CN118016748A - Single-row carrier photodetector - Google Patents
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Abstract
The present invention provides a single row carrier photodetector comprising: the device comprises a first electrode contact layer, an electron collecting layer, a cliff layer, an absorption layer, an electron diffusion barrier layer, a second electrode contact layer, an optical scattering structure and an optical film layer, wherein the first electrode contact layer, the electron collecting layer and the cliff layer are sequentially arranged above a semiconductor material substrate; the optical thin film layer forms an upper cladding layer of the waveguide structure, the electron collecting layer forms a lower cladding layer of the waveguide structure, the optical scattering structure is used for scattering incident light from a vertical incidence direction, and part of scattered light is coupled into the waveguide structure formed by the single-row carrier photodetector to carry out transverse propagation, so that the propagation distance of the incident light in the absorption layer is increased. The single-row carrier photodetector provided by the invention can effectively improve the responsivity of the single-row carrier photodetector.
Description
Technical Field
The invention relates to the technical field of optical detection equipment, in particular to a single-row carrier optical detector.
Background
In RoF systems (radio-over-fiber radio-on-optical communication systems), a photodetector with a higher response rate and a higher output power is required to support the increase in the frequency of millimeter wave signals and the increase in information capacity. The single-row carrier photodetector (UTC-PD) only allows high-speed electrons to serve as carriers, so that the transit time of the carriers can be effectively shortened, the bandwidth and saturation current of the detector can be obviously improved, and the detector is applied to a base station of a RoF system, not only simplifies the system constitution, but also is easy for integrating the photodetector and an antenna. However, there is a conflict between bandwidth and quantum efficiency in single-row carrier photodetectors. Increasing the quantum efficiency means increasing the thickness of the absorber layer, which increases the transit time of the photogenerated electrons due to the diffusion motion of the electrons within the absorber layer, resulting in a decrease in the response speed of the single-row carrier photodetector. The RoF technology as a key technology for solving the problem of the last kilometer puts higher requirements on an optical receiving terminal, and a single-row carrier optical detector with high bandwidth and high responsivity has become an important point of research.
Disclosure of Invention
The invention provides a single-row carrier photodetector, which is used for solving the defect that the design limitation of the photodetector in the prior art is higher, so that the response speed is poor.
The present invention provides a single row carrier photodetector comprising: the device comprises a first electrode contact layer arranged above a preset semiconductor material substrate, an electron collecting layer arranged above the first electrode contact layer, a cliff layer arranged above the electron collecting layer, an absorbing layer arranged above the cliff layer, an electron diffusion barrier layer arranged above the absorbing layer, a second electrode contact layer arranged above the electron diffusion barrier layer, an optical scattering structure arranged above the second electrode contact layer and an optical film layer arranged above the optical scattering structure, wherein the first electrode contact layer is arranged above the preset semiconductor material substrate; the optical thin film layer forms an upper cladding layer of the waveguide structure, the electron collecting layer forms a lower cladding layer of the waveguide structure, the optical scattering structure is used for scattering incident light from a vertical incidence direction, and part of scattered light is coupled into the waveguide structure formed by the single-row carrier photodetector to be transmitted transversely, so that the transmission distance of the incident light in the absorption layer is increased.
Further, the optical scattering structure is composed of an array of a plurality of individual scattering particles; wherein the shape of the scattering particles comprises a sphere, a cube or a cylinder; the scattering particles have a pitch size of between 0.1 μm and 4 μm.
Further, the optical scattering structure is composed of an array of a plurality of etch pits; wherein the shape of the etch pit comprises a circle or square; the depth of the etch pits is between 0.1 μm and 0.5 μm, the radius or side length of the etch pits is between 0.1 μm and 1 μm, and the pitch size of the etch pits is between 0.1 μm and 4 μm.
Further, the optical film layer is a dielectric film or a semiconductor material layer.
Further, the surface of the optical film layer is covered with a metal reflecting layer, a Bragg reflector layer or a reflecting structure layer formed by the metal reflecting layer and the Bragg reflector.
