WO2023108857A1 - 光电探测器 - Google Patents
光电探测器 Download PDFInfo
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- WO2023108857A1 WO2023108857A1 PCT/CN2022/072641 CN2022072641W WO2023108857A1 WO 2023108857 A1 WO2023108857 A1 WO 2023108857A1 CN 2022072641 W CN2022072641 W CN 2022072641W WO 2023108857 A1 WO2023108857 A1 WO 2023108857A1
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- limiting structure
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
- H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
- H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
- H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier
- H01L31/105—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the PIN type
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0224—Electrodes
- H01L31/022408—Electrodes for devices characterised by at least one potential jump barrier or surface barrier
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0232—Optical elements or arrangements associated with the device
- H01L31/02327—Optical elements or arrangements associated with the device the optical elements being integrated or being directly associated to the device, e.g. back reflectors
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present disclosure relates to the technical field of semiconductors, and in particular, to a photodetector.
- Photonic chips with LSI-like advantages. Photonic chips have the characteristics of low cost, small size, low power consumption, flexible expansion and high reliability. At present, silicon-based photonic chips are considered by the industry to be the most promising photonic chips. Silicon-based photonic chips can combine microelectronics and optoelectronics, give full play to the advantages of advanced and mature process technology, high integration, and low cost of silicon-based microelectronics, and have broad market prospects.
- Silicon-based photonic chips usually use silicon-on-insulator (Si1icon On Insulator, SOI) materials to form optical waveguides.
- SOI silicon-on-insulator
- the optical waveguide is formed by Si core layer and SiO 2 cladding layer.
- the strong confinement effect can realize the waveguide bending radius as small as micron, thus providing the basis for the miniaturization and high-density integration of silicon-based photonic chips.
- photodetectors are often used at the receiving end of silicon-based photonic chips, such as germanium-silicon waveguide photodetectors.
- the silicon germanium waveguide photodetector is a device that converts high-speed optical signals into current signals, and is a key device for silicon-based photonic chips.
- the germanium-silicon waveguide photodetector mainly relies on the absorption of light by the germanium material to generate photocurrent. In related technologies, it is necessary to further improve the responsivity of the photodetector while taking into account the bandwidth of the photodetector.
- the absorption structure is at least partly located on the light confinement structure; the coupled light is confined in the absorption structure for circular transmission through the total reflection of the side wall of the absorption structure, and the coupled light is converted into electrons and holes;
- the flat plate structure surrounds the waveguide structure and the light confinement structure
- the first electrode structure is located inside the light-limiting structure; the second electrode structure is located outside the light-limiting structure and is in contact with the light-limiting structure; the first electrode structure and the second electrode structure are used to collect Electrons or holes transported along the absorbing structure and the light-limiting structure; the types of carriers collected by the first electrode structure and the second electrode structure are different.
- the light confinement structure includes a first doped region and a second doped region surrounding the first doped region; wherein, the first doped region and the second doped region are doped type opposite;
- the first electrode structure is located inside the first doped region and is in contact with the first doped region, and the first electrode structure is used to collect energy transported along the absorption structure and the first doped region. electrons or holes;
- the photodetector further includes an intrinsic region located between the first doped region and the second doped region, wherein,
- the material of the intrinsic region is the same as that of the light-limiting structure
- the material of the intrinsic region is the same as the material of the absorbent structure.
- the photodetector further includes a first intrinsic region, a second intrinsic region and a second Intrinsic region, where,
- the material of the first intrinsic region is the same as that of the light-limiting structure; the material of the second intrinsic region is the same as that of the absorption structure.
- the sum of the projections of the first doped region, the intrinsic region and the second doped region on the preset plane covers the projection of the absorbing structure on the preset plane;
- the projection of the structure on the preset plane covers the projection of the intrinsic region on the preset plane;
- the predetermined plane is perpendicular to the thickness direction of the light-limiting structure.
- the first electrode structure includes a first electrode, a first electrode contact region, and a third doped region; wherein, the third doped region is located inside the first doped region and is connected to the first doped region.
- a doped region contact; the first electrode contact region is located on the surface of the third doped region and a region at a certain depth downward, and the first electrode is located above the first electrode contact region; the first The electrodes are used to collect electrons or holes sequentially transported along the absorption structure, the first doped region, the third doped region and the first electrode contact region;
- the second electrode structure includes a second electrode, a second electrode contact region, and a fourth doped region; wherein, the fourth doped region surrounds the light-limiting structure, and the second electrode contact region is located on the first electrode.
- the surface of the four-doped region and the area at a certain depth downwards, the second electrode is located above the second electrode contact region; the second electrode is used to collect sequentially along the absorption structure, the second doped region and the electrons or holes transported by the fourth doped region.
- the doping concentration of the second doping region is less than or equal to the doping concentration of the fourth doping region, and the doping concentration of the fourth doping region is lower than the doping concentration of the second electrode contact region.
- impurity concentration; the doping concentration of the first doping region is less than or equal to the doping concentration of the third doping region, and the concentration of the third doping region is less than the doping concentration of the first electrode contact region.
- the first electrode contact region is far away from the absorption structure, and the thickness of the third doped region is less than or equal to the thickness of the light confinement structure; the thickness of the waveguide structure is the same as that of the light confinement structure Same thickness.
- the shape of the projection of the waveguide structure on the preset plane includes a strip shape
- the third side wall is a side wall where the incident light is reflected for the first time after entering the light-limiting structure.
- the shape of the projection of the outer wall of the light-limiting structure on the preset plane includes one of the following:
- the incident light enters the light confinement structure tangentially to the second side where the second side wall of the light confinement structure is located through the waveguide structure, and couples the incident light to the light confinement structure through the light confinement structure.
- absorbed by the absorbing structure the sides where the outer walls of the light-limiting structure and the absorbing structure are located adopt, for example, circular, optimized deformation-like circular or polygonal structures.
- the light-limiting structure and the absorbing structure are excited to high-order modes during propagation, so that light leakage can be reduced, thereby improving the responsivity of the photodetector.
- the incident light cannot escape from the light-confining structure in the first direction due to the total reflection of the side walls in the light-confining structure, and finally all of it is coupled into the absorbing structure, and in the absorbing structure, due to the total reflection of the side walls
- the incident light will be confined in the absorbing structure, that is, the incident light propagates circularly in the light confining structure and the absorbing structure until it is completely absorbed, and the circular propagation can reduce the size requirements of the light confining structure and the absorbing structure, that is, it can reduce
- the photodetector size is required, and a smaller photodetector size can bring smaller photodetector parasitic parameters, so that the photodetector has a higher bandwidth.
- the photodetector provided by the embodiments of the present disclosure can take into account both high bandwidth and high responsivity.
- FIG. 1 is a schematic top view of a photodetector provided by an embodiment of the present disclosure
- FIG. 2 is a schematic top view of another photodetector provided by an embodiment of the present disclosure.
- Fig. 4 is a cross-sectional view along the B1-B1 direction in Fig. 1 and Fig. 2 .
- orientations or positional relationships indicated by the terms “length”, “width”, “depth”, “upper”, “lower”, “outer” etc. are based on those shown in the accompanying drawings.
- the orientation or positional relationship is only for the convenience of describing the present disclosure and simplifying the description, and does not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as limiting the present disclosure.
- the term "substrate” refers to a material on which subsequent layers of material are added.
- the substrate itself can be patterned.
- the material added on top of the substrate may be patterned or may remain unpatterned.
- the substrate may include various semiconductor materials, such as silicon, germanium, arsenide, indium phosphide, and the like.
- the substrate can be made of a non-conductive material such as glass, plastic or a sapphire wafer.
- the term "layer" refers to a portion of material comprising a region having a thickness.
- a layer may extend over the entirety of the underlying or overlying structure, or may have an extent that is less than the extent of the underlying or overlying structure.
- a layer may be a region of a homogeneous or heterogeneous continuous structure with a thickness less than that of the continuous structure.
- a layer may be located between the top and bottom surfaces of the continuous structure, or a layer may be between any horizontal faces at the top and bottom surfaces of the continuous structure.
- Layers may extend horizontally, vertically and/or along sloped surfaces.
- Layers can include multiple sublayers.
- an interconnect layer may include one or more conductor and contact sublayers (in which interconnect lines and/or via contacts are formed), and one or more dielectric sublayers.
- the silicon germanium waveguide photodetector generally adopts a square structure, and the light enters from one end of the light-limiting structure, exits from the corresponding other end, and undergoes one-way absorption.
- the size of the photodetector needs to be increased to obtain a larger responsivity;
- the size of the photodetector increases, the Increase the parasitic parameters of the photodetector, so that the photoelectric bandwidth of the photodetector decreases. That is to say, there is a mutually restrictive relationship between the responsivity of photodetectors and the photoelectric bandwidth.
- the germanium-silicon waveguide photodetector requires metal electrodes to be in contact with germanium and doped with germanium to form a P-I-N junction.
- the metal contact will affect the light absorption of germanium, causing light loss in the germanium absorption region, resulting in a decrease in the responsivity of the germanium-silicon waveguide photodetector.
- embodiments of the present disclosure aim to provide a photodetector with both high responsivity and high bandwidth.
- the incident light enters the light confinement structure tangentially to the second side where the second side wall of the light confinement structure is located through the waveguide structure, and the incident light is coupled to the absorbing structure through the light confinement structure. structure is absorbed.
- the sides where the outer walls of the light-limiting structure and the absorbing structure are located adopt, for example, circular, optimized deformation-like circular or polygonal structures.
- the light-limiting structure and the absorbing structure are excited to high-order modes during propagation, so that light leakage can be reduced, thereby improving the responsivity of the photodetector.
