Semiconductor photoelectric detector and preparation method thereof

Abstract

The invention relates to the technical field of photoelectric detection, and provides a semiconductor photoelectric detector and a preparation method thereof, the detector comprises a functional layer, an absorption layer, a first doping layer and a second doping layer, the absorption layer is located on a part of the surface of the functional layer, and the absorption layer has a first side surface and a second side surface which are opposite; the first doping layer is located on the first side surface of the functional layer and the first side surface of the absorption layer; the second doping layer is located on the second side surface of the functional layer, the second side surface of the absorption layer and the surface of the absorption layer away from the functional layer; a preset distance is formed between the first doping layer and the second doping layer; the doping types of the first doping layer and the second doping layer are different. According to the semiconductor photoelectric detector, the first doping layer adopts an L-shaped doping structure, the second doping layer adopts a Z-shaped doping structure, P + and N + ohmic contact regions are formed, a carrier transport path is optimized, the transit time of carriers is effectively shortened, the working bandwidth of a device is improved, and the semiconductor photoelectric detector can be applied to high-speed photoelectric detection.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic detection technology, and particularly to a semiconductor optoelectronic detector and a preparation method thereof. Background Art

[0002] With the rapid development of the information technology field, multiple technologies including artificial intelligence, optical computing, and big data are undergoing rapid iteration, resulting in an exponential growth of the global data volume, posing unprecedented challenges to the real-time transmission capacity, ultra-large-scale storage, and high-efficiency computing capacity of information systems. In this context, as one of the core components of optoelectronic systems, the performance of high-speed detectors is crucial for realizing efficient optical signal-to-electrical signal conversion. In recent years, the development and innovation of silicon-based optoelectronic technology and heterogeneous integration technology have laid the foundation for the large-scale application of high-speed detectors in fields such as optical interconnection in data centers, intelligent sensing networks, and remote medical imaging. With the deep integration of optoelectronic fusion architectures and heterogeneous integration technology, high-speed detectors will continue to empower the upgrade of information infrastructure in the intelligent era in more dimensions.

[0003] The bandwidth of high-speed detectors is mainly affected by the RC constant and the carrier transit time. Currently, for detectors with a horizontally transmitted optical field and a left-right distributed electrode structure, the carrier transit time of the conventional doping structure is limited by the detector width. When the height of this structure detector is fixed, its width is affected by the working wavelength and the material refractive index. Therefore, when the device size is fixed, reducing the carrier transport time can effectively improve the detector bandwidth. Summary of the Invention

[0004] The present invention provides a semiconductor optoelectronic detector and a preparation method thereof to solve the problem that in the prior art, in the left-right electrode structure, the bandwidth of high-speed detectors is affected by the device width. This detector structure can shorten the carrier transport time, thereby improving the detector bandwidth to meet the growing data processing requirements.

[0005] The present invention provides a semiconductor optoelectronic detector, comprising: Functional layer; Absorption layer, located on a partial surface of the functional layer, the absorption layer having a first side and a second side opposite to each other along a first direction; First doping layer, the first side of the first doping layer is located on the first side surface of the functional layer, and the second side of the first doping layer is located on the first side of the absorption layer; A second doped layer, the middle part of the second doped layer is located on the second side of the absorption layer, the first side of the second doped layer is located on the second side surface of the functional layer, and the second side of the second doped layer is located on the surface of the absorption layer away from the functional layer; one end of the first doped layer close to the second doped layer has a preset distance from one end of the second doped layer close to the first doped layer along a first direction; the doping types of the first doped layer and the second doped layer are different.

[0006] According to a semiconductor photodetector provided by the present invention, the first doped layer includes a first doped sub-region and a second doped sub-region connected to each other. The first doped sub-region is located on the first side surface of the functional layer, the second doped sub-region is located on the first side of the absorption layer, and the peak doping depth of the first doped sub-region is greater than the peak doping depth of the second doped sub-region.

[0007] According to a semiconductor photodetector provided by the present invention, the peak doping depth of the first doped sub-region is less than 200 nm, and / or the doping concentration of the first doped sub-region is 1×10 18 ~9×10 19 cm³.

