of the thin semiconductor layer is connected to a thick electrode doped with impurities at a high concentration, the electrode is doped to a p type and an n type, a waveguide is formed so as not to be in direct contact with the electrode, and a mirror is formed at an end of the waveguide.

Abstract: A semiconductor photodiode device includes a semiconductor substrate, a first buffer layer containing a material different from that of the semiconductor substrate in a portion thereof, a first semiconductor layer formed above the buffer layer and having a lattice constant different from that of the semiconductor substrate, a second buffer layer formed above the first semiconductor layer and containing an element identical with that of the first semiconductor layer in a portion thereof, and a second semiconductor layer formed above the buffer layer in which a portion of the first semiconductor layer is formed of a plurality of island shape portions each surrounded with an insulating film, and the second buffer layer allows adjacent islands of the first semiconductor layer to coalesce with each other and is in contact with the insulating film.

Abstract: A semiconductor photodiode includes a semiconductor substrate; a first conduction type first semiconductor layer formed above the semiconductor substrate; a high resistance second semiconductor layer formed above the first semiconductor layer; a first conduction type third semiconductor layer formed above the second semiconductor layer; and a second conduction type fourth semiconductor layer buried in the second semiconductor layer, in which the fourth semiconductor layer is separated at a predetermined distance in a direction horizontal to the surface of the semiconductor substrate.

Abstract: A manufacturing method of a semiconductor device in which the oxygen and carbon concentrations are reduced at the interface of each layer making up the semiconductor multilayer film. A first semiconductor layer is formed on a single-crystal substrate in a first reactor; the substrate is transferred from the first reactor to a second reactor through a transfer chamber; and a second semiconductor layer is formed on the first semiconductor layer in the second reactor. During substrate transfer, hydrogen is supplied when the number of hydrogen atoms bonding with the surface atoms of the first semiconductor layer is less than the number of surface atoms of the first semiconductor layer, and the supply of hydrogen is stopped when the number of hydrogen atoms bonding with the surface atoms of the first semiconductor layer is greater than the number of surface atoms of the first semiconductor layer.

Abstract: A bipolar transistor is provided in which both the base resistance and the base-collector capacitance are reduced and which is capable of operating at a high cutoff frequency. The semiconductor device is structured so that the emitter and extrinsic base are separated from each other by an insulator sidewall and the bottom faces of the insulator sidewall, and the emitter are approximately on the same plane. The extrinsic base electrode and the collector region are separated from each other by an insulator.

Abstract: A high quality silicon carbide (SiC) layer being substantially lower in threading dislocation density than a prior layer is formed on silicon (Si) substrate. A semiconductor device is fabricated in such a way that a semiconductor buffer layer containing Si in part and being higher in defect density than a Si substrate is formed on the Si substrate on the upper portion of which are formed a plurality of pairs of facets being mirror-symmetrical to the surface orientation of a semiconductor substrate, further on the top of the layer a SiC layer is sequentially formed.

Abstract: An object of the invention is to clear up factors in deterioration due to optical reflection and to provide an optical transmission apparatus and an optical transmission system in which a superior optical transmission characteristic can be obtained for analog signals even if a reflection phenomenon occurs in an optical transmission line. There are provided a frequency converter (3) for converting the frequency band of a to-be-transmitted electric signal into a predetermined frequency band higher that this frequency band, and a semiconductor laser (4) serving as an electro-optic converter for performing electro-optic conversion upon the frequency-converted electric signal.

Abstract: An object of the present invention is to provide an optical transmitter that can suppress degradation of distortion characteristic and RIN characteristic caused by relaxation oscillation at high temperature by controlling average driving current of a light emitting element so that the average optical output power of the light emitting element is increased as the temperature increases like a case where the environmental temperature around the light emitting element increases.

Abstract: Up and down signal levels in a wireless base station and a forward base station can be automatically adjusted into predetermined levels respectively with a simple configuration. In an interface portion 12, a pilot signal P of a predetermined level is generated by a pilot signal generator 120, and multiplexed with a down transmission signal 111 from a wireless base station 11 by a multiplexer 121. The multiplexed signal is amplified with a constant gain by a down signal amplifier 122, then converted into a down optical signal by an electro-optic converter 123, wavelength-multiplexed by an optical multi/demultiplexer 124, sent out to an optical fiber 15, and transmitted to a forward base station 13. In the forward base station 13, the down optical signal wavelength-demultiplexed by an optical multi/demultiplexer 124 is converted into a down electric signal by an opto-electric converter 125, and the pilot signal P is demultiplexed by a demultiplexer 133.