Abstract: A CMOS image sensor includes a plurality of pixel regions formed under a front surface of a substrate, and having photodiodes separated from each other by a field oxide, a multi-layered metal interconnection formed over the pixel regions of the front of the substrate, a bump connected to an uppermost metal interconnection of the multi-layered metal interconnection, a plurality of trenches formed in a backside of the substrate, wherein the trenches have different depths for each wavelength of light, and correspond to the respective pixel regions, and a glass covering the backside of the substrate.

Abstract: An imager having superior separation properties is provided in which a visible image and an infrared image can be independently and simultaneously obtained. The above imager has a wavelength separation portion of separating an electromagnetic wave carrying an image into wavelengths, and image-taking portions detecting the visible image and the infrared image described above. In the imager described above, at least one of the image-taking portions has a detecting part which is optimized to detect a wavelength component which is to be detected.

Abstract: A pixel sensor cell includes a substrate of a first conductivity type, and a photoconversion region. The photoconversion region includes a pinning layer of the first conductivity type for receiving incident light of multiple colors, and a diode implant layer of a second conductivity type, disposed below the pinning layer, for accumulating photo-generated charge. Also included is a deep well of the first conductivity type, disposed below the diode implant layer, for rejecting at least one color of the incident light. The deep well includes a doped region, vertically disposed at a predetermined depth below the diode implant layer. The diode implant layer is effective in accumulating photo-generated charge of a blue color, and the deep well is effective in rejecting photo-generated charges of green and red colors from the diode implant layer.

Abstract: A method of fabricating light-sensing devices including photodiodes monolithically integrated with CMOS devices. Several types of photodiode devices (PIN, HIP) are expitaxially grown in one single step on active areas implanted in a common semiconductor substrate, the active areas having defined polarities. The expitaxially grown layers for the photodiode devices may be either undoped or in-situ doped with profiles suitable for their respective operation. With appropriate choice of substrate materials, device layers and heterojunction engineering and process architecture, it is possible to fabricate silicon-based and germanium-based multi-spectral sensors that can deliver pixel density and cost of fabrication comparable to the state of the art CCDs and CMOS image sensors. The method can be implemented with epitaxially deposited films on the following substrates: Silicon Bulk, Thick-Film and Thin-Film Silicon-On-Insulator (SOI), Germanium Bulk, Thick-Film and Thin-Film Geranium-On-Insulator (GeOI).

Abstract: A pixel including a substrate and a plurality of photoconductive layers sequentially deposited on and substantially parallel to the substrate and configured to receive incident electromagnetic radiation. Each photoconductive layer is configured to absorb a different wavelength range of the incident electromagnetic radiation and configured to provide an indication of an amount of incident electromagnetic radiation within the corresponding wavelength range absorbed by the layer based on a change in the conductance of the layer.

Abstract: There is provided a dye-containing resist composition comprising a ketol solvent; a negative type resist composition comprising a resin, a photoacid generator or a photobase generator, a crosslinking compound, a dye and a ketol solvent; a negative type resist composition comprising a resin, a photoradical generator, a crosslinking compound, a dye and a ketol solvent; a positive type resist composition comprising a resin, a photoacid generator, a crosslinking compound, a dye and a ketol solvent. The ketol is preferably ?-hydroxyketone, more preferably 4-hydroxy-4-methyl-2-pentanone. The resist composition does not occur problems such as occurrence of foreign matters (particles) even when the concentration of dye is increased, and enables the production of color filters in a shape of thinner film.

Abstract: Multiple devices that operate at different wavelengths of light are incorporated into a single composite assembly to reduce the amount of space that is needed to incorporate the assembly into a consumer electronics device. In addition, by implementing the devices in a single composite assembly, costs associated with manufacturing, assembly and shipping the assembly can be reduced. The composite assembly includes filtering mechanisms that prevent undesired wavelengths of light from impinging on the devices.

Abstract: Provided are embodiments of an image sensor. The image sensor can comprise a first substrate including a transistor circuit, a lower interconnection layer, an upper interconnection layer, and a second substrate including a vertical stacked photodiode. The lower interconnection layer is disposed on the first substrate and comprises a lower interconnection connected to the transistor circuit. The upper interconnection layer is disposed on the lower interconnection layer and comprises an upper interconnection connected with the lower interconnection. The vertical stacked photodiode can be disposed on the upper interconnection layer and connected with the upper interconnection through, for example, a single plug connecting a blue, green, and red photodiode of the vertical stack or a corresponding plug for each of the blue, green, and red photodiode of the vertical stack.

