Abstract: In an avalanche photodiode provided with a substrate including a first electrode and a first semiconductor layer, formed of a first conductivity type, which is connected to the first electrode, the configuration is in such a way that, at least an avalanche multiplication layer, a light absorption layer, and a second semiconductor layer having a bandgap that is larger than that of the light absorption layer are layered on the substrate; a second conductivity type conductive region is formed in the second semiconductor layer; and the second conductivity type conductive region is arranged so as to be connected to a second electrode. With the foregoing configuration, an avalanche photodiode having a small dark current and a high long-term reliability can be provided with a simple process.

Abstract: A semiconductor light-receiving device includes: a substrate; a p-type conductive layer, a light absorption layer having a smaller bandgap than that of incident light, a multiplication layer producing avalanche multiplication, and an n-type window layer laminated in that order on the substrate; an n-type conductive layer in a region of part of the n-type window layer; and a first p-type conductive region in a region of the n-type window layer that is not in contact with the n-type conductive layer, wherein the first p-type conductive region does not reach the multiplication layer and is not in contact with any electrode to which power is supplied from outside.

Abstract: A semiconductor photodetector device includes a header, a high frequency amplifier, and a submount having a top surface. The high frequency amplifier is located on the header and has a top surface with a high frequency grounding pad disposed on the top surface of the amplifier. First and second electrode pads are located on the top surface of the submount. A semiconductor photodetector having a footprint smaller than the first electrode pad is bonded to the first electrode pad. The high frequency grounding pad is connected to the second electrode pad by a wire.

Abstract: A light receiving element includes a substrate of a first conduction type, a light absorbing layer of the first conduction type formed on the substrate, a diffusion layer of a second conduction type formed on a portion of the light absorbing layer, a window layer of the first conduction type formed on the light absorbing layer so as to surround the diffusion layer and having a bandgap larger than that of the light absorbing layer, an anode electrode formed on the diffusion layer, and a cathode electrode provided on the substrate so as to contact the substrate without contacting each of the window layer and the light absorbing layer, wherein a groove is formed which surrounds a boundary between the diffusion layer and the window layer as viewed in plan and extends through the window layer and the light absorbing layer as viewed in section.

Abstract: A light receiving element includes a substrate of a first conduction type, a light absorbing layer of the first conduction type formed on the substrate, a diffusion layer of a second conduction type formed on a portion of the light absorbing layer, a window layer of the first conduction type formed on the light absorbing layer so as to surround the diffusion layer and having a bandgap larger than that of the light absorbing layer, an anode electrode formed on the diffusion layer, and a cathode electrode provided on the substrate so as to contact the substrate without contacting each of the window layer and the light absorbing layer, wherein a groove is formed which surrounds a boundary between the diffusion layer and the window layer as viewed in plan and extends through the window layer and the light absorbing layer as viewed in section.

Abstract: A semiconductor photodetector device includes a header, a high frequency amplifier, and a submount having a top surface. The high frequency amplifier is located on the header and has a top surface with a high frequency grounding pad disposed on the top surface of the amplifier. A semiconductor photodetector having a footprint smaller than the top surface of the submount is located on the top surface of the submount. The top surface of the submount has thereon an electrode pad to which the semiconductor photodetector is bonded, and an electrode pad disposed adjacent the electrode pad. The high frequency grounding pad is connected to the electrode pad by a wire.

Abstract: An avalanche photodiode including a first electrode; and a substrate including a first semiconductor layer of a first conduction type electrically connected to the first electrode, in which at least an avalanche multiplication layer, a light absorption layer, and a second semiconductor layer of a second conduction type with a larger band gap than the light absorption layer are deposited on the substrate. The second semiconductor layer is separated into inner and outer regions by a groove formed therein, the inner region electrically connected to a second. With the configuration, the avalanche photodiode has a low dark current and high long-term reliability. In addition, the outer region includes an outer trench, and at least the light absorption layer is removed by the outer trench to form a side face of the light absorption layer. With the configuration, the dark current can be further reduced.

Abstract: A light receiving element comprises: a photodiode including an optical waveguide, an end surface of the optical waveguide being a light receiving surface of the photodiode; a signal electrode and a bias electrode on a common surface of the photodiode, the signal electrode being connected to an anode of the photodiode, the bias electrode being connected to a cathode of the photodiode; an insulating film on the bias electrode; and a metal electrode on the insulating film.

Abstract: A semiconductor light detecting element includes: a semiconductor substrate; and a distributed Bragg reflector layer of a first conductivity type, an optical absorption layer, and a semiconductor layer of a second conductivity type, sequentially laminated on the semiconductor substrate. The distributed Bragg reflector layer includes first and second alternately laminated semiconductor layers with different band-gap wavelengths, sandwiching the wavelength of detected incident light. The sum of thicknesses a first and a second semiconductor layer is approximately one-half the wavelength of the incident light detected.

Abstract: An avalanche photodiode including a semiconductor substrate of a first conductivity type, an avalanche multiplication layer, an electric field control layer, a light absorption layer, and a window layer wherein the layers are laid one on another in this order on a major surface of the semiconductor substrate, an impurity region of a second conductivity type in a portion of the window layer, and a straight electrode on the impurity region and connected to the impurity region, the straight electrode being straight as viewed in a plan view facing the major surface of the semiconductor substrate.

Abstract: A semiconductor light-detecting device includes: a semi-insulating substrate; and n light-detecting elements (n is a natural number equal to or larger than 4) electrically isolated from each other and on the semi-insulating substrate. Each light-detecting element includes a conductive layer of a first conductivity type, a light absorption layer, a window layer, and an impurity diffusion region of a second conductivity type, which are laminated, one on another, on the semi-insulating substrate. The light absorption layer is a photoelectrical converter. The impurity diffusion region is located in part of the window layer and serves as a light-detecting section. A part of the conductive layer and the light absorption layer use the same material. The n light-detecting elements are not all located on a common straight line.

