Mitsubishi Electric Corporation

Ryota Takemura

Masaharu Nakaji

Kazuki Yamaji

Matobu Kikuchi

Eitaro Ishimura

Nobuo Ohata

Harunaka Yamaguchi

Yoshifumi Sasahata

A ridge structure () including at least a light-absorbing layer () is provided on a semiconductor substrate (). A semiconductor embedding layer () has a refractive index lower than that of the light-absorbing layer () and embeds a side surface of the light-absorbing layer (). A semiconductor layer () has a refractive index between that of the light-absorbing layer () and that of the semiconductor embedding layer () and is provided between the side surface of the light-absorbing layer () and the semiconductor embedding layer (). The refractive index of the semiconductor layer () is n3, a wavelength of the incident light () is λ, a thickness of the semiconductor layer () in a lateral direction is in a range of −30% to +20% of λ/(4×n3).

Waveguide photodetector

A waveguide photodetector includes a first contact layer of a first conductivity type, a waveguide layer, and a second contact layer of a second conductivity type that are sequentially formed on the semiconductor substrate. The waveguide layer includes a first cladding layer of the first conductivity type disposed on a side of the first contact layer, a second cladding layer of the second conductivity type disposed on a side of the second contact layer, and the core layer disposed between the first cladding layer and the second cladding layer. The core layer includes a light absorption layer and an impurity-doped light absorption layer that has a higher concentration of a p-type impurity than that of the light absorption layer and is disposed on a side of a light incident face.

A semiconductor light-receiving element () is a semiconductor light-receiving element in which a multi-plication layer (), an electric-field control layer (), a light absorption layer () and a window layer () are sequentially formed on a semiconductor substrate (), and a p-type region () is formed in the window layer (). The p-type region () has a first p-type portion () and a second p-type portion () whose current multiplication factor due to light incidence is larger than that of the first p-type portion (). The first p-type portion () is formed as a central portion of the p-type region (), the central portion including a central axis () perpendicular to the semiconductor substrate (), and the second p-type portion () is formed on an outer periphery of the central portion in a radial direction about the central axis ().

Semiconductor light-receiving element and method of manufacturing semiconductor light-receiving element

A multiplication layer on a semiconductor substrate of n-type contains Al atoms. An electric field control layer on the multiplication layer is of p-type, and includes a high-concentration area, and a low-concentration area lower in impurity concentration than the high-concentration area which is formed outside the high-concentration area. An optical absorption layer on the electric field control layer is lower in impurity concentration than the high-concentration area. A window layer of n-type formed on the optical absorption layer is larger in band gap than the optical absorption layer. A light-receiving area of p-type is formed apart from an outer edge of the window layer, and at least partly faces the high-concentration area through the window layer and the optical absorption layer. The guard ring area of p-type which the window layer separates from the light-receiving area penetrates through the window layer to extend into the optical absorption layer.

Semiconductor light-receiving device and method for manufacturing the same

A substrate has a front surface and a back surface opposite from the front surface. An n-type layer, a multiplication layer, a p-type electric field control layer, a light absorption layer, and a window layer are layered in order on the front surface. A p-type region is provided in part of the window layer. An anode electrode is provided on the p-type region and connected to the p-type region. An anode pad and a cathode pad are provided on the back surface. First and second connecting holes penetrates the substrate. A third connecting hole penetrates from the window layer to the n-type layer. The cathode pad is electrically connected to the n-type layer via the first connecting hole. The anode pad is electrically connected to the anode electrode via the second and third connecting holes. A light-receiving region is provided on the back surface.

Back-surface-incident type light-receiving device and optical module

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.

Semiconductor light-receiving device

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.

Light receiving element

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.

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Tokyo, Japan

Ryota Takemura