Abstract: An image sensor includes a semiconductor layer, and first and second photoelectric converting units including first and second impurity regions in the semiconductor layer that are spaced apart from each other and that are at about an equal depth in the semiconductor layer, each of the impurity regions including an upper region and a lower region. A width of the lower region of the first impurity region may be larger than a width of the lower region of the second impurity region, and widths of upper regions of the first and second impurity regions are equal.

Abstract: In an optical unit including a photoelectric conversion chip adapted to be optically connected to an optical fiber, and a semiconductor chip for driving the photoelectric conversion chip, both the photoelectric conversion chip and the semiconductor chip are wrapped with a flexible sheet, to thereby produce an enveloper enveloping the photoelectric conversion chip and the semiconductor chip therein. At least a part of the enveloper is formed as a transparent area for allowing an optical connection between the optical fiber and the photoelectric conversion chip.

Abstract: Provided are an image sensor and a manufacturing method thereof. The image sensor can include a first epitaxial layer with a first ion implantation layer, a second epitaxial layer with a second ion implantation layer, and a third epitaxial layer with a third ion implantation layer on a substrate. The first, second, and third ion implantation layers can provide a red, green, and blue photodiode, respectively. A trench can be formed in the third epitaxial layer on the third ion implantation layer to remove the damaged surface of the third epitaxial layer.

Abstract: A solid-state image capturing device having a plurality of light receiving sections for performing photoelectrical conversion on and capturing image light from a subject is provided. In the light receiving sections, a low concentration opposite conductivity layer is provided either on a single conductivity substrate or a single conductivity layer, a high concentration opposite conductivity layer having a higher impurity concentration than the low concentration opposite conductivity layer is provided on the low concentration opposite conductivity layer, and a photodiode is constituted by a PN junction of the single conductivity substrate or the single conductivity layer and the low concentration opposite conductivity layer.

Abstract: An image sensor and related method of fabrication are disclosed. The image sensor comprises a plurality of photoelectric conversion regions disposed in a predetermined field of a semiconductor substrate, color filters arranged on the photoelectric conversion regions, and a reflection protection structure disposed between the photoelectric conversion regions and the color filters. The reflection protection structure comprises portions having different thicknesses in relation to the color filters.

Abstract: An optical color sensor system is provided including providing a substrate having an optical sensor therein and forming a passivation layer over the substrate. The passivation layer is planarized and color filters are formed over the passivation layer. A planar transparent layer is formed over the color filters and microlenses are formed on the planar transparent layer over the color filters.

Abstract: Photomask patterns are represented using contours defined by level-set functions. Given target pattern, contours are optimized such that defined photomask, when used in photolithographic process, prints wafer pattern faithful to target pattern. Optimization utilizes “merit function” for encoding aspects of photolithographic process, preferences relating to resulting pattern (e.g. restriction to rectilinear patterns), robustness against process variations, as well as restrictions imposed relating to practical and economic manufacturability of photomasks.

Abstract: A method for photo-detecting and an apparatus for the same are provided. The apparatus for photo-detecting includes a first P-N diode and a second P-N diode. The first P-N diode, has a first P-N junction which has a first thickness, by which a first electrical signal is generated when irradiated by light, and the second P-N diode has a second P-N junction which has a second thickness, by which a second electrical signal is generated when irradiated by light. The second thickness is larger than the first thickness and an operation of the first electrical signal and the second electrical signal is proceeded for obtaining a third electrical signal.

Abstract: The invention is to suppress a loss in image quality resulting from a sensitivity difference among different colors and to suppress an increase in a chip area. The invention provides for example an image sensor including three light detecting element rows respectively having R, G and B color filters on light detecting apertures, in which the light detecting element in the G light detecting element row has a light detecting area larger than that of the light detecting element in other B and R light detecting element rows and centers of gravity of light detecting parts of the light detecting elements in the respective light detecting element rows are arranged with a constant pitch (pitch Q) among the light detecting element rows and in which the G light detecting element row with a larger light detecting area in the light detecting element is not positioned as an end row among the R, G and B light detecting element rows but as a central light detecting element row.