Further, the absorption layer is formed by a p-type doped semiconductor material; or on a hybrid absorber layer composed of a combination of a non-intentionally doped semiconductor material and a p-type doped semiconductor material.
Further, the single-row carrier photodetector further includes: a P electrode disposed on the first electrode contact layer and an N electrode disposed on the second electrode contact layer; the first electrode contact layer is electrically connected with the P electrode, and the second electrode contact layer is electrically connected with the N electrode.
Further, the electron diffusion barrier layer is used for blocking electrons from diffusing to the P electrode so as to diffuse the electrons to the aggregation layer.
Further, the electron collecting layer is used for collecting electrons generated by the absorbing layer.
Further, a sub-collecting layer is further disposed between the electron collecting layer and the first electrode contact layer.
The invention provides a single-row carrier photodetector, which comprises a first electrode contact layer arranged above a preset semiconductor material substrate, an electron collecting layer arranged above the first electrode contact layer, a cliff layer arranged above the electron collecting layer, an absorbing layer arranged above the cliff layer, an electron diffusion barrier layer arranged above the absorbing layer, a second electrode contact layer arranged above the electron diffusion barrier layer, an optical scattering structure arranged above the second electrode contact layer and an optical film layer arranged above the optical scattering structure, wherein the first electrode contact layer is arranged above the preset semiconductor material substrate; the optical thin film layer forms an upper cladding layer of the waveguide structure, the electron collecting layer forms a lower cladding layer of the waveguide structure, the optical scattering structure is used for scattering incident light from a vertical incidence direction, and part of scattered light is coupled into the waveguide structure formed by the single-row carrier photodetector to be transmitted transversely, so that the transmission distance of the incident light in the absorption layer is increased. The design can utilize the scattering property of particles to convert incident light from normal incidence to transverse propagation, and the scattered light is restrained in an absorption layer by the waveguide structure, so that the responsivity of the single-row carrier photodetector is improved under the condition of thinner absorption layer thickness.
Drawings
In order to more clearly illustrate the invention or the technical solutions of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the invention, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a single row carrier photodetector according to the present invention;
FIG. 2 is a schematic diagram of a single-row carrier photodetector according to a second embodiment of the present invention;
FIG. 3 is a third schematic diagram of a single-row carrier photodetector according to the present invention;
FIG. 4 is a schematic diagram of a single-row carrier photodetector according to the present invention;
FIG. 5 is a schematic diagram of a single-row carrier photodetector according to the present invention;
FIG. 6 is a schematic diagram of a single-row carrier photodetector according to the present invention;
FIG. 7 is a schematic diagram of a single-row carrier photodetector according to the invention;
Wherein 1 is a P electrode; 2 is an optical film layer; 3 is an optical scattering structure (scattering particles or etch pits); 4 is a first electrode contact layer (i.e., P-type contact layer); 5 is a diffusion barrier (i.e., an electron diffusion barrier); 6 is an absorption zone; 7 is a spacer layer; 8 is a cliff layer; 9 is an electron collecting layer; 10 is a sub-collection layer; 11 is a second electrode contact layer (i.e., N-type contact layer); 12 is an N electrode.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that the terms "first," "second," and the like in the description of the present invention and the above-described figures are used for distinguishing between similar users and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The invention provides a single-row carrier photodetector combined with a nanoscale optical microstructure aiming at the single-row carrier photodetector. By designing the optical scattering structures (i.e., scattering structures) and the waveguide structures in the device, the incident light is converted from normal incidence to lateral propagation while the scattered light is confined within the absorbing layer. For a single-row carrier photodetector, the width of the absorption layer is much larger than the thickness, so that the responsivity of the single-row carrier photodetector is improved.
