Sharp Kabushiki Kaisha Corporation

Isamu Ohkubo

Masaru Kubo

Takahiro Takimoto

Naoki Fukunaga

Toshihiko Fukushima

Shigeki Hayashida

Toshimitsu Kasamatsu

Mutsumi Oka

Tatsuya Morioka

Yoshihiko Tani

Hideo Wada

Kazuhiro Natsuaki

Makoto Hosokawa

Hiroki Nakamura

Koichi Shichi

Toshifumi Yoshikawa

A light receiving device includes a silicon substrate, a first P type diffusion layer on the silicon substrate, and a P type semiconductor layer on the P type diffusion layer. On a surface part of the P type semiconductor layer, two N type diffusion layers as light receiving parts, and a second P type diffusion layer between the two N type diffusion layers are provided. On the P type semiconductor layer, an antireflection film structure composed of a first silicon oxide formed by thermal oxidation and a second silicon oxide formed by CVD is provided. A film thickness of the first silicon oxide is set at about 15 nm, thus a defect in a interface between the first silicon oxide and the P type semiconductor layer is prevented. A film thickness of the second silicon oxide is set at about 100 nm, thus a leak current between cathodes is prevented when a power supply voltage is applied for long period of time.

Light receiving element and light receiving device incorporating circuit and optical disk drive

A photodetector for an optical encoder has plural sets of segmented photodiodes, each set of which is made by two adjoining segmented photodiodes capable of coping with a scale slit having a reference resolution. Output lines of the two adjoining segmented photodiodes are connected together in each set of the photodiodes. These output lines are connected to output lines of the corresponding segmented photodiodes in the other sets. The two adjoining segmented photodiodes function like one segmented photodiode, and thereby, the resolution of the applied scale slit is made &#xbd; of the reference resolution. Thus, this photodetector easily copes with a scale slit having a half resolution of the reference resolution at low cost only by modification of wiring without changing any configuration of the segmented photodiodes.

Optical encoder photodetector array with multiple resolutions

A plurality of N-type diffusion layers are formed a specified distance apart on a P-type semiconductor layer. A P-type leak prevention layer formed between at least N-type diffusion layers prevents leaking between the diffusion layers. A dielectric film is formed in at least a light incident area on a P-type semiconductor layer including the diffusion layers and the leak prevention layer. Accordingly, provided are a split type light receiving element positively functioning as a split type light receiving element even when charge is accumulated in the dielectric film and having a uniform sensitivity throughout the entire area on a light receiving surface, and a circuit-built-in light receiving element and an optical disk device using the split type light receiving element.

Split type light receiving element and circuit-built-in light-receiving element and optical disk drive

A light receiving element, comprising a semiconductor structure comprising at least a first conductivity type semiconductor layer, a first, second conductivity type semiconductor layer provided on the first conductivity type semiconductor layer in the semiconductor structure, a second, second conductivity type semiconductor layer having an impurity concentration lower than that of the first, second conductivity type semiconductor layer, a second, first conductivity type semiconductor layer provided on the second, second conductivity type semiconductor layer, or a second, first conductivity type semiconductor layer provided within the second, second conductivity type semiconductor layer.

Light receiving element, light detector with built-in circuitry and optical pickup

A photodiode includes a first conductivity type semiconductor substrate or a first conductivity type semiconductor layer; a second conductivity type semiconductor layer provided on the first conductivity type semiconductor substrate or the first conductivity type semiconductor layer; an anti-reflection film provided on a surface of a portion of the second conductivity type semiconductor layer which is in a light receiving area; a first conductive layer provided in an area in the vicinity of the light receiving area; and a passivation layer provided on the first conductive layer. Light incident on the photodiode is detected by a junction of the one of the first conductivity type semiconductor substrate and the first conductivity type semiconductor layer, and the second conductivity type semiconductor layer. The area in the vicinity of the light receiving area includes a window area having an opening in the passivation layer for partially exposing the first conductive layer.

Photodiode device including window defined in passivation layer for removing electrostatic charge

A corrosion-resistant conductive layer (TiW layer) formed of a corrosion-resistant material is formed to extend from a bonding pad portion to an interconnection portion of a light receiving element. A semiconductor laser device according to the present invention includes the light receiving element.

Light receiving element and semiconductor laser device

A circuit-incorporating light receiving device includes an integrated circuit and a photodiode. The integrated circuit and the photodiode are provided on a single semiconductor substrate. The integrated circuit includes a transistor having a polycrystalline silicon as an emitter diffusion source and an electrode. Elements included in the integrated circuit are isolated from each other using local oxidization.

Circuit-incorporating light receiving device and method of fabricating the same

A photosensitive device includes a semiconductor substrate and a first semiconductor layer, both of a first conductivity type, with the semiconductor layer being formed on the semiconductor substrate and having a lower impurity concentration than that of the semiconductor substrate. A second semiconductor layer, of a second conductivity type, is formed on the first semiconductor layer and at least one diffusion layer of the first conductivity type is formed from the surface of the second semiconductor layer so as to reach the surface of the first semiconductor layer. The diffusion layer subdivides the second semiconductor layer into a plurality of semiconductor regions At least one photodiode portion for converting signal light into an electrical signal is formed at a junction between at least one of the plurality of semiconductor regions and the first semiconductor layer. A depletion layer which is formed in the first semiconductor layer when a reverse bias voltage is applied to the at least one photodiode portion has a field intensity of about 0.3 V/&mgr;m or more.

Light sensitive element and light sensitive element having internal circuitry

A semiconductor device includes: a photosensitive section essentially composed of a PN junction between a semiconductor multilayer structure of the first conductivity type and a first semiconductor layer of the second conductivity type; and a partitioning portion for splitting the photosensitive section into a plurality of regions. The semiconductor multilayer structure of the first conductivity type includes: a semiconductor substrate of the first conductivity type; a first semiconductor layer of the first conductivity type; and a second semiconductor layer of the first conductivity type. The partitioning portion includes a third semiconductor layer of the first conductivity type extending from the first semiconductor layer of the second conductivity type so as to reach the second semiconductor layer of the first conductivity type.

Photosensitive device with internal circuitry that includes on the same substrate

A circuit-integrated light-receiving device of the present invention includes: a semiconductor substrate of a first conductivity type; a first semiconductor crystal growth layer of the first conductivity type provided on a surface of the semiconductor substrate, wherein the first semiconductor crystal growth layer includes a first portion whose impurity concentration gradually decreases in a direction away from the surface of the semiconductor substrate and a second portion located in a first region above the first portion whose impurity concentration distribution is uniform in a depth direction; a buried diffusion layer of the first conductivity type located in a second region which is above the first portion of the first semiconductor crystal growth layer and does not overlap the first region; a second semiconductor crystal growth layer of a second conductivity type which is provided across a surface of the first semiconductor crystal growth layer and a surface of the buried diffusion layer; and a separation diffusion region having the first conductivity type for dividing the second semiconductor crystal growth layer into a light-receiving device section and a signal processing circuit section. The first region is located in the light-receiving device section. In the signal processing circuit section, the buried diffusion layer is in contact with the first portion of the first semiconductor crystal growth layer.

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Kashiba, Japan

Isamu Ohkubo