Abstract: A semiconductor light-detecting element includes: a semiconductor substrate of a first conductivity type; a light absorption recoupling layer of the first conductivity type, a multilayer reflection film of the first conductivity type, a light absorbing layer, and a window layer, which are laminated, in that order, on the semiconductor substrate; a doped region of a second conductivity type in part of the window layer; a first electrode connected to the doped region; and a second electrode connected to an underside of the semiconductor substrate. The band gap energy of the window layer is larger than the band gap energy of the light absorbing layer, and the band gap energy of the light absorption recoupling layer is smaller than the band gap energy of the semiconductor substrate.

Abstract: A semiconductor photodetector comprises: a semiconductor substrate; a first multilayer reflective layer on a first surface of the semiconductor substrate and including semiconductor layers; a first optically-resonant layer on the first multilayer reflective layer; a second multilayer reflective layer on the first optically-resonant layer and including semiconductor layers; a light absorbing layer on the second multilayer reflective layer; a reflective film on the light absorbing layer; and an antireflective film on a second surface of the semiconductor substrate. The first optically-resonant layer has a larger thickness than the semiconductor layers of the first and second multilayer reflective layers. The combined optical thickness of the layers between the second multilayer reflective layer and the reflective film is not equal to the optical thickness of the first optically-resonant layer.

Abstract: An avalanche photodiode including a first electrode; and a substrate including a first semiconductor layer of a first conduction type electrically connected to the first electrode, in which at least an avalanche multiplication layer, a light absorption layer, and a second semiconductor layer of a second conduction type with a larger band gap than the light absorption layer are deposited on the substrate. The second semiconductor layer is separated into inner and outer regions by a groove formed therein, the inner region electrically connected to a second. With the configuration, the avalanche photodiode has a low dark current and high long-term reliability. In addition, the outer region includes an outer trench, and at least the light absorption layer is removed by the outer trench to form a side face of the light absorption layer. With the configuration, the dark current can be further reduced.

Abstract: An optical semiconductor device comprises a distributed Bragg reflector layer of a first conductivity type, an optical absorption layer, and a semiconductor layer of a second conductivity type, sequentially formed on a semiconductor substrate; wherein said Bragg reflection layer of the first conductivity type has first semiconductor layers having a band gap wavelength larger than the wavelength of incident light, and second semiconductor layers having a band gap wavelength smaller than the wavelength of incident light; and an optical layer thickness of each of said first semiconductor layers is larger than the optical layer thickness of each of said second semiconductor layers.

Abstract: A semiconductor light detecting element includes: a semiconductor substrate; and a distributed Bragg reflector layer of a first conductivity type, an optical absorption layer, and a semiconductor layer of a second conductivity type, sequentially laminated on the semiconductor substrate. The distributed Bragg reflector layer includes first and second alternately laminated semiconductor layers with different band-gap wavelengths, sandwiching the wavelength of detected incident light. The sum of thicknesses a first and a second semiconductor layer is approximately one-half the wavelength of the incident light detected.

Abstract: An optical semiconductor device includes a distributed Bragg reflection layer of a first conductivity type, a distortion elaxation layer of the first conductivity type, a light absorbing layer, and a semiconductor layer of a second conductivity type, sequentially arranged on a semiconductor substrate. The distortion relaxation layer the same material as the semiconductor substrate. The total optical length of layers between the distributed Bragg reflection layer and the light absorbing layer is an integer multiple of one-half the wavelength of incident light that is detected.

Abstract: A semiconductor light detecting element comprises: a semiconductor substrate having a first major surface and a second major surface opposite each other; a first reflective layer, an absorptive layer, a phase adjusting layer, and a second reflective layer sequentially disposed, from the semiconductor substrate, on the first major surface of the semiconductor substrate; and an anti-reflection film on the second major surface of the semiconductor substrate. The first reflective layer is a multilayer reflective layer including laminated semiconductor layers having different refractive indices; the absorptive layer has a band gap energy smaller than band gap energy of the semiconductor substrate; the phase adjusting layer has a band gap energy larger than the band gap energy of the absorptive layer; and the first reflective layer contacts the absorptive layer, without intervention of other layers.

Abstract: A semiconductor light detecting device includes an n-contact layer selectively disposed on an Fe—InP substrate. An optical waveguide layer is disposed on the n-contact layer and includes an n-cladding layer, a light absorption layer, and a p-cladding layer, laminated on one another over the n-contact layer, in that order. An Fe—InP current blocking layer is disposed on the n-cladding layer such that sides of the optical waveguide layer are buried in the Fe—InP current blocking layer. A p-electrode includes a contact electrode electrically connected to the p-cladding layer of the optical waveguide layer, a lead-out electrode portion extending on a side wall of the current blocking layer from the contact electrode and extending on the Fe—InP substrate, and an electrode pad disposed on a surface of the Fe—InP substrates with an SiN film between the electrode pad and the surface of the Fe—InP substrate and connected to the lead-out electrode portion.

Abstract: A semiconductor light detecting element having a mesa structure comprises: a first semiconductor layer having n-type conductivity located on a semiconductor substrate, a light absorbing layer located on the first semiconductor layer, and a second semiconductor layer located on the light absorbing layer; a burying layer burying peripheries of the light absorbing layer and the second semiconductor layer. The burying layer has a band gap larger than the band gap of the light absorbing layer. The second semiconductor layer has a first region having p-type conductivity, and a second region having i-type or n-type conductivity and located between the first region and the burying layer.