Embodiments of the single-row carrier photodetector according to the present invention will be described in detail below. As shown in fig. 1, which is one of the schematic structural diagrams of the single-row carrier photodetector provided by the invention, the specific implementation process includes the following parts: the device comprises a first electrode contact layer arranged above a preset semiconductor material substrate, an electron collecting layer arranged above the first electrode contact layer, a cliff layer arranged above the electron collecting layer, an absorbing layer arranged above the cliff layer, an electron diffusion barrier layer arranged above the absorbing layer, a second electrode contact layer arranged above the electron diffusion barrier layer, an optical scattering structure arranged above the second electrode contact layer and an optical film layer arranged above the optical scattering structure. Specifically, the first electrode contact layer may be an n-type high doping concentration (> 1 x 10 18/cm3) electrode contact layer located on a semiconductor material substrate; the electron collecting layer may be an unintentionally doped electron collecting layer on the first electrode contact layer, the electron collecting layer being for collecting electrons generated by the absorbing layer; the cliff layer can be an n-type doped cliff layer for adjusting an electric field; the absorption layer can be formed by p-type doped semiconductor material on the cliff layer; or a mixed absorption layer formed by semiconductor materials which are not specially doped and p-type doped, wherein the absorption layer or the mixed absorption layer is a core layer of a waveguide structure and is used for transmitting scattered light; the electron diffusion barrier layer may be a p-type doped electron diffusion barrier layer on the absorber layer, which may be used to block the diffusion of electrons to the p-electrode such that electrons only diffuse to the collector layer. The second electrode contact layer may be a p-type high doping concentration (> 6 x 10 18/cm3) electrode contact layer located on the electron diffusion barrier layer. The optical thin film layer forms an upper cladding layer of the waveguide structure, the electron collecting layer forms a lower cladding layer of the waveguide structure, the optical scattering structure is used for scattering incident light from a vertical incidence direction, and part of scattered light is coupled into the waveguide structure formed by the single-row carrier photodetector to be transmitted transversely, so that the transmission distance of the incident light in the absorption layer is increased. In addition, a sub-collecting layer is arranged between the electron collecting layer and the first electrode contact layer, and the sub-collecting layer is mainly used for buffering between the electron collecting layer and the n-type contact layer because the doping concentration difference between the electron collecting layer and the n-type contact layer is relatively large. The electron collecting layer and the sub-collecting layer are used for collecting electrons generated by the absorbing layer. Further, the single-row carrier photodetector further comprises a P electrode arranged on the first electrode contact layer and an N electrode arranged on the second electrode contact layer for contact; the first electrode contact layer is electrically connected with the P electrode, and the second electrode contact layer is electrically connected with the N electrode for contact.
In an embodiment of the invention, the top layer of the single row carrier photodetector is provided with an optical scattering structure, which is formed by an array of a plurality of individual scattering particles, which may be periodic or aperiodic. Wherein the shape of the scattering particles comprises sphere, cube or cylinder, and the material of the scattering particles comprises but is not limited to Ge, ag, au, cu, al, siO 2, si, and the like; the scattering particles have a pitch size of between 0.1 μm and 4 μm. Each scattering particle serves as a sub-light source, and incident light is scattered by the scattering particles to form a waveguide effect. The size of the scattering particles is different for particles of different shapes, the radius of the spherical particles is between 0.1 μm and 2 μm, the radius of the cylindrical particles is between 0.1 μm and 2 μm, the height is between 0.1 μm and 2 μm, the side length of the stereoscopic particles is between 0.1 μm and 2 μm, etc. The particle spacing can be equal or unequal, and the size of the spacing is between 0.1 and 4 mu m, and different optimal values can be obtained according to different particle materials and shapes. In addition, the optical scattering structure may be an array of a plurality of etch pits, which may or may not be periodic. Wherein the shape of the etching pit comprises a round shape or a square shape, and the material of the etching layer comprises, but is not limited to, inP, inGaAsP and the like; the depth of the etch pits is between 0.1 μm and 0.5 μm, the radius or side length of the etch pits is between 0.1 μm and 1 μm, and the pitch size of the etch pits is between 0.1 μm and 4 μm.