- the incident light cannot escape from the light-confining structure in the first direction due to the total reflection of the side walls in the light-confining structure, and finally all of it is coupled into the absorbing structure, and in the absorbing structure, due to the total reflection of the side walls
- the incident light will be confined in the absorbing structure, that is, the incident light propagates circularly in the light confining structure and the absorbing structure until it is completely absorbed, and the circular propagation can reduce the size requirements of the light confining structure and the absorbing structure, that is, it can reduce
- the photodetector size is required, and a smaller photodetector size can bring smaller photodetector parasitic parameters, so that the photodetector has a higher bandwidth.
- An embodiment of the present disclosure provides a photodetector, including: a flat plate structure, a waveguide structure, a light-limiting structure, an absorption structure, a first electrode structure, and a second electrode structure; wherein,
- the waveguide structure extends into the light confinement structure, and the first side where the first sidewall of the waveguide structure is located is tangent to the second side where the second sidewall of the outer sidewalls of the light confinement structure is located ;
- the waveguide structure is used to guide incident light into the light-limiting structure in a direction tangential to the second side;
- the absorption structure is at least partly located on the light confinement structure; the coupled light is confined in the absorption structure for circular transmission through the total reflection of the side wall of the absorption structure, and the coupled light is converted into electrons and holes;
- the flat plate structure surrounds the waveguide structure and the light confinement structure
- the first electrode structure is located inside the light-limiting structure; the second electrode structure is located outside the light-limiting structure and is in contact with the light-limiting structure; the first electrode structure and the second electrode structure are used to collect Electrons or holes transported along the absorbing structure and the light-limiting structure; the types of carriers collected by the first electrode structure and the second electrode structure are different.
- FIG. 1 is a schematic top view of a photodetector provided by an embodiment of the present disclosure
- FIG. 2 is a schematic top view of another photodetector provided by an embodiment of the present disclosure.
- the structures of the photodetectors shown in FIG. 1 and FIG. 2 are similar, and the difference mainly lies in the projected shapes of the light-limiting structure 2 and the absorbing structure 3 on a predetermined plane.
- the photodetector will be exemplarily described below according to FIG. 1 .
- the photodetector includes a flat plate structure 1, a waveguide structure 6, a light limiting structure 2, an absorption structure 3, a first electrode structure 4 and a second electrode structure 5; wherein the waveguide structure 6 extends to In the light limiting structure 2, the first side where the first sidewall of the waveguide structure 6 is located is tangent to the second side where the second sidewall of the outer sidewall of the light limiting structure 2 is located;
- the waveguide structure 6 is used to guide the incident light into the light confinement structure 2 in a direction tangent to the second side;
- the introduced light is confined in the light confinement structure by the total reflection of the side wall of the light confinement structure 2 2 for circular transmission, and couple the imported light into the absorption structure through the light-limiting structure 2;
- the absorption structure 3 is located on the light-limiting structure 2;
- the coupled light is coupled through the total reflection of the side wall of the absorption structure 3 Confined in the absorption structure 3 for circular transmission, and converts the coupled light into electrons and holes;
- the waveguide structure 6 is used to propagate incident light, and the incident light enters the light-limiting structure through the waveguide structure 6 .
- the waveguide structure 6 may be a silicon waveguide, and the silicon waveguide includes a silicon (Si) core layer and a silicon dioxide (SiO 2 ) cladding layer.
- the waveguide structure 6 extends into the light confinement structure 2, and the first side where the first sidewall of the waveguide structure 6 is located is the same as the second side where the second sidewall of the light confinement structure 2 is located.
- Tangential the waveguide structure 6 is used to guide incident light into the light-limiting structure 2 in a direction tangential to the second side.
- the incident light can be introduced into the light confinement structure 2 in a direction tangential to the outer wall of the light confinement structure 2, reducing the incidence of the incident light between the waveguide structure 6 and the confinement structure.
- the sudden change in the propagation process in the optical structure 2 reduces the high-order modes excited by the light during the propagation process, improves the stability of the incident light during the propagation process, reduces the light leakage, and improves the responsivity of the photodetector.
- the thickness of the flat plate structure 1 is smaller than the thickness of the waveguide structure 6; the flat plate structure 1 and the waveguide structure 6 form a ridge-shaped incident waveguide, and the incident waveguide is a silicon waveguide.
- the incident light enters the light confinement structure 2 through the incident waveguide and is coupled into the absorption structure 3 .
- the specific structure of the incident waveguide is not limited.
- photodetectors in embodiments of the present disclosure may include ridge-shaped incident waveguides as well as waveguides of other shapes.
- only a SiGe waveguide photodetector with a ridge-shaped incident waveguide is used as an example to describe the solutions provided by the embodiments of the present disclosure.
- the light confinement structure 2 is used to receive the incident light propagated by the incident waveguide and confine the introduced light in the coupling structure in the first direction through the total reflection of the side wall for circular transmission, and at the same time The light is coupled into the absorbing structure 3 through the light confinement structure.
- the material of the light confinement structure 2 may include lightly doped silicon.
- the incident light is confined in the coupling structure in the first direction by the total reflection effect of the sidewall of the light limiting structure 2 for circular transmission, and at the same time, all of the incident light is coupled into the absorbing structure 3 through the light limiting structure 2, It is then completely absorbed by said absorbent structure 3 .
- the light confining structure 2 couples all the imported light into the absorbing structure 3. It can be understood that the light entering the light confining structure 2 can be 100% coupled into the absorbing structure 3 from a theoretical design.
- the first direction is perpendicular to the stacking direction. It can be understood that, when the light limiting structure 2 and the absorbing structure 3 are vertically stacked, the first direction is a horizontal direction.
- the absorption structure 3 is located on the light confinement structure 2, and is used to confine the coupled light in the first direction in the absorption structure 3 through the total reflection of the side wall for circular transmission and convert the coupled light for electrons and holes.
- the absorber structure 3 may comprise a germanium absorber region.
- the flat plate structure 1 surrounds the waveguide structure 6 and the light limiting structure 2 ; the thickness of the flat plate structure 1 is smaller than the thickness of the light limiting structure 2 . It can be understood that the flat plate structure 1 and the light limiting structure 2 form a ridge waveguide structure.
- the first electrode structure 4 is located inside the light-limiting structure 2 and is in contact with the light-limiting structure 2; the second electrode structure 5 is located in the flat plate structure 1 and the second electrode structure 5 surrounds the light-limiting structure 2; the first electrode structure 4 and the second electrode structure 5 are used to collect electrons or holes transmitted along the absorption structure 3 and the light-limiting structure 2; the first electrode
- the types of carriers collected by the structure 4 and the second electrode structure 5 are different. For example, electron-hole pairs generated by photons move toward the two poles under the action of an external electric field. When the carriers collected by the first electrode structure 4 are electrons, the carriers collected by the second electrode structure 5 are holes; or when the carriers collected by the first electrode structure 4 are holes, the carriers collected by the second electrode structure 5 are electrons.
- the first electrode structure 4 and the second electrode structure 5 include metal electrodes.
- the first electrode structure 4 is located inside the light-limiting structure 2 and is in contact with the light-limiting structure 2, thereby avoiding the contact between the germanium absorption region and the metal electrode, reducing the optical absorption of the metal electrode, and further improving the responsivity .
- no ohmic contact between germanium and metal is required, and the process is simple and the cost is low.
- Fig. 3a and Fig. 3b are cross-sectional views along A1-A1 direction in Fig. 1 and Fig. 2 .
- the light confinement structure 2 includes a first doped region 2-1 and a second doped region 2-1 surrounding the first doped region 2-1.
- the doping type of the first doped region 2-1 is opposite to that of the second doped region 2-3;
- the first electrode structure 4 is located inside the first doped region 2-1 and In contact with the first doped region 2-1, the first electrode structure 4 is used to collect electrons or holes transported along the absorption structure 3 and the first doped region 2-1;
- the two-electrode structure 5 is used to collect electrons or holes transported along the absorption structure 3 and the second doped region 2-3.
- both the first doped region 2 - 1 and the second doped region 2 - 3 include a ring waveguide structure.
- the doping types of the ring waveguide structure in the first doped region 2 - 1 and the ring waveguide structure in the second doped region 2 - 3 are opposite.
- the projections of the first doped region 2 - 1 ring waveguide structure and the second doped region 2 - 3 ring waveguide structure on a preset plane both include circular rings.
- the projections of the first doped region 2-1 ring waveguide structure and the second doped region 2-3 ring waveguide structure on a preset plane include deformed circular rings or positive Closed graphics such as polygonal rings.
- the photodetector further includes an intrinsic region 2-2 located between the first doped region 2-1 and the second doped region 2-3. , wherein, the material of the intrinsic region 2-2 is the same as that of the light confinement structure 2; or, the material of the intrinsic region 2-2 is the same as the material of the absorption structure 3.
- the intrinsic region 2-2 includes a ring waveguide structure.
- the light confinement structure 2 includes the first doped region 2-1 ring waveguide structure, the intrinsic region 2-2 A ring waveguide structure and a second doped region 2-3 ring waveguide structure; when the material of the intrinsic region 2-2 is the same as that of the absorption structure 3, the absorption structure 3 also includes the intrinsic region 2- 2 ring waveguide structure.
- the inner side of the ring waveguide structure in the second doped region 2-3 coincides with the outer side of the ring waveguide structure in the intrinsic region 2-2
- the inner side of the ring waveguide structure in the intrinsic region 2-2 coincides with the outer side of the ring waveguide structure in the intrinsic region 2-2.
- the outer sides of the first doped region 2-1 ring waveguide structure overlap.
- the intrinsic region 2-2 between the first doped region 2-1 and the second doped region 2-3 increases the electric field intensity in the absorbing structure 3 so as to increase the carrier
- the flow velocity of the photodetector increases the bandwidth of the detector; in addition, in the design process of the photodetector, by adjusting the width of the intrinsic region 2-2, a greater degree of freedom can be provided for the size design of the photodetector.