Abstract: Provided is a CMOS image sensor. The CMOS image sensor can include a semiconductor substrate, a blue photodiode region, a red photodiode region, a green photodiode region, an overcoat layer, and microlenses. The substrate can have a first photodiode region, a second photodiode region, and a transistor region. The blue photodiode region is formed having a predetermined depth in the first photodiode region. The red photodiode region is formed in the first photodiode region having a depth greater than that of the blue photodiode region with a gap separating the red photodiode region from the blue photodiode region. The green photodiode region is formed in the second photodiode region having a depth between the depths of the blue and red photodiode regions. The overcoat layer is formed on the semiconductor substrate, and microlenses are formed on the overcoat layer to correspond to the first and second photodiode regions.

Abstract: An optical color sensor system is provided including providing a substrate having an optical sensor therein and forming a passivation layer over the substrate. The passivation layer is planarized and color filters are formed over the passivation layer. A planar transparent layer is formed over the color filters and microlenses are formed on the planar transparent layer over the color filters.

Abstract: A photoreceiver cell with separation of color components of light incident to its surface, formed in a silicon substrate of the conductivity of the first type with an ohmic contact and comprising: the first, second and third regions, which have mutual positioning and configuration, which provide formation of the first and the second channels for diffusion of the secondary charge carriers generated in the substrate regions located under the first and the second potential barriers to the first and the third p-n junctions respectively; in this case, the length of the channels does not exceed the diffusion length of the secondary charge carriers. Some embodiments provide increased spatial resolution of the projected image and its dynamic range. Some embodiments provide small photo-cell area. Some embodiments are used in multielement photoreceivers for video cameras and digital cameras.

Abstract: A CMOS image sensor and a method for fabricating the same is disclosed, to enhance the image-sensing efficiency by forming a concave lens area for improving the light-condensing efficiency in a planarization layer formed before a micro-lens array, in which the CMOS image sensor includes a plurality of photosensitive devices on a semiconductor substrate; an insulating interlayer on the plurality of photosensitive devices; a plurality of color filter layers in correspondence with the respective photosensitive devices, to filter the light by respective wavelengths; a planarization layer on the color filter layers, and having first micro-lens by intaglio in correspondence with the respective photosensitive patterns to condense the light secondly; and a plurality of second micro-lens layers on the planarization layer in correspondence with the respective photosensitive devices, to condense the light firstly.

Abstract: Provided is a manufacturing method of a CMOS image sensor. The method includes forming an interlayer insulating layer, a color filter layer, and a planarizing layer. A first photoresist is applied on the planarizing layer, and patterning of the first photoresist is performed using a first mask to form a microlens pattern corresponding to photodiodes on a semiconductor substrate. The microlens pattern is reflowed to form dome-shaped microlenses. A second photoresist is applied on the resulting substrate, and patterning of the second photoresist is preformed using a second mask to retain the second photoresist on top portions of the microlenses. Edge portions of the microlenses are selectively removed using the patterned second photoresist as a mask to make CD (critical dimension) spaces between the microlenses uniform.

Abstract: A semiconductor photodetecting device is provided for enabling a solid-state image sensor to meet the requirements of higher quality imaging and more reduction in cost. The photodetecting device of the present invention includes: a semiconductor substrate; and an epitaxial layer formed on the semiconductor substrate by epitaxial growth. The epitaxial layer has a multilayer structure including: a first pn junction layer; a first insulating layer; a second pn junction layer; a second insulating layer; and a third pn junction layer. The first insulating layer and the second insulating layer have openings, and the first pn junction layer and the second pn junction layer are adjacent to each other through the openings of the first insulating layer which is placed in between these pn junction layers, and the second pn junction layer and the third pn junction layer are adjacent to each other through the openings of the second insulating layer which is placed in between these pn junction layers.

Abstract: A CMOS imaging device including a two pixel detection system for red, green, and blue light. One pixel detects red and blue light and another pixel detects green light. The detection of red and blue is based on wavelength and the device is structured such that in the red/blue pixel, detection of blue light is at a shallow substrate depth, while detection of red is at a deeper substrate depth. The pixel array is structured such that the red/blue pixel is adjacent to the green pixel and alternates between red/blue and green pixels. The invention is also related to methods of forming such an imager array and pixels.