The optical film layer can be a dielectric film or a semiconductor material layer, and can be made of SiO 2、Si3N4, niO and the like as an upper cladding of the device waveguide structure, and the thickness of the optical film layer is 300nm to 3000nm, and different optimal values can be obtained according to different optical film constituent materials and optical scattering structures. The surface of the optical film layer can be covered with a metal reflecting layer, a Bragg reflector layer or a reflecting structure layer formed by the metal reflecting layer (namely a DBR reflector) and the Bragg reflector. The absorption layer is formed by a semiconductor material based on p-type doping; or on a hybrid absorber layer composed of a combination of a non-intentionally doped semiconductor material and a p-type doped semiconductor material. GaAs can be used as a material of an absorption layer of the short wavelength detector, n-type doped AlGaAs can be used as a material of a collecting layer, n-type doped (1 x 10 17/cm3) AlGaAs can be used as a material of a cliff layer, and p-type doped AlGaAs can be used as a material of a blocking layer. InGaAs can be used as the material of the absorption layer of the long wavelength detector, n-type doped InGaAsP, inP or InAlGaAs can be used as the material of the collection layer, n-type doped InP (1 x 10 17/cm3) can be used as the material of the cliff layer, and p-type doped InGaAsP can be used as the material of the barrier layer. GaAsSb may be used as the material of the absorption layer of the mid-distance detector, n-type doped InP may be used as the material of the collection layer, and p-type doped AlGaAsSb may be used as the material of the barrier layer. The thickness of the collecting layer is 300nm to 3000nm, the thickness of the absorbing layer is 100nm to 1000nm, the thickness of the blocking layer is 20nm to 70nm, the thickness of the cliff layer is 20nm to 100nm, and different optimal values are realized according to different layer structure materials and different optical scattering structures.
The single-row carrier detector provided by the invention is UTC-PD combined with a nanoscale optical microstructure, and aims to obtain higher responsivity under a thinner absorption layer, and has the requirements of high bandwidth and high responsivity. By designing the optical scattering structure and the waveguide structure of the device, the effect similar to that of the waveguide type photodetector is achieved under the condition of normal incidence, and meanwhile, the problem of coupling efficiency of the waveguide type photodetector is avoided. As shown in fig. 6 and 7, which are schematic views of the overall structure of the single row carrier detector, normal incidence and back incidence respectively.
In particular, in the structure of the single row carrier detector, the diameter of the active region may be between 10 μm and 30 μm, and the thickness of the collecting layer may be between 300nm and 3000 nm. For the short wavelength detector corresponding to the single-row carrier detector, the material of the collecting layer can be n-type doped AlGaAs. For long wavelength detectors, the material of the collection layer may be n-doped InGaAsP, inP or InAlGaAs, etc. For the mid-far detector corresponding to the single-row carrier detector, the collecting layer may be made of n-doped InP. Preferably, the semiconductor material substrate is made of InGaAsP material, and the collecting layer is made of InGaAsP with a refractive index difference from InP of the semiconductor material substrate, and the InGaAsP refractive index is lower than InGaAs, so that the lower cladding of the monolithic waveguide structure can be formed. The thickness of the absorption layer in the single row carrier detector structure may be between 100nm and 1000nm as the core layer of the overall waveguide structure. For short wavelength detectors, gaAs may be used as the material for the absorber layer. For long wavelength detectors, inGaAs may be used as the material of the absorption layer. For the mid-distance detector, gaAsSb can be used as the material of the absorber layer.
The single row carrier detector structure further comprises a p-type contact layer (i.e. a first electrode contact layer), an electron diffusion barrier layer, a spacer layer, a cliff layer, a sub-collector layer and an n-type contact layer (i.e. a second electrode contact layer). For the short wavelength detector, the cliff layer may be made of n-type high doped (1×10 18/cm3) AlGaAs, and the barrier layer may be made of p-type doped AlGaAs. For long wavelength detectors, the cliff layer material may be n-type highly doped (> 1 x 10 18/cm3) InP and the barrier layer material may be p-type doped InGaAsP. For the mid-distance detector, the barrier layer material may be p-type doped AlGaAsSb.
In the single-row carrier detector structure, an optical film layer, which can be a dielectric film, is coated on the top layer of the device, and the material can be SiO 2、Si3N4, niO and the like. Since these materials have a lower refractive index than the material of the absorption layer, the upper cladding layer of the waveguide can be constituted.