- the photodetector further includes a light-limiting structure 2 located between the first doped region 2-1 and the second doped region 2-3.
- a first intrinsic region 2-2A and a second intrinsic region 2-2B are stacked in sequence in the direction of thickness, wherein the material of the first intrinsic region 2-2A is the same as that of the light-limiting structure 2;
- the material of the second intrinsic region 2 - 2B is the same as that of the absorption structure 3 . That is to say, the light limiting structure 2 also includes the first intrinsic region 2-2A; the absorption structure 3 further includes the second intrinsic region 2-2B.
- the sum of the projections of the first doped region 2-1, the intrinsic region 2-2 and the second doped region 2-3 on a preset plane covers the absorption structure 3 Projection on the preset plane; the projection of the absorbent structure 3 on the preset plane covers the projection of the intrinsic region 2-2 on the preset plane; wherein, the preset plane is perpendicular to the preset plane The direction of the thickness of the light-limiting structure 2 is described.
- the sum of the projections of the first doped region 2-1, the intrinsic region 2-2 and the second doped region 2-3 on a preset plane has an area larger than that of the absorption structure
- the area of the projection of 3 on the preset plane can better provide a growth platform for the absorption structure 3; the projection of the absorption structure 3 on the preset plane covers the intrinsic region 2-2 in the preset Set the projection of the plane.
- the projection of the second electrode 5 - 1 on the preset plane is annular and away from the light limiting structure 2 .
- the specific shapes of the first electrode 4 - 1 and the second electrode 5 - 1 vary according to the shape of the electrode contact area, and are not limited to specific embodiments of the present disclosure.
- the doping concentration of the first electrode contact region 4-2 may be higher than that of the third doping region 4-3, and the doping concentration of the second electrode contact region 5-2 may be higher than that of the third doping region 4-3.
- the doping concentration of the four doped regions 5-3 is to reduce the resistance of the first electrode contact region 4-2 and the second electrode contact region 5-2, so that the electrodes and the electrode contact regions form good ohmic contacts, further improving the photoelectricity.
- the bandwidth of the detector is to reduce the resistance of the first electrode contact region 4-2 and the second electrode contact region 5-2, so that the electrodes and the electrode contact regions form good ohmic contacts, further improving the photoelectricity.
- the doping concentration of the second doping region 2-3 is less than or equal to the doping concentration of the fourth doping region 5-3; the doping concentration of the first doping region 2-1 The concentration is less than or equal to the doping concentration of the third doping region 4-3.
- the doping concentration of the second doped region 2-3 located in the light confinement structure 2 is less than or equal to that of the fourth doped region 5-3.
- Doping concentration; at the same time, the doping concentration of the first doping region 2-1 located in the light confinement structure 2 is less than or equal to the doping concentration of the third doping region 4-3.
- the shape of the projection of the waveguide structure 6 on the preset plane includes a strip shape; the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane includes at least a straight line and/or Or at least a closed figure formed by a curve, and the angle formed by the second side where the second side wall is located in the outer side wall of the light-limiting structure 2 and the third side where the third side wall is located in the outer side wall is an obtuse angle; wherein , the third side wall is the side wall where the incident light is reflected for the first time after entering the light-limiting structure 2 .
- the first side where the first sidewall of the waveguide structure 6 is located is tangent to the straight line;
- the first side where the first sidewall of the waveguide structure 6 is located is tangent to the curve.
- the reflection angle at the first reflection is not equal to 0 degrees. That is to say, after the incident light enters the light-limiting structure, it will not be directly reflected back from the entrance of the incident light, thereby preventing light from leaking from the entrance of the incident light.
- the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane includes one of the following:
- the light-limiting structure 2 further includes an inner sidewall.
- the projection shape of the inner wall of the light limiting structure 2 on the preset plane may be the same as or different from the projection shape of the outer wall of the light limiting structure 2 on the preset plane.
- the shape of the projection of the outer wall of the light limiting structure 2 on the preset plane may be a circle Shape, also can be polygonal or other shapes; For a circular shape.
- the projection of the light-limiting structure 2 on the preset plane may include one circular ring or multiple concentric circular rings.
- the projection of the outer wall and the inner wall of the light limiting structure 2 on the preset plane includes many different shapes.
- the outer wall of the light limiting structure 2 will be used in the preset
- the shape of the projection of the plane is taken as an example to illustrate different shapes of the projection of the light-limiting structure 2 on the preset plane.
- the projection shape of the inner wall of the light-limiting structure 2 on the preset plane is the same as that of the outer wall, which will not be repeated here.
- the projection shape of the outer wall of the light-limiting structure 2 on the preset plane is circular.
- the waveguide structure 6 extends into the light confinement structure 2 , and the first edge where the first sidewall of the waveguide structure 6 is located is tangent to the circular edge of the light confinement structure 2 . It can be understood that when the shape of the projection of the outer wall and the inner wall of the light limiting structure 2 on the preset plane is circular, the shape of the projection of the light limiting structure 2 on the preset plane For a circular shape.
- the incident light propagates circularly in the annular light confinement structure 2, so the size of the photodetector can be reduced, thereby reducing the parasitic parameters of the photodetector, so that the photodetector has a higher bandwidth.
- the preset plane is perpendicular to the thickness direction of the light-limiting structure, and the plane where the flat plate structure 1 is located is parallel to the preset plane.
- the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane is a closed shape formed by connecting multiple sections of curves.
- the waveguide structure 6 extends into the light-limiting structure 2, and the first side where the first sidewall of the waveguide structure 6 is located is tangent to one of the multiple curves, and one of the curves is at The radius of curvature at the point of tangency approaches infinity.
- each section of curves in the multi-section curves includes the same first sub-curve and second sub-curve; the radius of curvature of the first sub-curve approaches infinity at the first end point and the first sub-curve The radius of curvature of the curve gradually decreases from the first end point to the second end point connected to the second sub-curve.
- the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane is a closed shape formed by connecting four identical curves.
- the bending angle of the curve is 90 degrees, and each section of the curve is divided into two identical sub-curves by a 45-degree bisector.
- the radius of curvature of any section of the sub-curve gradually decreases when approaching the 45-degree bisector from the sub-curve end point away from the 45-degree bisector, and the curvature radius decreases to a certain value when reaching the 45-degree bisector. value.
- the radius of curvature of the projected shape of the light-limiting structure 2 on the preset plane changes gradually, thereby avoiding the generation of more high-order modes when light propagates in the light-limiting structure 2 , which is beneficial to reducing light leakage.
- the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane is a closed shape formed by connecting four identical curves.
- the bending angle of the curve is 90 degrees, and the curve has a 45 degree bisector.
- each section of the curve is sequentially divided into a third sub-curve, a fourth sub-curve and a fifth sub-curve from the first end point to the second end point, and the third sub-curve and the fifth sub-curve respectively start from the When the first endpoint and the second endpoint approach the 45-degree equisector, the radius of curvature gradually decreases, and when they do not reach the 45-degree equisector, they are connected by the fourth sub-curve.
- the radius of curvature at the two endpoints of the fourth sub-curve is respectively equal to the radius of curvature at the endpoint of the third sub-curve near the 45-degree equisector and the radius of curvature at the end of the fifth sub-curve near the 45-degree equisector.
- the radius of curvature of the projected shape of the light-limiting structure 2 on the preset plane changes evenly, thereby avoiding the generation of more high-order modes when light propagates in the light-limiting structure 2 , which is beneficial to reducing light leakage.
- the projection of the outer wall of the light-limiting structure 2 on the preset plane includes a closed shape formed by connecting multiple straight lines and multiple curved lines. Different situations of the closed shape formed by the connection of the multiple straight lines and the multiple curved lines will be described in detail below.
- the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane is a closed shape formed by connecting multiple straight lines and multiple curved lines.
- the waveguide structure 6 extends into the light-limiting structure 2 , and the first side where the first sidewall of the waveguide structure 6 is located coincides with one of the straight lines of the closed shape.
- the projection shape of the outer wall of the light-limiting structure 2 on the preset plane is a closed shape formed by alternately connecting multiple straight lines and multiple curved lines.
- Each section of curves in the multi-section curves includes the same sixth sub-curve and seventh sub-curve; wherein, the radius of curvature of the sixth sub-curve is from the first end point tangent to the straight line to the first end point tangent to the first sub-curve.
- the second endpoint where the seven sub-curves are connected gradually decreases.
- the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane is a closed shape formed by alternating connection of four identical straight lines and four identical curved lines.
- the waveguide structure 6 extends into the light-limiting structure 2 , and the first side where the first sidewall of the waveguide structure 6 is located coincides with one of the straight lines of the closed shape. It can be understood that when the incident light enters the light-limiting structure 2, it propagates at least along one of the straight sides, and then propagates circularly in the light-limiting structure 2 formed by the closed shape.
- the middle-excited high-order mode reduces light leakage and improves the responsivity of the photodetector.
- the size of the photodetector can be reduced, thereby reducing the parasitic parameters of the photodetector, so that the photodetector has a higher bandwidth.
- the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane is a closed shape formed by alternating connection of four identical straight lines and four identical curved lines.
- the bending angle of the curve is 90 degrees, and each section of the curve is divided into two identical sub-curves by a 45-degree bisector.
- the radius of curvature of any section of the sub-curve gradually decreases when approaching the 45-degree bisector from the sub-curve end point away from the 45-degree bisector, and the curvature radius decreases to a certain value when reaching the 45-degree bisector. value.
- the radius of curvature of the projected shape of the light-limiting structure 2 on the preset plane changes gradually, thereby avoiding the generation of more high-order modes when light propagates in the light-limiting structure 2 , which is beneficial to reducing light leakage.