Abstract: According to one embodiment of the present disclosure, a system for generating a reconstructed image generally includes a carrier substrate, a number of image sensors, and an image processing circuit. The image sensors are mounted on a surface of the carrier substrate. The image processing circuit is coupled to each of the image sensors and operable to receive a raw image from each of a plurality of image sensors and combine the raw image of each of the image sensors into the reconstructed image.

Abstract: A photoreceiver cell with separation of color components of light incident to its surface, formed in a silicon substrate of the conductivity of the first type with an ohmic contact and comprising: the first, second and third regions, which have mutual positioning and configuration, which provide formation of the first and the second channels for diffusion of the secondary charge carriers generated in the substrate regions located under the first and the second potential barriers to the first and the third p-n junctions respectively; in this case, the length of the channels does not exceed the diffusion length of the secondary charge carriers. A technical result of the present invention is an increase in spatial resolution of the projected image and its dynamic range. Another technical result of the present invention is a decrease in the photo-cell area. A photoreceiver cell with color separation may find broad application in multielement photoreceivers for video cameras and digital cameras.

Abstract: In a photoelectric converting film stack type solid-state image pickup device, a plurality of photoelectric converting film are stacked on a semiconductor substrate in which a signal readout circuit is formed, each of the photoelectric converting films is sandwiched between a common electrode film and pixel electrode films corresponding to respective pixels, and photo-charges generated in the photoelectric converting films are taken out through the pixel electrode films. In the solid-state image pickup device, a common electrode film for a first photoelectric converting film is used also as a common electrode film for a second photoelectric converting film, the first photoelectric converting film is stacked below the common electrode film, and the second photoelectric converting film is stacked above the common electrode film.

Abstract: A compound image sensor includes a plurality of PN junction layers connected in parallel. The PN junction layers have different band gap energies, each corresponding to the absorption of light of blue, green, and red colors. The image sensor further includes oxide layers deposited between the PN junction layers to insulate the PN junction layers.

Abstract: An image sensor includes a first photodiode formed in a semiconductor substrate at a depth reachable by red light, a second photodiode disposed on or over the first photodiode in the semiconductor substrate at a depth reachable by blue light, a third photodiode disposed adjacent to the second photodiode, a plug connected to the first photodiode, transistor structures on the semiconductor substrate and electrically connected with the first, second and third diodes, an insulating layer covering the transistor structures, and microlenses on the insulating layer.

Abstract: An image sensor including a first epitaxial layer having a first photodiode, a second epitaxial layer formed on and/or over the first epitaxial layer, the second epitaxial layer having a second photodiode and a first plug, and a third epitaxial layer formed on and/or over the second epitaxial layer, the third epitaxial layer having a third photodiode, a second plug and an isolation layer.

Abstract: An image sensor including a first epitaxial layer formed over a semiconductor substrate; first photodiodes formed spaced apart in the first epitaxial layer; a first isolation region electrically isolating the first photodiodes from each other; a second epitaxial layer formed over the first epitaxial layer; second photodiodes formed spaced apart in the second epitaxial layer; and a second isolation region electrically isolating the second photodiodes from each other.

Abstract: Polycrystalline silicon thin films are each fixed to the same potential and are each formed under the protective film of each of a plurality of pixel regions for receiving red light, a plurality of pixel regions for receiving green light, and a plurality of pixel regions for receiving blue light, and each polycrystalline silicon thin films has a different thickness for selectively transmitting a received light wavelength of each of the plurality of pixel regions for receiving red light, the plurality of pixel regions for receiving green light, and the plurality of pixel regions for receiving blue light to function as a color filter. The color filter can be formed during an IC manufacturing process while the color filter is positioned to align with the pixel region serving as a light receiving element, with higher precision.

Abstract: A method of fabricating a CMOS image sensor is provided, in which a trapezoidal microlens pattern profile is formed to facilitate reflowing the microlens pattern and by which a curvature of the microlens may be enhanced to raise its light-condensing efficiency. The method includes forming a plurality of photodiodes on a semiconductor substrate; forming an insulating interlayer on the semiconductor substrate including the photodiodes; forming a protective layer on the insulating interlayer; forming a plurality of color filters corresponding to the photodiodes; forming a top coating layer on the color filters; forming a microlens pattern on the top coating layer; and forming a plurality of microlenses by reflowing the microlens pattern.