In the single-row carrier detector structure, the thickness of the top-layer optical film can be 300nm to 3000nm, and different optimal values can be obtained according to different dielectric film materials and optical scattering structures. The optical film layer may be covered with a metal reflective layer or DBR mirror or two reflective structures. In the single-row carrier detector structure, an optical scattering structure is arranged in an optical film at the top of the device, the optical scattering structure consists of an array of scattering particles, and the shape of the scattering particles can be spherical, cubic, cylindrical and the like. In the single row carrier detector structure, materials of scattering particles include, but are not limited to, ge, ag, au, cu, al, siO 2, si, and the like. Preferably, in the optical scattering structure of the single-row carrier detector structure, the size of the scattering particles has different values for particles of different shapes, the radius for spherical particles is between 0.1 μm and 2 μm, the radius for columnar particles is between 0.1 μm and 2 μm, the height is between 0.1 μm and 2 μm, the side length of the cubic particles is between 0.1 μm and 2 μm, etc. The particle spacing can be equal or unequal, and the size of the spacing is between 0.1 and 4 mu m, and different optimal values can be obtained according to different particle materials and shapes. The invention uses the scattering of particles to convert the incident light from vertical incidence to transverse transmission, and then the scattered light is restrained in the absorption layer by the design of the device layer structure, so that the invention can have higher responsivity under the condition of thinner absorption layer thickness.
It should be noted that, the basic concepts of the present invention are illustrated in fig. 1-4 provided in the embodiments of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings, rather than the number, shape and size of the components in actual implementation, and the form, number and proportion of each component in actual implementation may be arbitrarily changed, and the layout of the components may be more complex. FIG. 1 is a schematic diagram of a single-row carrier detector in the present embodiment, which is back-incident, and the optical scattering structures are scattering particles; FIG. 2 is a schematic diagram showing a single-row carrier detector with normal incidence and scattering particles as the optical scattering structure according to the present invention; FIG. 3 shows a schematic structure of a single row carrier detector in the case of the present invention, which is back-incident, and the scattering structure is etch pits; fig. 4 shows a schematic structure of a single row carrier detector in the case of the present invention, which is normal incidence, and the scattering structure is a corrosion pit.
In the following detailed examples, the optical thin film layer may be composed of 800nm SiO 2 material, the optical scattering structure may be cylindrical particles, the radius may be 0.4 μm, the height may be 0.4 μm, the period may be 1.4 μm, and the material may be Si, in particular, when the single-row carrier detector of the present invention is an embodiment for a short wavelength detector; the p-type contact layer can be made of 500nm AlGaAs material, and the doping concentration can be 1x1018/cm3; the absorption layer can be made of 140nm GaAs material, the doping concentration can be 1x10 19/cm3 to 5 x10 17/cm3 gradient doping, the cliff layer can be made of 70nm InP material, and the doping concentration can be 5 x10 18/cm3; the collecting layer is made of 300nm AlGaAs material, and the doping concentration is 3 x10 16/cm3; the n-type contact layer is made of 300nm AlGaAs material, and the doping concentration is 1x10 19/cm3.
Specifically, when the single-row carrier detector is a pair-long wavelength detector, the optical film layer can be made of a NiO material with the wavelength of 1500nm, the scattering structure is spherical particles, the radius is 0.7 mu m, the period is 1.9 mu m, and the material is Ge; the p-type contact layer is made of 50nm InGaAs material, and the doping concentration is 2 x10 19/cm3; the electron diffusion barrier layer is made of an InGaAsP material with the thickness of 20nm and the doping concentration is 1x10 19/cm3; the absorption layer is made of 200nm InGaAs material, and the doping concentration is 5x 10 18/cm3 to 3 x10 17/cm3 Gaussian doping; the spacer layer is made of an InGaAsP material with the thickness of 13nm and the doping concentration is 1x10 15/cm3; the cliff layer is made of 70nm InP material, and the doping concentration is 1x10 18/cm3; the electron collecting layer (namely the collecting layer) is made of an InGaAsP material with 1500nm and the doping concentration is 1x10 15/cm3; the sub-collecting layer is made of an InGaAsP material with the thickness of 70nm and the doping concentration is 1x10 18/cm3; the n-type contact layer is made of 500nm InGaAsP material, and the doping concentration is 1x10 19/cm3.