- the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane is a closed shape formed by alternating connection of four identical straight lines and four identical curved lines.
- the bending angle of the curve is 90 degrees, and the curve has a 45 degree bisector.
- each section of the curve is sequentially divided into the eighth sub-curve, the ninth sub-curve and the tenth sub-curve from the first end point to the second end point, and the eighth sub-curve and the tenth sub-curve respectively start from the When the first end point and the second end point approach the 45-degree equisector, the radius of curvature gradually decreases, and when they do not reach the 45-degree equisector, they are connected by the ninth sub-curve.
- the radius of curvature at the two endpoints of the ninth sub-curve is equal to the radius of curvature at the endpoint of the eighth sub-curve near the 45-degree equisector and the radius of curvature at the endpoint of the tenth sub-curve near the 45-degree equisector.
- the radius of curvature of the projected shape of the light-limiting structure 2 on the preset plane changes evenly, thereby avoiding the generation of more high-order modes when light propagates in the light-limiting structure 2 , which is beneficial to reducing light leakage.
- the projection of the outer wall of the light-limiting structure 2 on the preset plane includes a polygon.
- Different situations in which the projection comprises polygons will be elaborated below.
- the shape of the projection of the outer wall of the light-limiting structure 2 on the preset plane is polygonal.
- the waveguide structure 6 extends into the light-limiting structure 2 , and the first side where the first sidewall of the waveguide structure 6 is located coincides with one side of the polygon.
- the angle formed by the second side where the second sidewall is located in the outer sidewall of the light limiting structure 2 and the third side where the third sidewall is located is an obtuse angle; the third sidewall is an obtuse angle for the incident light entering the The side wall where the reflection occurs for the first time behind the light-limiting structure 2.
- the polygon includes a regular polygon and the number of sides is greater than or equal to 6.
- the projected shape of the outer wall of the light-limiting structure 2 on the predetermined plane is the same as the projected shape of the absorbing structure 3 on the predetermined plane.
- the incident light propagates circularly in the light-limiting structure 2 and the germanium absorption region. Since the size of the light-limiting structure 2 and the germanium absorption region can be small and still meet the requirements of propagation, based on this, the size of the photodetector can also be small, and the photodetector The parasitic parameters will be very small, so that the silicon germanium waveguide photodetector has a relatively high bandwidth. Therefore, the silicon germanium waveguide photodetector can take into account both high bandwidth and high responsivity, which has obvious advantages.
- the projection shape of the outer wall of the light-limiting structure 2 on the preset plane may be different from the projection shape of the absorption structure 3 on the preset plane.
- the sides where the outer walls of the light-limiting structure and the absorbing structure are located adopt, for example, circular, optimally deformed quasi-circular or polygonal structures, which can confine light in the closed structure for stable transmission, while The excitation of the incident light to the high-order mode during the propagation process of the light-limiting structure and the absorbing structure is reduced, so that light leakage can be reduced, thereby improving the responsivity of the photodetector.
- the solutions provided by the embodiments of the present disclosure are applicable to silicon-germanium waveguide photodetectors, while indium gallium arsenide/indium phosphide (InGaAs/InP) materials, aluminum gallium arsenide/gallium aluminum (AlGaAs/GaAl) materials Photodetectors of semiconductor material systems such as gallium nitride (GaN) and silicon carbide (SiC) are also applicable.
- InGaAs/InP indium gallium arsenide/indium phosphide
- AlGaAs/GaAl aluminum gallium arsenide/gallium aluminum
- Photodetectors of semiconductor material systems such as gallium nitride (GaN) and silicon carbide (SiC) are also applicable.
- the incident light enters the light confinement structure tangentially to the second side where the second side wall of the light confinement structure is located through the waveguide structure, and couples the incident light to the light confinement structure through the light confinement structure.