[0008] According to a semiconductor photodetector provided by the present invention, the peak doping depth of the second doped sub-region is 20 - 100 nm, and / or the doping concentration of the second doped sub-region is 1×10 18 ~9×10 19 cm³.

[0009] According to a semiconductor photodetector provided by the present invention, the second doped layer includes a third doped sub-region, a fourth doped sub-region, and a fifth doped sub-region connected in sequence; The third doped sub-region is located on the second side surface of the functional layer, the fourth doped sub-region is located on the second side of the absorption layer, the fifth doped sub-region is located on the surface of the absorption layer away from the functional layer, the peak doping depth of the third doped sub-region is greater than the peak doping depth of the fourth doped sub-region, and the peak doping depth of the third doped sub-region is greater than the peak doping depth of the fifth doped sub-region.

[0010] According to a semiconductor photodetector provided by the present invention, the peak doping depth of the second doped sub-region is equal to the peak doping depth of the fourth doped sub-region.

[0011] According to a semiconductor photodetector provided by the present invention, the thickness of the absorption layer is less than the width of the absorption layer.

[0012] According to a semiconductor photodetector provided by the present invention, the preset distance is greater than 50 nm.

[0013] A semiconductor photodetector provided by the present invention, the functional layer includes: a substrate; a buffer layer disposed on the substrate; The absorption layer is disposed in the middle region of the surface of the buffer layer facing away from the substrate, and the first sides of the first doping layer and the second doping layer are located on the surface of the buffer layer.

[0014] A semiconductor photodetector provided by the present invention, the functional layer includes: a substrate; a buffer layer disposed in the middle region of the substrate; The absorption layer is disposed on the surface of the buffer layer facing away from the substrate, and the first sides of the first doping layer and the second doping layer are both located on the side surface of the buffer layer and the surface of the substrate.

[0015] A semiconductor photodetector provided by the present invention, the functional layer includes a substrate, the absorption layer is disposed in the middle region of the substrate, and the first sides of the first doping layer and the second doping layer are located on the surface of the substrate.

[0016] The present invention also provides a method for manufacturing a semiconductor photodetector, including the following steps: forming an absorption layer on a part of the surface of the functional layer; forming a first doping layer on the first side surface of the absorption layer and the first side surface of the functional layer; forming a second doping layer on the second side surface of the functional layer, the second side surface of the absorption layer, and the surface of the absorption layer away from the functional layer; one end of the first doping layer close to the second doping layer and one end of the second doping layer close to the first doping layer have a preset distance along the first direction; the doping types of the first doping layer and the second doping layer are different.

[0017] In the semiconductor photodetector provided by the present invention, by adopting an "L"-shaped doping structure formed on the first side surface of the absorption layer and the first side surface of the functional layer for the first doping layer, and an "S"-shaped doping structure formed on the second side surface of the functional layer, the second side surface of the absorption layer, and the surface of the absorption layer away from the functional layer for the second doping layer, a P + and N + Ohmic contact region is formed to optimize the carrier transport path, effectively shorten the carrier transit time, thereby improving the working bandwidth of the device, and being applicable to high-speed photodetection applications. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic structural diagram of a semiconductor photodetector provided by the present invention.

[0020] Figure 2 It is one of the schematic structural diagrams of the functional layer and the absorption layer provided by the present invention.

[0021] Figure 3 It is the second schematic structural diagram of the functional layer and the absorption layer provided by the present invention.

[0022] Figure 4 It is the third schematic structural diagram of the functional layer and the absorption layer provided by the present invention.

[0023] Figure 5 It is a schematic flow diagram of the preparation method of the semiconductor photodetector provided by the present invention.

[0024] Figure 6 It is a schematic diagram of the normalized response characteristics of a conventional doped Si waveguide evanescent wave coupled Ge photodetector and the photodetector of the present invention at different frequencies.