Specifically, when the single-row carrier detector is a long-wavelength detector, the optical film layer is composed of 1000nm SiO 2 material, the optical scattering structure is composed of an array composed of a plurality of corrosion pits, the material of the corrosion pits is InGaAsP, the depth is 0.2 μm, the shape is round, the radius is 0.5 μm, and the period is 2 μm; the p-type contact layer is made of 50nm InGaAs material, and the doping concentration is 2 x 10 19/cm3; the electron diffusion barrier layer is made of an InP material with the thickness of 50nm, and the doping concentration is 1 x 10 19/cm3; the absorption layer is made of an InGaAs material with 1500nm, and the doping concentration is 5-10 18/cm3 -3-10 17/cm3 Gauss doping; the spacer layer is made of InAlAs material with the thickness of 20nm and the doping concentration is 1 x 10 15/cm3; the cliff layer is made of 70nm InAlAs material, and the doping concentration is 1 x 10 18/cm3; the electron collecting layer is made of 500nm InAlGaAs material, and the doping concentration is 1 x 10 15/cm3; the sub-collecting layer is made of 70nm InAlAs material, and the doping concentration is 1 x 10 18/cm3; the n-type contact layer is made of an InP material with the thickness of 500nm and the doping concentration is 1 x 10 19/cm3.
Specifically, when the single-row carrier detector is a mid-far infrared detector, the optical film layer is composed of 1000nm Si 3N4 material, the scattering structure is cube-shaped particles, the length and width are 0.6 μm, the height is 0.5 μm, the period is 1.6 μm, and the material is Ag; the p-type contact layer is made of an InGaAs material with the thickness of 100nm, and the doping concentration is 2 x 10 19/cm3; the electron diffusion barrier layer is made of 50nm AlGaAsSb material, and the doping concentration is 1 x 10 19/cm3; the absorption layer is made of a GaAsSb material with the thickness of 200nm and the doping concentration is 5 x 10 18/cm3; the collecting layer is made of 400nm InP material, and the doping concentration is 1 x 10 15/cm3; the n-type contact layer is made of 300nm InP material, and the doping concentration is 1 x 10 19/cm3.
In summary, in several specific embodiments, the responsivity of the single-row carrier detector of the present invention is improved by about 10% to 50% compared to the case without the scattering structure, and the improvement effect is different according to different device layer structures and scattering structures. Specifically, a process manufacturing flow of the scattering structure of the single-row carrier detector is to coat photoresist on the surface of a device, then expose and develop a circle with a certain size through a EBL (electron beam lithography) photoetching machine, then coat a metal material, and finally wash off the photoresist to obtain a metal column with a corresponding size. Fig. 5 is a schematic diagram showing the layer structure and principle of the single-row carrier detector. The incident light is converted from vertical incidence to transverse transmission, the absorption layer is used as a core, the collection layer and the top layer are used as upper and lower cladding layers to form a waveguide structure, scattered light can be confined in the absorption layer, scattering particles on the top are equivalent to a plurality of sub-wave sources, and the structure ensures that the electron transmission characteristics are not changed, but the transmission distance of the light in the absorption layer is improved. For the single-row carrier detector, the width of the absorption layer is much larger than the thickness, so that the responsivity can be improved. And since it is of a vertical incidence type, there is no problem of low coupling efficiency of the waveguide coupling type photodiode.
As shown in fig. 6 and 7, the single row carrier detector is shown schematically in its overall structure, in the case of normal incidence and back incidence, respectively. The single-row carrier detector structure combined with the nano-scale optical microstructure has the following effects: the scattering of the particles is utilized to convert incident light from normal incidence into transverse propagation, and the waveguide structure of the device is utilized to ensure that the scattered light is confined in the absorption layer, so that the propagation distance of the light in the absorption layer is increased, and the responsivity of the device is improved.