- absorbed by the absorbing structure the sides where the outer walls of the light-limiting structure and the absorbing structure are located adopt, for example, circular, optimized deformation-like circular or polygonal structures.
- the light-limiting structure and the absorbing structure are excited to high-order modes during propagation, so that light leakage can be reduced, thereby improving the responsivity of the photodetector.
- the incident light cannot escape from the light-confining structure in the first direction due to the total reflection of the side walls in the light-confining structure, and finally all of it is coupled into the absorbing structure, and in the absorbing structure, due to the total reflection of the side walls
- the incident light will be confined in the absorbing structure, that is, the incident light propagates circularly in the light confining structure and the absorbing structure until it is completely absorbed, and the circular propagation can reduce the size requirements of the light confining structure and the absorbing structure, that is, it can reduce
- the photodetector size is required, and a smaller photodetector size can bring smaller photodetector parasitic parameters, so that the photodetector has a higher bandwidth.
- the photodetector provided by the embodiments of the present disclosure can take into account both high bandwidth and high responsivity.
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Abstract
光电探测器,包括:平板结构(1)、波导结构(6)、限光结构(2)、吸收结构(3)、第一电极结构(4)及第二电极结构(5);其中,波导结构(6)延伸至限光结构(2)中,且波导结构(6)的第一侧壁所在的第一边与限光结构(2)的外侧壁中第二侧壁所在的第二边相切;波导结构(6)用于将入射光以与第二边相切的方向导入限光结构(2)中;通过限光结构(2)侧壁的全反射将导入的光限制在限光结构(2)内进行环形传输,并通过限光结构(2)将导入的光耦合到吸收结构(3)中;第一电极结构(4)位于限光结构(2)内;第一电极结构(4)、第二电极结构(5)用于收集沿吸收结构(3)及限光结构(2)传输的电子或空穴;第一电极结构(4)与第二电极结构(5)收集的载流子的类型不同。
Description
相关申请的交叉引用
本公开基于申请号为202111530137.4、申请日为2021年12月14日、发明名称为“光电探测器”的中国专利申请提出,并要求该中国专利申请的优先权,该中国专利申请的全部内容在此引入本公开作为参考。
本公开涉及半导体技术领域,具体地,涉及一种光电探测器。
借鉴于大规模集成电路的发展路线,国内外正在开展研究将有源器件(例如调制器、光电探测器等)和光波导器件(例如分光器/耦合器等)集成到一个衬底上,以实现具有类似大规模集成电路的优点的光子芯片。光子芯片具有低成本、小尺寸、低功耗、灵活扩展和高可靠性等特点。目前硅基光子芯片被业界认为是最有前景的光子芯片。硅基光子芯片可以将微电子和光电子结合起来,充分发挥硅基微电子先进成熟的工艺技术、高度集成化、低成本等优势,具有广泛的市场前景。
硅基光子芯片通常采用绝缘体上硅(Si1icon On Insulator,SOI)材料形成光波导,光波导由Si芯层和SiO
2包层形成,芯层和包层间较大的折射率差异对光场有很强的限制作用,可实现小到微米量级的波导弯曲半径,从而为硅基光子芯片小型化和高密度集成化提供了实现的基础。
在光通信领域,硅基光子芯片的接收端常使用的器件为光电探测器,如锗硅波导型光电探测器。锗硅波导型光电探测器是一种将高速光信号转化为电流信号的器件,是硅基光子芯片的关键器件。锗硅波导型光电探测器主要依靠锗材料对光的吸收产生光电流。相关技术中,需要兼顾 光电探测器带宽的同时进一步提高光电探测器的响应度。
发明内容
有鉴于此,本公开实施例期望提供一种光电探测器。
为达到上述目的,本公开的技术方案是这样实现的:
所述光电探测器包括:平板结构、波导结构、限光结构、吸收结构、第一电极结构及第二电极结构;其中,
所述波导结构延伸至所述限光结构中,且所述波导结构的第一侧壁所在的第一边与所述限光结构的外侧壁中的第二侧壁所在的第二边相切;所述波导结构用于将入射光以与所述第二边相切的方向导入所述限光结构中;
通过所述限光结构侧壁的全反射将导入的光限制在限光结构内进行环形传输,并通过限光结构将导入的光耦合到吸收结构中;
所述吸收结构至少部分位于所述限光结构上;通过所述吸收结构侧壁的全反射将耦合的光限制在吸收结构内进行环形传输,并将耦合的光转化为电子和空穴;
所述平板结构包围所述波导结构和限光结构;
所述第一电极结构位于所述限光结构内;所述第二电极结构位于所述限光结构外侧且与所述限光结构接触;所述第一电极结构、第二电极结构用于收集沿所述吸收结构及所述限光结构传输的电子或空穴;所述第一电极结构与第二电极结构收集的载流子的类型不同。
上述方案中,所述限光结构包括第一掺杂区及包围所述第一掺杂区的第二掺杂区;其中,所述第一掺杂区与所述第二掺杂区掺杂类型相反;
所述第一电极结构位于所述第一掺杂区内侧且与所述第一掺杂区接触,所述第一电极结构用于收集沿所述吸收结构及所述第一掺杂区传输的电子或空穴;
所述第二电极结构用于收集沿所述吸收结构及所述第二掺杂区传输的电子或空穴。
上述方案中,所述光电探测器还包括位于所述第一掺杂区与所述第二掺杂区之间的本征区,其中,
所述本征区的材料与所述限光结构的材料相同;
或者,
所述本征区的材料与所述吸收结构的材料相同。
上述方案中,所述光电探测器还包括位于所述第一掺杂区与所述第二掺杂区之间沿所述限光结构厚度的方向依次层叠设置的第一本征区、第二本征区,其中,
所述第一本征区的材料与所述限光结构的材料相同;所述第二本征区的材料与所述吸收结构的材料相同。
上述方案中,所述第一掺杂区、所述本征区及所述第二掺杂区在预设平面的投影之和覆盖所述吸收结构在所述预设平面的投影;所述吸收结构在所述预设平面的投影覆盖所述本征区在所述预设平面的投影;
其中,所述预设平面垂直于所述限光结构厚度的方向。
上述方案中,所述第一电极结构包括第一电极、第一电极接触区以及第三掺杂区;其中,所述第三掺杂区位于所述第一掺杂区内侧且与所述第一掺杂区接触;所述第一电极接触区位于所述第三掺杂区表面及向下一定深度的区域,所述第一电极位于所述第一电极接触区之上;所述第一电极用于收集依次沿所述吸收结构、第一掺杂区、所述第三掺杂区以及所述第一电极接触区传输的电子或空穴;
所述第二电极结构包括第二电极、第二电极接触区以及第四掺杂区;其中,所述第四掺杂区包围所述限光结构,所述第二电极接触区位于所述第四掺杂区表面及向下一定深度的区域,所述第二电极位于所述第二电极接触区之上;所述第二电极用于收集依次沿所述吸收结构、所述第二掺杂 区及所述第四掺杂区传输的电子或空穴。
上述方案中,所述第二掺杂区的掺杂浓度小于等于所述第四掺杂区的掺杂浓度,所述第四掺杂区的掺杂浓度小于所述第二电极接触区的掺杂浓度;所述第一掺杂区的掺杂浓度小于等于所述第三掺杂区的掺杂浓度,所述第三掺杂区的浓度小于所述第一电极接触区的掺杂浓度。
上述方案中,所述第一电极接触区远离所述吸收结构,且所述第三掺杂区的厚度小于等于所述限光结构的厚度;所述波导结构的厚度与所述限光结构的厚度相同。
上述方案中,所述波导结构在预设平面的投影的形状包括长条状;
所述限光结构的外侧壁在所述预设平面的投影的形状包括由至少一段直线和/或至少一段曲线形成的封闭图形,且所述限光结构的外侧壁中的第二侧壁所在的第二边和外侧壁中第三侧壁所在的第三边形成的角度为钝角;
其中,所述第三侧壁为所述入射光进入所述限光结构后第一次发生反射处的侧壁。
上述方案中,所述限光结构的外侧壁在所述预设平面的投影的形状包括以下之一:
圆形;
多段曲线连接形成的封闭形状;
多段直线和多段曲线连接形成的封闭形状;
多边形。
本公开实施例提供的光电探测器,通过波导结构将入射光沿与所述限光结构的第二侧壁所在的第二边相切地进入限光结构并通过限光结构将入射光耦合到吸收结构而被吸收。同时,限光结构和吸收结构的外侧壁所在的边采用例如圆形、优化变形的类圆形或多边形结构,这种结构能够将光限制在封闭结构内稳定传输,同时减少所述入射光在限光结构和吸收结构 传播过程中向高阶模激发,如此,能够减少光的泄露,从而提高光电探测器的响应度。同时,所述入射光在限光结构中由于侧壁的全反射作用在第一方向无法逃离限光结构,最后全部耦合到吸收结构中,而在吸收结构中也将由于侧壁的全反射作用入射光将被限制在吸收结构中,也就是说,入射光在限光结构和吸收结构中呈环形传播直至被完全吸收,环形传播可以减少限光结构和吸收结构的尺寸需求,即可以减小光电探测器尺寸需求,而较小的光电探测器尺寸可以带来较小的光电探测器的寄生参数,从而使得所述光电探测器具有较高带宽。此外,本公开实施例中通过将第一电极结构设置在限光结构内,可以避免吸收结构与第一电极结构的接触,从而减少由于吸收结构与第一电极结构接触而产生的光损失,进一步提高光电探测器的响应度。因此,本公开实施例提供的光电探测器可以兼顾高带宽和高响应度。