[0025] Reference numerals: 100, functional layer; 110, substrate; 120, buffer layer; 101, first side surface; 102, second side surface; 200, absorption layer; 210, first side; 220, second side; 230, upper surface of the absorption layer; 300, first doping layer; 310, first doping sub-region; 320, second doping sub-region; 400, second doping layer; 410, third doping sub-region; 420, fourth doping sub-region; 430, fifth doping sub-region; 510, first electrode; 520, second electrode; 600, passivation layer. Detailed implementation manners

[0026] To make the objectives, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the embodiments of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0028] In the description of the embodiments of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0029] In the embodiments of the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0030] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0031] The following will describe Figures 1-4 the semiconductor photodetector of the present invention.

[0032] An embodiment of the present invention provides a semiconductor photodetector, as Figures 1 to 4 shown, the semiconductor photodetector includes a functional layer 100, an absorption layer 200, a first doping layer 300, and a second doping layer 400.

[0033] Among them, the absorption layer 200 is located on a part of the surface of the functional layer 100, and the absorption layer 200 has a first side surface 210 and a second side surface 220 opposite to each other in a first direction; the first doping layer 300 is located on the first side surface 210 of the absorption layer 200 and the first side surface 101 of the functional layer 100, and the second doping layer 400 is located on the second side surface 102 of the functional layer 100, the second side surface 220 of the absorption layer 200, and the surface of the absorption layer 200 away from the functional layer 100. Moreover, one end of the first doping layer 300 close to the second doping layer 400 and one end of the second doping layer 400 close to the first doping layer 300 have a preset distance L1 in the first direction; the doping types of the first doping layer 300 and the second doping layer 400 are different.

[0034] It is understandable that the first direction is the width direction of the functional layer 100. The absorption layer 200 is located on a partial surface of the functional layer 100. The first doping layer 300 and the second doping layer 400 are arranged oppositely along the first direction on both sides of the absorption layer 200. Specifically, the first side of the first doping layer 300 is located on the first side surface 101 of the functional layer 100, and the second side of the first doping layer 300 is located on the first side surface 210 of the absorption layer 200; the middle part of the second doping layer 400 is located on the second side surface 220 of the absorption layer 200, the first side of the second doping layer 400 is located on the second side surface 102 of the functional layer 100, and the second side of the second doping layer 400 is located on the surface of the absorption layer 200 away from the functional layer 100. It should be noted here that the surface area where the functional layer 100 contacts the absorption layer 200 is the middle surface. Along the first direction, the surface areas of the functional layer 100 on both sides of the middle surface are the first side surface 101 and the second side surface 102 respectively.

[0035] Specifically, the first doping layer 300 adopts an "L"-shaped doping structure formed on the first side surface 210 of the absorption layer 200 and the first side surface 101 of the functional layer 100. The second doping layer 400 adopts a "Z"-shaped doping structure formed on the second side surface 102 of the functional layer 100, the second side surface of the absorption layer 200, and the surface of the absorption layer 200 away from the functional layer 100. Thus, the detector P + and N + adopts the "L" and "Z"-shaped doping forms in the ohmic contact regions, which can form staggered but isolated fast carrier channels in space, effectively shorten the carrier transit time, and thereby improve the bandwidth of the detector. It should be noted that the detector in this embodiment is particularly suitable for wide rectangular waveguide or wide ridge waveguide detectors, and for infrared band detectors that require wide rectangular waveguide or wide ridge waveguide.

[0036] In the semiconductor photodetector provided by the embodiment of the present invention, the first doping layer 300 adopts an "L"-shaped doping structure formed on the first side surface 210 of the absorption layer 200 and the first side surface 101 of the functional layer 100, and the second doping layer 400 adopts a "Z"-shaped doping structure formed on the second side surface 102 of the functional layer 100, the second side surface of the absorption layer 200, and the surface of the absorption layer 200 away from the functional layer 100, to form P + and N + ohmic contact regions, so as to optimize the carrier transport path, effectively shorten the carrier transit time, and thus improve the working bandwidth of the device, and can be applicable to high-speed photodetection applications.

[0037] According to the embodiment of the present invention, the first doping layer 300 and the second doping layer 400 are two material dopings of the detector, and the doping types of the heavily doped regions constituting the detector are P-type and N-type.