Abstract: A Complementary Metal Oxide Semiconductor (CMOS) image sensor includes a red photodiode formed in an first epitaxial layer, an isolation layer formed with a contact region left in a partial area of the red photodiode, a green photodiode formed in a surface of the isolation layer, a contact formed in the contact region at a predetermined spatial distance from the green photodiode, a second epitaxial layer formed on the first epitaxial layer in which the green photodiode is formed, a plurality of plugs formed in the second epitaxial layer and electrically connected to the green photodiode and the contact, a device isolation film formed in a surface of the second epitaxial layer, a blue photodiode formed in a surface of the second epitaxial layer above the green photodiode, and a well region formed in the second epitaxial layer inside the plug.

Abstract: A photodiode that can separately detect the intensities of the three wavelength ranges of ultraviolet light of 400 nm or below includes an insulating layer; and a plurality of silicon semiconductor layers having different thicknesses formed on the insulating layer, wherein each of the plurality of silicon semiconductor layers has a low-concentration diffusion layer formed by diffusing one of a P-type impurity or an N-type impurity therein with a low concentration; a P-type high-concentration diffusion layer formed by diffusing a P-type impurity therein with a high concentration; and an N-type high-concentration diffusion layer formed by diffusing an N-type impurity therein with a high concentration, and wherein the P-type high-concentration diffusion layer and the N-type high-concentration diffusion layer formed in a respective one of the plurality of silicon semiconductor layers are arranged to face each other with the low-concentration diffusion layer interposed there between.

Abstract: A solid-state image sensing device provided with photoelectric conversion films stacked above a semiconductor substrate, comprising: first impurity regions as defined herein; second impurity regions as defined herein; signal charge reading regions as defined herein; and third impurity regions as defined herein.

Abstract: A solid state image pickup device includes: a first area defined on a principal surface of a semiconductor substrate; a second area defined in an area adjacent to the first area along a first direction; and a third area defined in an area adjacent to the second area along the first direction, wherein the first area includes: a plurality of photoelectric conversion elements; and a plurality of vertical transfer channels formed adjacent to the plurality of photoelectric conversion elements; the second area includes: a horizontal transfer channel; and a floating diffusion region and a first stage drive FET of an amplifier; and the third area includes: a first state load FET, a second stage drive FET, a second stage load FET, a third stage drive FET and a third stage load FET, respectively of the amplifier. The solid state image pickup device can be made compact.

Abstract: An image sensor is provided. The image sensor includes a plurality of photodiode doped regions in a substrate, a passivation layer above the substrate, a dielectric layer between the passivation layer and the substrate, and a plurality of color filters in the dielectric layer being corresponding to the photodiode doped regions.

Abstract: An imaging sensor includes a signal processing section, a photo-current generating and collecting section, and a separating region between the signal processing section and the photo-current generating and collecting section. The photo-current generating and collecting section includes a photodiode well having a first type of conductivity, and a contact associated with the photodiode well. A region surrounds the photodiode well, and is adjacent the separating region and has a second type of conductivity.

Abstract: A solid-state image pickup device comprising a semiconductor substrate, and a plurality of photoelectric conversion elements arranged on a surface of said semiconductor substrate both in a line direction and in a column direction perpendicular to the line direction to form a tetragonal lattice, wherein: said photoelectric conversion elements include a plurality of high-sensitive photoelectric conversion elements for performing photoelectric conversion in relatively high sensitivity, and a plurality of low-sensitive photoelectric conversion elements for performing photoelectric conversion in relatively low sensitivity; and said plurality of high-sensitive photoelectric conversion elements and said plurality of low-sensitive photoelectric conversion elements are arranged so as to be shaped like a checkered pattern.

Abstract: The invention concerns a matrix structure of multispectral detectors (200) comprising: a superimposition of several layers of semiconductor material separated by layers of dielectric material transparent to a light to be detected, said superimposition offering a face for receiving the light to be detected, said superimposition of layers of semiconductor material being spread out in picture elements or pixels, each part of the layer of semiconductor material corresponding to a pixel comprising a light detection element delivering electrical charges in response to the light received by said detection element, means for collecting the electrical charges delivered by each light detection element, said collection means being electrically connected to electrical connection means (153) and comprising conductive walls (151).

Abstract: A color sensor includes: a substrate; first to third light receiving elements on the substrate; a red light filter for passing a red light and a first near infrared light block filter for blocking a near infrared light on the first light receiving element; a green light filter for passing a green light and a second near infrared light block filter on the second light receiving element; a visible light block filter for blocking a visible light on the third receiving element; and an ultraviolet light block plate disposed over the first and second near infrared light block filters and the visible light block filter.