图1为本公开实施例提供的一种光电探测器的俯视示意;
图2为本公开实施例提供的另一种光电探测器的俯视示意;
图3a及图3b为图1、图2中沿A1-A1方向的截面图;
图4为图1、图2中沿B1-B1方向的截面图。
以下结合说明书附图及具体实施例对本公开的技术方案做进一步的详细阐述。
在本公开的描述中,需要理解的是,术语“长度”、“宽度”、“深度”、“上”、“下”、“外”等指示的方位或位置关系为基于附图所示的方位或位置关系,仅是为了便于描述本公开和简化描述,而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作,因此不能理 解为对本公开的限制。
在本公开实施例中,术语“衬底”是指在其上添加后续材料层的材料。衬底本身可以被图案化。被添加在衬底顶部的材料可以被图案化或者可以保持未被图案化。此外,衬底可以包括多种半导体材料,例如硅、锗、砷化嫁、磷化铟等。替代地,衬底可以由非导电材料制成,例如玻璃、塑料或蓝宝石晶圆。
在本公开实施例中,术语“层”是指包括具有厚度的区域的材料部分。层可以在下方或上方结构的整体之上延伸,或者可以具有小于下方或上方结构范围的范围。此外,层可以是厚度小于连续结构厚度的均质或非均质连续结构的区域。例如,层可位于连续结构的顶表面和底表面之间,或者层可在连续结构顶表面和底表面处的任何水平面对之间。层可以水平、垂直和/或沿倾斜表面延伸。层可以包括多个子层。例如,互连层可包括一个或多个导体和接触子层(其中形成互连线和/或过孔触点)、以及一个或多个电介质子层。
在本公开实施例中,术语“第一”、“第二”等是用于区别类似的对象,而不必用于描述特定的顺序或先后次序。
需要说明的是,本公开实施例所记载的技术方案之间,在不冲突的情况下,可以任意组合。
锗硅波导型光电探测器一般采用方形结构,光从限光结构一端入射,从对应的另一端出射,经历单程吸收。一方面,为提高光电探测器的响应度,需要尽可能多的吸收光,从而需要增加光电探测器的尺寸,以获得较大的响应度;另一方面,当光电探测器尺寸增加时,会增加光电探测器的寄生参数,从而使光电探测器的光电带宽下降。也就是说,目前光电探测器的响应度和光电带宽之间存在相互制约的关系。此外,在实际应用中,锗硅波导型光电探测器需要金属电极与锗接触并掺杂锗形成P-I-N结。然而,金属接触会影响锗的光吸收,使得锗吸收区产生光损失,从而导致锗 硅波导型光电探测器响应度下降。
基于此,本公开实施例中旨在提供一种兼顾高响应度和高带宽的光电探测器。在本公开的各实施例中,通过波导结构将入射光沿与所述限光结构的第二侧壁所在的第二边相切地进入限光结构并通过限光结构将入射光耦合到吸收结构而被吸收。同时,限光结构和吸收结构的外侧壁所在的边采用例如圆形、优化变形的类圆形或多边形结构,这种结构能够将光限制在封闭结构内稳定传输,同时减少所述入射光在限光结构和吸收结构传播过程中向高阶模激发,如此,能够减少光的泄露,从而提高光电探测器的响应度。同时,所述入射光在限光结构中由于侧壁的全反射作用在第一方向无法逃离限光结构,最后全部耦合到吸收结构中,而在吸收结构中也将由于侧壁的全反射作用入射光将被限制在吸收结构中,也就是说,入射光在限光结构和吸收结构中呈环形传播直至被完全吸收,环形传播可以减少限光结构和吸收结构的尺寸需求,即可以减小光电探测器尺寸需求,而较小的光电探测器尺寸可以带来较小的光电探测器的寄生参数,从而使得所述光电探测器具有较高带宽。此外,本公开实施例中通过将第一电极结构设置在限光结构内侧且与所述限光结构接触,可以避免吸收结构与第一电极结构的接触,从而减少由于吸收结构与第一电极结构接触而产生的光损失,进一步提高光电探测器的响应度。因此,本公开实施例提供的光电探测器可以兼顾高带宽和高响应度。
本公开实施例提供了一种光电探测器,包括:平板结构、波导结构、限光结构、吸收结构、第一电极结构及第二电极结构;其中,
所述波导结构延伸至所述限光结构中,且所述波导结构的第一侧壁所在的第一边与所述限光结构的外侧壁中的第二侧壁所在的第二边相切;所述波导结构用于将入射光以与所述第二边相切的方向导入所述限光结构中;
通过所述限光结构侧壁的全反射将导入的光限制在限光结构内进行环 形传输,并通过限光结构将导入的光耦合到吸收结构中;
所述吸收结构至少部分位于所述限光结构上;通过所述吸收结构侧壁的全反射将耦合的光限制在吸收结构内进行环形传输,并将耦合的光转化为电子和空穴;
所述平板结构包围所述波导结构和限光结构;
所述第一电极结构位于所述限光结构内;所述第二电极结构位于所述限光结构外侧且与所述限光结构接触;所述第一电极结构、第二电极结构用于收集沿所述吸收结构及所述限光结构传输的电子或空穴;所述第一电极结构与第二电极结构收集的载流子的类型不同。
图1为本公开实施例提供的一种光电探测器的俯视示意,图2为本公开实施例提供的另一种光电探测器的俯视示意。需要说明的是,图1和图2中展示的光电探测器的结构类似,不同主要体现在二者在限光结构2及吸收结构3在预设平面上投影的形状。下文将根据图1对所述光电探测器进行示例性描述。
如图1所示,所述光电探测器包括平板结构1、波导结构6、限光结构2、吸收结构3、第一电极结构4及第二电极结构5;其中,所述波导结构6延伸至所述限光结构2中,且所述波导结构6的第一侧壁所在的第一边与所述限光结构2的外侧壁中的第二侧壁所在的第二边相切;所述波导结构6用于将入射光以与所述第二边相切的方向导入所述限光结构2中;通过所述限光结构2侧壁的全反射将导入的光限制在限光结构内2进行环形传输,并通过限光结构2将导入的光耦合到吸收结构中;所述吸收结构3位于所述限光结构2上;通过所述吸收结构3侧壁的全反射将耦合的光限制在吸收结构3内进行环形传输,并将耦合的光转化为电子和空穴;所述平板结构1包围所述波导结构6和限光结构2;所述第一电极结构4位于所述限光结构2内;所述第二电极结构5位于与所述限光结构2外侧且与所述限光结构2接触;所述第一电极结构4、第二电极结构5用于收集沿所述吸收结 构3及所述限光结构2传输的电子或空穴;所述第一电极结构4与第二电极结构5收集的载流子的类型不同。
实际应用中,所述波导结构6用于传播入射光,所述入射光通过波导结构6进入限光结构。所述波导结构6可以为硅波导,所述硅波导包括硅(Si)芯层和二氧化硅(SiO
2)包层。这里,所述波导结构6延伸至所述限光结构2中,且所述波导结构6的第一侧壁所在的第一边与所述限光结构2的第二侧壁所在的第二边相切;所述波导结构6用于将入射光以与所述第二边相切的方向导入所述限光结构2中。可以理解的是,通过所述波导结构6可以将入射光以与所述限光结构2的外侧壁相切的方向导入所述限光结构2中,降低所述入射光在波导结构6和限光结构2中传播过程中的突变影响,从而减少光在传播过程中激发的高阶模,提高入射光在传播过程中的稳定性,减少光的泄露,进而提高光电探测器的响应度。
实际应用中,如图4所示,所述平板结构1的厚度小于所述波导结构6的厚度;所述平板结构1和波导结构6构成脊形入射波导,所述入射波导为硅波导,用于传播入射光,所述入射光通过入射波导进入限光结构2并耦合进入吸收结构3。需要说明的是,在本公开各实施例中,不对入射波导的具体结构进行限制。具体来说,本公开实施例中的光电探测器可以包括脊形入射波导以及其它形状的波导。这里仅以具有脊形入射波导的锗硅波导型光电探测器对本公开实施例提供的方案进行示例性描述。
实际应用中,所述限光结构2用于接收所述入射波导传播的入射光并通过侧壁的全反射将导入的光在第一方向上限制在耦合结构内进行环形传输,同时将导入的光通过限光结构耦合到吸收结构3中。这里,所述限光结构2的材料可以包括轻掺杂硅。
可以理解的是,所述入射光通过所述限光结构2侧壁的全反射作用在第一方向上限制在耦合结构内进行环形传输,同时全部通过限光结构2耦合到吸收结构3中,然后被所述吸收结构3全部吸收。在本公开实施例中, 所述限光结构2将导入的光全部耦合到吸收结构3中可以理解为,从理论设计上进入限光结构2的光可以100%地耦合进入吸收结构3中,但实际应用中,由于工艺等因素,如反射面不可避免的存在极少量的散射、掺杂区的吸收,从而不能完全到达100%地进入到吸收结构3中,以上造成的光损失未包括在上述的“全部”的含义中。
需要说明的是,当所述限光结构2与所述吸收结构3堆叠设置时,所述第一方向垂直于所述堆叠方向。可以理解的是,当所述限光结构2与所述吸收结构3竖直堆叠设置时,所述第一方向为水平方向。
实际应用中,所述吸收结构3位于所述限光结构2上,用于通过侧壁的全反射将耦合的光在第一方向上限制在吸收结构3内进行环形传输并将耦合的光转化为电子和空穴。这里,所述吸收结构3可以包括锗吸收区。
实际应用中,所述平板结构1包围所述波导结构6和限光结构2;所述平板结构1的厚度小于所述限光结构2的厚度。可以理解的是,所述平板结构1和所述限光结构2构成脊波导结构。
实际应用中,所述第一电极结构4位于所述限光结构2内侧且与所述限光结构2接触;所述第二电极结构5位于所述平板结构1中且所述第二电极结构5包围所述限光结构2;所述第一电极结构4、第二电极结构5用于收集沿所述吸收结构3及所述限光结构2传输的电子或空穴;所述第一电极结构4与第二电极结构5收集的载流子的类型不同。举例来说,光子产生的电子空穴对在外加电场的作用下向两极移动,当所述第一电极结构4收集的载流子为电子时,所述第二电极结构5收集的载流子为空穴;或者当所述第一电极结构4收集的载流子为空穴时,所述第二电极结构5收集的载流子为电子。
这里,所述第一电极结构4与第二电极结构5包括金属电极。所述第一电极结构4位于所述限光结构2内侧且与所述限光结构2接触,从而避免了锗吸收区与金属电极的接触,减少了金属电极的光学吸收,进一步提 高了响应度。此外,不需要锗与金属进行欧姆接触,工艺简单、成本较低。
图3a和图3b为图1、图2中沿A1-A1方向的截面图。在一实施例中,如图3a和图3b所示,所述限光结构2包括第一掺杂区2-1及包围所述第一掺杂区2-1的第二掺杂区2-3;其中,所述第一掺杂区2-1与所述第二掺杂区2-3掺杂类型相反;所述第一电极结构4位于所述第一掺杂区2-1内侧且与所述第一掺杂区2-1接触,所述第一电极结构4用于收集沿所述吸收结构3及所述第一掺杂区2-1传输的电子或空穴;所述第二电极结构5用于收集沿所述吸收结构3及所述第二掺杂区2-3传输的电子或空穴。
实际应用中,如图1所示,所述第一掺杂区2-1与所述第二掺杂区2-3均包括环形波导结构。所述第一掺杂区2-1环形波导结构和所述第二掺杂区2-3环形波导结构掺杂类型相反。