[0038] Exemplarily, the heavily doped region of the detector is composed of a first doped layer 300 and a second doped layer 400, which are doped with P-type and N-type respectively (or vice versa). In specific implementation, there are two configuration modes for the heavily doped region of the detector: First, the first doped layer 300 is P-type and adopts an "L" shaped structure; the second doped layer 400 is N-type and adopts a "Z" shaped structure.

[0039] Second, the first doped layer 300 is N-type and adopts an "L" shaped structure, and the second doped layer 400 is P-type and adopts a "Z" shaped structure.

[0040] It should be noted that the "L" shaped structure can achieve high-efficiency lateral conduction, while the "Z" shaped structure can expand the longitudinal carrier collection range. The synergistic effect of the two significantly improves the response speed and photoelectric conversion efficiency of the detector. At the same time, the doping design covering the surface of the absorption layer 200 away from the functional layer 100 can effectively avoid the risk of electrical short circuit and ensure the stability of the device under high-speed working conditions.

[0041] In an embodiment of the present invention, as Figure 1 shown, the first doped layer 300 includes a first doped sub-region 310 and a second doped sub-region 320 connected to each other. The first doped sub-region 310 is located on the first side surface 101 of the functional layer 100, and the second doped sub-region 320 is located on the first side surface 210 of the absorption layer 200.

[0042] The second doped layer 400 includes a third doped sub-region 410, a fourth doped sub-region 420, and a fifth doped sub-region 430 connected in sequence; the third doped sub-region 410 is located on the second side surface 102 of the functional layer 100, the fourth doped sub-region 420 is located on the second side surface 220 of the absorption layer 200, and the fifth doped sub-region 430 is located on the surface of the absorption layer 200 away from the functional layer 100, that is, the fifth doped sub-region 430 is located on the upper surface 230 of the absorption layer.

[0043] Optionally, the second doped sub-region 320 and the fifth doped sub-region 430 have a preset distance L1 in the first direction, and the preset distance is greater than 50 nm.

[0044] It can be understood that the absorption layer 200 can be composed of GeSn or other semiconductor materials. The absorption layer 200 is also the active region for carrier collection; the first doped layer 300 forms the first doped region, and the second doped layer 400 forms the second doped region. Then, the doping on the upper surface of the active region in the second doped region is not connected to the first doped region and maintains a distance of more than 50 nm.

[0045] It should be noted that the maximum value of the preset distance L1 is determined according to the transmission wavelength and transmission mode.

[0046] In one embodiment of the present invention, the peak doping depth of the first doped sub-region 310 is greater than the peak doping depth of the second doped sub-region 320.

[0047] In one embodiment of the present invention, the peak doping depth of the third doped sub-region 410 is greater than the peak doping depth of the fourth doped sub-region 420, and the peak doping depth of the third doped sub-region 410 is greater than the peak doping depth of the fifth doped sub-region 430.

[0048] Optionally, the doping depth of the first doped sub-region 310 and the doping depth of the third doped sub-region 410 are substantially equal to form a good ohmic contact region. The peak doping depths of the second doped sub-region 320 and the fourth doped sub-region 420 are equal.

[0049] Furthermore, the peak doping depth of the fifth doped sub-region 430 is equal to the peak doping depth of the fourth doped sub-region 420.

[0050] Exemplarily, the peak doping depths of the second doped sub-region 320, the fourth doped sub-region 420, and the fifth doped sub-region 430 are 20 - 100 nm, and the doping concentration is 1×10 18 ~9×10 19 cm³.

[0051] The peak doping depths of the first doped sub-region 310 and the third doped sub-region 410 are less than 200 nm, and the doping concentration is 1×10 18 ~9×10 19 cm³.

[0052] In this embodiment, the doping depths of the second doped sub-region 320, the fourth doped sub-region 420, and the fifth doped sub-region 430 are less than 50 nm.

[0053] The doping depths of the first doped sub-region 310 and the third doped sub-region 410 are less than 150 nm, and the peak doping concentration is 1×10 19 ~1×10 20 cm 3 .