The invention provides a single-row carrier photodetector, which comprises a first electrode contact layer arranged above a preset semiconductor material substrate, an electron collecting layer arranged above the first electrode contact layer, a cliff layer arranged above the electron collecting layer, an absorbing layer arranged above the cliff layer, an electron diffusion barrier layer arranged above the absorbing layer, a second electrode contact layer arranged above the electron diffusion barrier layer, an optical scattering structure arranged above the second electrode contact layer and an optical film layer arranged above the optical scattering structure, wherein the first electrode contact layer is arranged above the preset semiconductor material substrate; the optical thin film layer forms an upper cladding layer of the waveguide structure, the electron collecting layer forms a lower cladding layer of the waveguide structure, the optical scattering structure is used for scattering incident light from a vertical incidence direction, and part of scattered light is coupled into the waveguide structure formed by the single-row carrier photodetector to be transmitted transversely, so that the transmission distance of the incident light in the absorption layer is increased. The design can utilize the scattering property of particles to convert incident light from normal incidence to transverse propagation, and the scattered light is restrained in an absorption layer by the waveguide structure, so that the responsivity of the single-row carrier photodetector is improved under the condition of thinner absorption layer thickness.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A single row carrier photodetector, comprising: the device comprises a first electrode contact layer arranged above a preset semiconductor material substrate, an electron collecting layer arranged above the first electrode contact layer, a cliff layer arranged above the electron collecting layer, an absorbing layer arranged above the cliff layer, an electron diffusion barrier layer arranged above the absorbing layer, a second electrode contact layer arranged above the electron diffusion barrier layer, an optical scattering structure arranged above the second electrode contact layer and an optical film layer arranged above the optical scattering structure, wherein the first electrode contact layer is arranged above the preset semiconductor material substrate;
The optical thin film layer forms an upper cladding layer of the waveguide structure, the electron collecting layer forms a lower cladding layer of the waveguide structure, the optical scattering structure is used for scattering incident light from a vertical incidence direction, and part of scattered light is coupled into the waveguide structure formed by the single-row carrier photodetector to be transmitted transversely, so that the transmission distance of the incident light in the absorption layer is increased.
2. The single row carrier photodetector of claim 1, wherein said optical scattering structure is comprised of an array of a plurality of individual scattering particles; wherein the shape of the scattering particles comprises a sphere, a cube or a cylinder; the scattering particles have a pitch size of between 0.1 μm and 4 μm.
3. The single row carrier photodetector of claim 1, wherein said optical scattering structure is comprised of an array of a plurality of etch pits; wherein the shape of the etch pit comprises a circle or square; the depth of the etch pits is between 0.1 μm and 0.5 μm, the radius or side length of the etch pits is between 0.1 μm and 1 μm, and the pitch size of the etch pits is between 0.1 μm and 4 μm.
4. The single row carrier photodetector of claim 1, wherein said optical thin film layer is a dielectric film or a semiconductor material layer.
5. The single row carrier photodetector of claim 4 wherein said optical film layer surface is covered with a metal reflective layer, a bragg mirror layer or a reflective structure layer comprised of both said metal reflective layer and said bragg mirror.
6. The single row carrier photodetector of claim 1, wherein said absorber layer is an absorber layer based on a p-doped semiconductor material; or on a hybrid absorber layer composed of a combination of a non-intentionally doped semiconductor material and a p-type doped semiconductor material.
7. The single row carrier photodetector of claim 1, further comprising: a P electrode disposed on the first electrode contact layer and an N electrode disposed on the second electrode contact layer; the first electrode contact layer is electrically connected with the P electrode, and the second electrode contact layer is electrically connected with the N electrode.
8. The single row carrier photodetector of claim 1, wherein said electron diffusion barrier is adapted to block diffusion of electrons to the P electrode such that electrons diffuse to the collector layer.
9. The single row carrier photodetector of claim 1, wherein said electron collecting layer is adapted to collect electrons generated by the absorbing layer.
10. The single row carrier photodetector of claim 1, wherein a sub-collection layer is further disposed between said electron collection layer and said first electrode contact layer.
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| CN202410030541.2A CN118016748A (en) | 2024-01-09 | 2024-01-09 | Single-row carrier photodetector |
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