这里,所述第一掺杂区2-1环形波导结构和所述第二掺杂区2-3环形波导结构在预设平面的投影均包括圆环形。实际应用中,所述第一掺杂区2-1环形波导结构和所述第二掺杂区2-3环形波导结构在预设平面的投影包括如图2所示的变形圆环形或正多边环形等封闭图形。需要说明的是,由于所述第一掺杂区2-1环形波导结构包围部分第一电极结构4,所述第一掺杂区2-1环形波导结构的内侧边与部分第一电极结构4的外侧边重合,因此,所述第一掺杂区2-1环形波导结构在所述预设平面的投影根据第一电极结构4的形状而变化。
在一实施例中,如图3a所示,所述光电探测器还包括位于所述第一掺杂区2-1与所述第二掺杂区2-3之间的本征区2-2,其中,所述本征区2-2的材料与所述限光结构2的材料相同;或者,所述本征区2-2的材料与所述吸收结构3的材料相同。
实际应用中,所述本征区2-2包括环形波导结构。当所述本征区2-2的材料与所述限光结构2的材料相同时,所述限光结构2包括所述第一掺杂区2-1环形波导结构、本征区2-2环形波导结构和第二掺杂区2-3环形波导 结构;当所述本征区2-2的材料与所述吸收结构3的材料相同时,所述吸收结构3还包括本征区2-2环形波导结构。这里,所述第二掺杂区2-3环形波导结构的内侧边和本征区2-2环形波导结构的外侧边重合,本征区2-2环形波导结构的内侧边和所述第一掺杂区2-1环形波导结构的外侧边重合。可以理解的是,所述第一掺杂区2-1与所述第二掺杂区2-3之间的本征区2-2增加了吸收结构3中的电场强度从而增加了载流子的流动速度,从而增加探测器带宽;此外,在光电探测器的设计过程中,通过调整本征区2-2的宽度可以为光电探测器的尺寸设计提供更大的自由度。
在一实施例中,如图3b所示,所述光电探测器还包括位于所述第一掺杂区2-1与所述第二掺杂区2-3之间沿所述限光结构2厚度的方向依次层叠设置的第一本征区2-2A、第二本征区2-2B,其中,所述第一本征区2-2A的材料与所述限光结构2的材料相同;所述第二本征区2-2B的材料与所述吸收结构3的材料相同。也就是说,所述限光结构2还包括所述第一本征区2-2A;所述吸收结构3还包括所述第二本征区2-2B。
在一实施例中,所述第一掺杂区2-1、所述本征区2-2及所述第二掺杂区2-3在预设平面的投影之和覆盖所述吸收结构3在所述预设平面的投影;所述吸收结构3在所述预设平面的投影覆盖所述本征区2-2在所述预设平面的投影;其中,所述预设平面垂直于所述限光结构2厚度的方向。可以理解的是,所述第一掺杂区2-1、所述本征区2-2及所述第二掺杂区2-3在预设平面的投影之和的面积大于所述吸收结构3在预设平面的投影的面积,可以更好地为所述吸收结构3提供生长平台;所述吸收结构3在所述预设平面的投影覆盖所述本征区2-2在所述预设平面的投影。需要说明的是,所述第一掺杂区2-1、所述本征区2-2及所述第二掺杂区2-3在预设平面的投影之和分别包括所述第一掺杂区2-1在预设平面的投影、所述本征区2-2在预设平面的投影以及所述第二掺杂区2-3在预设平面的投影叠加之后得到的投影。
在一实施例中,如图1及图3a和图3b所示,所述第一电极结构4包括第一电极4-1、第一电极接触区4-2以及第三掺杂区4-3;其中,所述第三掺杂区4-3位于所述第一掺杂区2-1环形波导结构内侧,所述第一掺杂区2-1环形波导结构的内侧边与所述第三掺杂区4-3的外侧边重合,所述第一电极接触区4-2位于所述第三掺杂区4-3表面及向下一定深度的区域,所述第一电极4-1位于所述第一电极接触区4-2之上;所述第一电极4-1用于收集依次沿所述吸收结构3、第一掺杂区2-1、所述第三掺杂区4-3以及所述第一电极接触区4-2传输的电子或空穴;所述第二电极结构5包括第二电极5-1、第二电极接触区5-2以及第四掺杂区5-3;其中,所述第四掺杂区5-3包围所述限光结构2,所述第二电极接触区5-2位于所述第四掺杂区5-3表面及向下一定深度的区域,所述第二电极5-1位于所述第二电极接触区5-2之上;所述第二电极5-1用于收集依次沿所述吸收结构3、所述第二掺杂区2-3及所述第四掺杂区5-3传输的电子或空穴。这里,所述第二电极5-1在所述预设平面的投影为环形且远离所述限光结构2。需要说明的是,所述第一电极4-1及所述第二电极5-1的具体形状根据电极接触区的形状而变化,并不限于本公开具体实施例。
实际应用中,所述第一电极接触区4-2的掺杂浓度可以高于第三掺杂区4-3的掺杂浓度,第二电极接触区5-2的掺杂浓度可以高于第四掺杂区5-3的掺杂浓度,以减小第一电极接触区4-2和第二电极接触区5-2的电阻,使电极与电极接触区形成良好的欧姆接触,进一步提高光电探测器的带宽。
在一实施例中,所述第二掺杂区2-3的掺杂浓度小于等于所述第四掺杂区5-3的掺杂浓度;所述第一掺杂区2-1的掺杂浓度小于等于所述第三掺杂区4-3的掺杂浓度。
需要说明的是,为了降低光在限光结构2内的吸收损耗,位于限光结构2中的第二掺杂区2-3的掺杂浓度小于等于所述第四掺杂区5-3的掺杂浓度;同时,位于限光结构2中的第一掺杂区2-1的掺杂浓度小于等于所述第 三掺杂区4-3的掺杂浓度。
在一实施例中,所述第三掺杂区的厚度小于等于所述限光结构2的厚度,如此,可以进一步降低光向高阶模激发,降低光的泄露,从而进一步提高光电探测器的响应度。
在一实施例中,所述波导结构6的厚度与所述限光结构2的厚度相同。实际应用中,所述波导结构6的厚度与所述限光结构2的厚度相同,所述波导结构6的厚度大于所述平板结构1的厚度。如此,可以减少光从波导结构6进入限光结构2入口处光的反射及折射,从而减少光的泄露。
在一实施例中,所述波导结构6在预设平面的投影的形状包括长条状;所述限光结构2的外侧壁在所述预设平面的投影的形状包括由至少一段直线和/或至少一段曲线形成的封闭图形,且所述限光结构2的外侧壁中的第二侧壁所在的第二边和外侧壁中第三侧壁所在的第三边形成的角度为钝角;其中,所述第三侧壁为所述入射光进入所述限光结构2后第一次发生反射处的侧壁。
实际应用中,所述限光结构2的外侧壁的在所述预设平面上的投影包括直线时,所述波导结构6的第一侧壁所在的第一边与所述直线相切;所述限光结构2的一个侧壁在所述预设平面上的投影只为曲线时,所述波导结构6的第一侧壁所在的第一边与所述曲线相切。
这里,所述限光结构2的外侧壁所在的边包括多段直线时,所述限光结构的外侧壁中的第二侧壁所在的第二边和第三侧壁所在的第三边形成的角度为钝角;所述限光结构2外侧壁所在的边包括至少一条曲线时,所述限光结构2的外侧壁中的第二侧壁所在的第二边和第三侧壁所在的第三边均可以看作是曲线所在的边。需要说明的是,曲线可以看作是无数段直线组成的图形。可以理解的是,入射光进入所述限光结构后第一次发生反射处的反射角不等于0度。也就是说,入射光进入所述限光结构后并不会从所述入射光入口处直接反射回去,从而避免了光从入射光入口处泄露。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状包括以下之一:
圆形;
多段曲线连接形成的封闭形状;
多段直线和多段曲线连接形成的封闭形状;
多边形。
需要说明的是,在一些实施例中,所述限光结构2还包括内侧壁。所述限光结构2的内侧壁在所述预设平面的投影的形状可以与所述限光结构2的外侧壁在所述预设平面的投影的形状相同,也可以不同。具体地,当所述限光结构2的外侧壁在所述预设平面的投影的形状包括圆形时,所述限光结构2的内侧壁在所述预设平面的投影的形状可以为圆形,也可以为多边形或其它形状;当所述限光结构2的内侧壁在所述预设平面的投影的形状可以为圆形时,所述限光结构2在所述预设平面的投影为圆环形。实际应用中,所述限光结构2在所述预设平面的投影可以包括一个圆环形或多个同心圆环形。
实际应用中,所述限光结构2的外侧壁和内侧壁在所述预设平面的投影包括多种不同的形状,下面各实施例中将以限光结构2的外侧壁在所述预设平面的投影的形状为例阐述所述限光结构2在所述预设平面的投影的不同形状。需要说明的是,以下各实施例中,所述限光结构2的内侧壁在所述预设平面的投影的形状与外侧壁相同,在此不再赘述。
在一实施例中,如图1所示,所述限光结构2的外侧壁在所述预设平面的投影的形状为圆形。所述波导结构6延伸至所述限光结构2中,且所述波导结构6的第一侧壁所在的第一边与所述限光结构2的圆边相切。可以理解的是,当所述限光结构2的外侧壁和内侧壁在所述预设平面的投影的形状均为圆形时,所述限光结构2在所述预设平面的投影的形状为圆环形。如此,入射光在所述圆环形限光结构2中环形传播,因而可以减小光 电探测器尺寸,从而减小光电探测器的寄生参数,使得所述光电探测器具有较高带宽。这里,所述预设平面垂直于所述限光结构厚度的方向,所述平板结构1所在的平面与预设平面平行。
实际应用中,所述限光结构2的外侧壁在所述预设平面的投影包括多段曲线连接形成的封闭形状。下文将详细阐述所述多段曲线连接形成的封闭形状的不同情形。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状为多段曲线连接形成的封闭形状。所述波导结构6延伸至所述限光结构2中,且所述波导结构6的第一侧壁所在的第一边与所述多段曲线中的其中一条曲线相切,所述其中一条曲线在切点处的曲率半径趋近于无穷大。其中,所述多段曲线中的每一段曲线均包括相同的第一子曲线和第二子曲线;所述第一子曲线的曲率半径在第一端点处趋近于无穷大且所述第一子曲线的曲率半径从第一端点处至与所述第二子曲线相连的第二端点处逐渐减小。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状为四段相同曲线连接形成的封闭形状。所述曲线弯曲角度为90度,每一段所述曲线被45度等分线分为相同的两段子曲线。其中,任一段子曲线从远离所述45度等分线的子曲线端点向所述45度等分线靠近时曲率半径逐渐减小,到达所述45度等分线时曲率半径减小到一定值。所述限光结构2在所述预设平面的投影的形状的曲率半径逐渐变化,从而避免了光在限光结构2中传播时产生较多的高阶模,有利于减少光泄露。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状为四段相同曲线连接形成的封闭形状。所述曲线弯曲角度为90度,所述曲线具有45度等分线。其中,每一段所述曲线从第一端点至第二端点顺次分为第三子曲线、第四子曲线及第五子曲线,所述第三子曲线、第五子曲线分别从所述第一端点、第二端点向所述45度等分线靠近时曲率半径逐渐 减小,未到达所述45度等分线时由所述第四子曲线连接。所述第四子曲线两个端点处的曲率半径分别与第三子曲线靠近45度等分线的端点处的曲率半径、第五子曲线靠近45度等分线的端点处的曲率半径相等。所述限光结构2在所述预设平面的投影的形状的曲率半径均匀变化,从而避免了光在限光结构2中传播时产生较多的高阶模,有利于减少光泄露。