[0054] It should be noted that the peak doping depth is the vertical distance from the surface to the position where the doping concentration reaches the maximum value during the ion implantation or diffusion doping process; this depth is determined by process parameters such as implantation energy and annealing conditions, and is the extreme point of the doping distribution. The doping depth is the effective boundary of the doped region, that is, the position where the doping concentration drops to the substrate background concentration or a specific threshold; in an actual device, the doping depth determines the position of the PN junction or the thickness of the conductive region.

[0055] It should be noted that the peak doping concentration is the maximum value of the doping atom concentration distribution curve in the semiconductor material, that is, the highest doping concentration at a certain point in space. The doping concentration generally refers to the doping atom density at a certain point or in a certain area of the material.

[0056] It can be understood that both the first doping layer 300 and the second doping layer 400 form doping regions. The surface or side of the doping region has the highest ion concentration, and the ion concentration gradually decreases from the surface to the inside or from the side to the inside. For example, the ion concentration of the first doping sub-region 310 gradually decreases from the surface towards the side close to the functional layer 100; the ion concentration of the second doping sub-region 320 gradually decreases from the side towards the side close to the second doping layer 400.

[0057] In an embodiment of the present invention, the thickness of the absorption layer 200 is less than the width of the absorption layer 200.

[0058] It can be understood that during the preparation of the detector, the thickness of the absorption layer 200 should be less than its width to ensure that the detector has a low transmission loss within the working wavelength band.

[0059] Among them, the length direction of the absorption layer 200 is the direction of incident light transmission; the thickness direction of the absorption layer 200 is the direction perpendicular to the upper surface of the substrate, that is, Figure 1 the Y direction in Figure 1 ; the width direction of the absorption layer 200 is parallel to the upper surface of the substrate and perpendicular to the length direction (incident light transmission direction), that is, the first direction,

[0060] Specifically, an initial absorption layer is grown on the functional layer 100, and the initial absorption layer is etched to form the absorption layer 200, that is, the light absorption region, on the functional layer 100. The etching height and width of the initial absorption layer generally combine the refractive index of the material and the working wavelength to select single-mode transmission of the light field in the working wavelength band, so as to effectively limit the light field within a specific wavelength range, and further improve the performance and stability of the device.

[0061] It can be understood that the material for forming the light absorption region of the detector can be formed by the substrate 110 and the active material on the substrate 110, including but not limited to SOI, Si, Ge, GeSn, GePb, InP, GaAs, GaN, GaSb, GaSb, InGaAs, InAs / GaSb and InAS / GaSb / AlSb superlattice, GaN, Ga2O3 materials.

[0062] In a specific embodiment of the present invention, the functional layer 100 can take the following three forms.

[0063] The first one is, as Figure 2As shown, the functional layer 100 includes a substrate 110 and a buffer layer 120 disposed on the substrate 110.

[0064] Specifically, the absorption layer 200 is disposed in the middle region of the surface of the buffer layer 120 on the side facing away from the substrate 110, and the first side of the first doping layer 300 and the first side of the second doping layer 400 are located on the surface of the buffer layer 120.

[0065] It can be understood that the buffer layer 120 is grown on the surface of the substrate 110, an initial absorption layer is grown on the buffer layer 120, and the initial absorption layer is etched, so as to form the absorption layer 200 in the middle region of the buffer layer 120 along the first direction, and the first doping layer 300 and the second doping layer 400 are respectively formed on both sides of the absorption layer 200 along the first direction.

[0066] Both the buffer layer 120 and the absorption layer 200 serve as active regions. The buffer layer 120 serves as active region 1, and the absorption layer 200 serves as active region 2. Active region 2 is located on the middle surface of active region 1. The ion implantation method is used to inject ion heavy doping regions on the upper surface of one side of active region 1 and on one side surface of active region 2 to form the first doping layer 300, that is, an "L"-shaped doping structure. The ion implantation method is used to inject ion heavy doping regions on the upper surface of the other side of active region 1, on the other side surface of active region 2, and on the upper surface of active region 2 to form the second doping layer 400, that is, a "Z"-shaped doping structure. It should be noted that when injecting ion heavy doping regions on the upper surface of active region 2, the upper surface of active region 2 cannot be completely covered, and it should not be connected to the first doping layer 300, and a spacing of more than 50 nm should be maintained.