Abstract: An image sensor capable of preventing the cross-talk phenomenon due to a deep penetration depth and a low absorption coefficient of red light in a photodiode region and a method for fabricating the same, wherein the photodiode for collecting incident light has different depths in accordance with the wavelength of the incident light. The photodiode for receiving red light, which has the longest wavelength, has the deepest depth, the photodiode for receiving blue light has the least depth, and the photodiode for receiving green light, which has a wavelength between the red light and the blue light has an intermediate depth.

Abstract: A recessed color filter array using patterned metal as an etch stop and a method of forming the same. In one embodiment, at least one metal etch stop is formed in a semiconductor dielectric layer at the same time as the formation of one or more layers of metal interconnect elements, thereby reducing the number of necessary process steps and reducing costs. The etch stop may be formed at any layer where other metal elements are present.

Abstract: An array of vertical color filter (VCF) sensor groups, optionally including or coupled to circuitry for converting photogenerated carriers produced in the sensors to electrical signals, and methods for reading out any embodiment of the array. The array has a top layer (including the top sensors of the sensor group) and at least one low layer including other ones of the sensors. Only the top layer can be read out with full resolution. Each low layer can only be read out with less than full resolution to generate fewer sensor output values than the total number of pixel sensor locations. Typically, the sensor groups are arranged in cells, each cell including a S sensor groups (e.g., S=4), with S sensors in the top layer and fewer than S sensors in each low layer of the cell. Typically, each cell includes at least one shared sensor (a sensor shared by two or more VCF sensor groups) in each low layer, and each cell includes sensor selection switches (e.g., transistors) between the cell's sensors and a sense node.

Abstract: The invention is to suppress a loss in image quality resulting from a sensitivity difference among different colors and to suppress an increase in a chip area. The invention provides for example an image sensor including three light detecting element rows respectively having R, G and B color filters on light detecting apertures, in which the light detecting element in the G light detecting element row has a light detecting area larger than that of the light detecting element in other B and R light detecting element rows and centers of gravity of light detecting parts of the light detecting elements in the respective light detecting element rows are arranged with a constant pitch (pitch Q) among the light detecting element rows and in which the G light detecting element row with a larger light detecting area in the light detecting element is not positioned as an end row among the R, G and B light detecting element rows but as a central light detecting element row.

Abstract: A photoelectric conversion element comprises a photoelectric conversion section that includes: a pair of electrodes; and a photoelectric conversion layer disposed between the pair of electrodes, wherein the photoelectric conversion section further comprises between one of the pair of electrodes and the photoelectric conversion layer a first charge-blocking layer that restrains injection of charges from the one of the electrodes into the photoelectric conversion layer when a voltage is applied to the pair of electrodes, and the first charge-blocking layer comprises a plurality of layers.

Abstract: A method for fabricating a color filter is disclosed. First, a substrate having a dielectric layer and a passivation thereon is provided. Next, a first pattern transfer process is performed to form a trench in the dielectric layer and the passivation layer, and a color filter is formed in the trench, in which the color filter partially covers the surface of the passivation layer. Next, a chemical mechanical polishing process is performed to planarize the color filter, such that the surface of the color filter is even with the surface of the passivation layer.

Abstract: A charge-coupled device includes a photosensitive region for collecting charge in response to incident light; a first and third gate electrode made of a transmissive material spanning at least a portion of the photosensitive region; and a second gate electrode made of a transmissive material that is less transmissive than the first and third gates and spans at least a portion of the photosensitive region; wherein the first, second and third gates are arranged symmetrically within an area that spans the photosensitive region.

Abstract: A semiconductor light receiving device is disclosed which is capable of receiving a first wavelength band light beam and a second wavelength band light beam having a shorter wavelength than that of the first wavelength band light beam. The device has a light absorbing layer of a first conductivity type formed on a semiconductor surface region of the semiconductor substrate the light absorbing layer absorbs the first and second wavelength band light beams. A cap layer of the first conductivity type is formed on the light absorbing layer. In the cap layer, a region of a second conductivity type is formed which transmits the second wavelength band light beam. A light collecting layer is formed on the semiconductor surface region and adjacently to the cap layer and the light absorbing layer. The light collecting layer has a convex shape with curvature to collect the second wavelength band light beam.