实际应用中,所述限光结构2的外侧壁在所述预设平面的投影包括多段直线和多段曲线连接形成的封闭形状。下文将详细阐述所述多段直线和多段曲线连接形成的封闭形状的不同情形。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状为多段直线和多段曲线连接形成的封闭形状。所述波导结构6延伸至所述限光结构2中,且所述波导结构6的第一侧壁所在的第一边与所述封闭形状的其中一条直线重合。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状为多段直线和多段曲线交替连接形成的封闭形状。所述多段曲线中的每一段曲线均包括相同的第六子曲线和第七子曲线;其中,所述第六子曲线的曲率半径从与直线相切的第一端点处至与所述第七子曲线相连的第二端点处逐渐减小。
在一实施例中,如图2所示,所述限光结构2的外侧壁在所述预设平面的投影的形状为四段相同直线和四段相同曲线交替连接形成的封闭形状。所述波导结构6延伸至所述限光结构2中,且所述波导结构6的第一侧壁所在的第一边与所述封闭形状的其中一条直线重合。可以理解的是,入射光进入所述限光结构2时至少沿其中一条直边直线传播,随后在所述封闭形状构成的限光结构2中环形传播,因此,一方面可以减少光在传播过程中激发的高阶模,减少光的泄露,提高光电探测器的响应度,另一方面可以减小光电探测器尺寸,从而减小光电探测器的寄生参数,使得所述光电探测器具有较高带宽。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状为四段相同直线和四段相同曲线交替连接形成的封闭形状。所述曲线弯曲角度为90度,每一段所述曲线被45度等分线分为相同的两段子曲线。其中,任一段子曲线从远离所述45度等分线的子曲线端点向所述45度等分线靠近时曲率半径逐渐减小,到达所述45度等分线时曲率半径减小到一定值。所述限光结构2在所述预设平面的投影的形状的曲率半径逐渐变化,从而避免了光在限光结构2中传播时产生较多的高阶模,有利于减少光泄露。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状为四段相同直线和四段相同曲线交替连接形成的封闭形状。所述曲线弯曲角度为90度,所述曲线具有45度等分线。其中,每一段所述曲线从第一端点至第二端点顺次分为第八子曲线、第九子曲线及第十子曲线,所述第八子曲线、第十子曲线分别从所述第一端点、第二端点向所述45度等分线靠近时曲率半径逐渐减小,未到达所述45度等分线时由所述第九子曲线连接。所述第九子曲线两个端点处的曲率半径分别与第八子曲线靠近45度等分线的端点处的曲率半径、第十子曲线靠近45度等分线的端点处的曲率半径相等。所述限光结构2在所述预设平面的投影的形状的曲率半径均匀变化,从而避免了光在限光结构2中传播时产生较多的高阶模,有利于减少光泄露。
实际应用中,所述限光结构2的外侧壁在所述预设平面的投影包括多边形。下文将详细阐述所述投影包括多边形的不同情形。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状为多边形。所述波导结构6延伸至所述限光结构2中,且所述波导结构6的第一侧壁所在的第一边与所述多边形的其中一边重合。所述限光结构2的外侧壁中的第二侧壁所在的第二边和第三侧壁所在的第三边形成的角度为钝角;所述第三侧壁为所述入射光进入所述限光结构2后第一次发生反 射处的侧壁。可以理解的是,入射光进入所述限光结构2后第一次发生反射处的反射角不等于0度。也就是说,入射光进入所述限光结构2后并不会从所述入射光入口处反射回去,从而避免了光从入射光入口处泄露。
在一实施例中,所述多边形包括正多边形且边数大于等于6。
在一实施例中,所述限光结构2的外侧壁在所述预设平面的投影的形状为正八边形。所述波导结构6延伸至所述限光结构2中,且所述波导结构6的第一侧壁所在的第一边与所述正八边形的其中一边相切。入射光从所述波导结构6进入所述限光结构2后沿所述正八边形环形传播。
上文阐述了所述限光结构2的外侧壁在所述预设平面的投影的形状的不同情形,实际应用中,所述吸收结构3在所述预设平面投影的形状也包括多种情形。
在一实施例中,如图1至图2所示,所述限光结构2的外侧壁在所述预设平面投影的形状与所述吸收结构3在所述预设平面投影的形状相同。入射光在限光结构2和锗吸收区环形传播,由于限光结构2和锗吸收区的尺寸可以很小且依然满足传播的需求,基于此,光电探测器尺寸也可以很小,光电探测器寄生参数就会很小,从而使得所述锗硅波导型光电探测器具有较高带宽,因此,使得所述锗硅波导型光电探测器可以同时兼顾高带宽和高响应度,具有明显优势。
实际应用中,所述限光结构2的外侧壁在所述预设平面投影的形状与所述吸收结构3在所述预设平面投影的形状可以不同。
在上述多个实施例中,限光结构和吸收结构的外侧壁所在的边采用例如圆形、优化变形的类圆形或多边形结构,这种结构能够将光限制在封闭结构内稳定传输,同时减少所述入射光在限光结构和吸收结构传播过程中向高阶模激发,如此,能够减少光的泄露,从而提高光电探测器的响应度。
需要说明的是,本公开实施例提供的方案适用于锗硅波导型光电探测器,同时铟镓砷/铟磷(InGaAs/InP)系材料、铝镓砷/镓铝(AlGaAs/GaAl) 系材料、氮化镓(GaN)系材料、碳化硅(SiC)等半导体材料体系的光电探测器亦可适用。
以上所述,仅为本公开的具体实施方式,但本公开的保护范围并不局限于此,任何熟悉本技术领域的技术人员在本公开揭露的技术范围内,可轻易想到变化或替换,都应涵盖在本公开的保护范围之内。因此,本公开的保护范围应以所述权利要求的保护范围为准。
本公开实施例提供的光电探测器,通过波导结构将入射光沿与所述限光结构的第二侧壁所在的第二边相切地进入限光结构并通过限光结构将入射光耦合到吸收结构而被吸收。同时,限光结构和吸收结构的外侧壁所在的边采用例如圆形、优化变形的类圆形或多边形结构,这种结构能够将光限制在封闭结构内稳定传输,同时减少所述入射光在限光结构和吸收结构传播过程中向高阶模激发,如此,能够减少光的泄露,从而提高光电探测器的响应度。同时,所述入射光在限光结构中由于侧壁的全反射作用在第一方向无法逃离限光结构,最后全部耦合到吸收结构中,而在吸收结构中也将由于侧壁的全反射作用入射光将被限制在吸收结构中,也就是说,入射光在限光结构和吸收结构中呈环形传播直至被完全吸收,环形传播可以减少限光结构和吸收结构的尺寸需求,即可以减小光电探测器尺寸需求,而较小的光电探测器尺寸可以带来较小的光电探测器的寄生参数,从而使得所述光电探测器具有较高带宽。此外,本公开实施例中通过将第一电极结构设置在限光结构内,可以避免吸收结构与第一电极结构的接触,从而减少由于吸收结构与第一电极结构接触而产生的光损失,进一步提高光电探测器的响应度。因此,本公开实施例提供的光电探测器可以兼顾高带宽和高响应度。
Claims (10)
- 一种光电探测器,包括:平板结构、波导结构、限光结构、吸收结构、第一电极结构及第二电极结构;其中,所述波导结构延伸至所述限光结构中,且所述波导结构的第一侧壁所在的第一边与所述限光结构的外侧壁中的第二侧壁所在的第二边相切;所述波导结构用于将入射光以与所述第二边相切的方向导入所述限光结构中;通过所述限光结构侧壁的全反射将导入的光限制在限光结构内进行环形传输,并通过限光结构将导入的光耦合到吸收结构中;所述吸收结构至少部分位于所述限光结构上;通过所述吸收结构侧壁的全反射将耦合的光限制在吸收结构内进行环形传输,并将耦合的光转化为电子和空穴;所述平板结构包围所述波导结构和限光结构;所述第一电极结构位于所述限光结构内;所述第二电极结构位于所述限光结构外侧且与所述限光结构接触;所述第一电极结构、第二电极结构用于收集沿所述吸收结构及所述限光结构传输的电子或空穴;所述第一电极结构与第二电极结构收集的载流子的类型不同。
- 根据权利要求1所述的光电探测器,其中,所述限光结构包括第一掺杂区及包围所述第一掺杂区的第二掺杂区;其中,所述第一掺杂区与所述第二掺杂区掺杂类型相反;所述第一电极结构位于所述第一掺杂区内侧且与所述第一掺杂区接触,所述第一电极结构用于收集沿所述吸收结构及所述第一掺杂区传输的电子或空穴;所述第二电极结构用于收集沿所述吸收结构及所述第二掺杂区传输的电子或空穴。
- 根据权利要求2所述的光电探测器,其中,所述光电探测器还包括位于所述第一掺杂区与所述第二掺杂区之间的本征区,其中,所述本征区的材料与所述限光结构的材料相同;或者,所述本征区的材料与所述吸收结构的材料相同。
- 根据权利要求2所述的光电探测器,其中,所述光电探测器还包括位于所述第一掺杂区与所述第二掺杂区之间沿所述限光结构厚度的方向依次层叠设置的第一本征区、第二本征区,其中,所述第一本征区的材料与所述限光结构的材料相同;所述第二本征区的材料与所述吸收结构的材料相同。
- 根据权利要求3或4所述的光电探测器,其中,所述第一掺杂区、所述本征区及所述第二掺杂区在预设平面的投影之和覆盖所述吸收结构在所述预设平面的投影;所述吸收结构在所述预设平面的投影覆盖所述本征区在所述预设平面的投影;其中,所述预设平面垂直于所述限光结构厚度的方向。
- 根据权利要求2所述的光电探测器,其中,所述第一电极结构包括第一电极、第一电极接触区以及第三掺杂区;其中,所述第三掺杂区位于所述第一掺杂区内侧且与所述第一掺杂区接触;所述第一电极接触区位于所述第三掺杂区表面及向下一定深度的区域,所述第一电极位于所述第一电极接触区之上;所述第一电极用于收集依次沿所述吸收结构、第一掺杂区、所述第三掺杂区以及所述第一电极接触区传输的电子或空穴;所述第二电极结构包括第二电极、第二电极接触区以及第四掺杂区;其中,所述第四掺杂区包围所述限光结构,所述第二电极接触区位于所述第四掺杂区表面及向下一定深度的区域,所述第二电极位于所述第二电极接触区之上;所述第二电极用于收集依次沿所述吸收结构、所述第二掺杂 区及所述第四掺杂区传输的电子或空穴。
- 根据权利要求6所述的光电探测器,其中,所述第二掺杂区的掺杂浓度小于等于所述第四掺杂区的掺杂浓度,所述第四掺杂区的掺杂浓度小于所述第二电极接触区的掺杂浓度;所述第一掺杂区的掺杂浓度小于等于所述第三掺杂区的掺杂浓度,所述第三掺杂区的浓度小于所述第一电极接触区的掺杂浓度。
- 根据权利要求6所述的光电探测器,其中,所述第一电极接触区远离所述吸收结构,且所述第三掺杂区的厚度小于等于所述限光结构的厚度;所述波导结构的厚度与所述限光结构的厚度相同。
- 根据权利要求1所述的光电探测器,其中,所述波导结构在预设平面的投影的形状包括长条状;所述限光结构的外侧壁在所述预设平面的投影的形状包括由至少一段直线和/或至少一段曲线形成的封闭图形,且所述限光结构的外侧壁中的第二侧壁所在的第二边和外侧壁中第三侧壁所在的第三边形成的角度为钝角;其中,所述第三侧壁为所述入射光进入所述限光结构后第一次发生反射处的侧壁。
- 根据权利要求9所述的光电探测器,其中,所述限光结构的外侧壁在所述预设平面的投影的形状包括以下之一:圆形;多段曲线连接形成的封闭形状;多段直线和多段曲线连接形成的封闭形状;多边形。
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