[0067] Second, as Figure 3 shown, the functional layer 100 includes a substrate 110 and a buffer layer 120 disposed in the middle region of the substrate 110.

[0068] Specifically, the absorption layer 200 is disposed on the surface of the buffer layer 120 facing away from the substrate 110, and the first side of the first doping layer 300 and the first side of the second doping layer 400 are both located on the side surface of the buffer layer 120 and the surface of the substrate 110.

[0069] It can be understood that an initial buffer layer is grown on the surface of the substrate 110, the initial buffer layer is etched, so as to form the buffer layer 120 in the middle region of the substrate 110 along the first direction, and then the absorption layer 200 is grown on the buffer layer 120, and the first doping layer 300 and the second doping layer 400 are respectively formed on both sides of the absorption layer 200 along the first direction.

[0070] Both the buffer layer 120 and the absorption layer 200 serve as active regions. By means of ion implantation, ion heavy doping region implantation is carried out on one upper surface side of the substrate 110 and one side surface of the active region to form a first doping layer 300, that is, an "L"-shaped doping structure; by means of ion implantation, ion heavy doping region implantation is carried out on the other upper surface side of the substrate 110, the other side surface of the active region, and the upper surface of the active region to form a second doping layer 400, that is, a "Z"-shaped doping structure.

[0071] Thirdly, as Figure 4 shown, the functional layer 100 includes the substrate 110.

[0072] Specifically, the absorption layer 200 is disposed in the middle region of the substrate 110, and the first side of the first doping layer 300 and the first side of the second doping layer 400 are located on the surface of the substrate 110.

[0073] It can be understood that an initial absorption layer is grown on the surface of the substrate 110, and the initial absorption layer is etched, so as to form the absorption layer 200 in the middle region of the substrate 110 along the first direction, and the first doping layer 300 and the second doping layer 400 are respectively formed on both sides of the absorption layer 200 along the first direction.

[0074] The absorption layer 200 serves as an active region. By means of ion implantation, ion heavy doping region implantation is carried out on one upper surface side of the substrate 110 and one side surface of the active region to form a first doping layer 300, that is, an "L"-shaped doping structure; by means of ion implantation, ion heavy doping region implantation is carried out on the other upper surface side of the substrate 110, the other side surface of the active region, and the upper surface of the active region to form a second doping layer 400, that is, a "Z"-shaped doping structure.

[0075] It should be noted that the first doping layer 300 includes a connected first doping sub-region 310 and a second doping sub-region 320, and the second doping layer 400 includes a third doping sub-region 410, a fourth doping sub-region 420, and a fifth doping sub-region 430 that are connected in sequence; wherein, the first doping sub-region 310 and the third doping sub-region 410 are formed on the surface of the active region or the substrate, and the first doping sub-region 310 and the third doping sub-region 410 can also be formed by means of in-situ doping.

[0076] In a specific embodiment of the present invention, the buffer layer 120 and the absorption layer 200 are formed by homoepitaxy or heteroepitaxy on the substrate 110, and by hetero-bonding on the substrate 110.

[0077] Optionally, substrates 110 of different types of semiconductors include InP, Si, Ge, SOI, GaAS, GaN, GaSb. The material of the absorption layer 200 can be formed by the substrate, or by epitaxial materials and hetero-bonding. The materials for epitaxy and hetero-bonding include but are not limited to Si, Ge, GeSn, GePb, InP, GaAS, GaN, GaSb, GaSb, InGaAs, InAs / GaSb and InAS / GaSb / AlSb superlattice, GaN, Ga2O3 materials.

[0078] In an embodiment of the present invention, as Figure 1 shown, the detector further includes counter electrodes, namely the first electrode 510 and the second electrode 520 respectively. The first electrode 510 is located on the first side of the first doping layer 300, and the second electrode 520 is located on the first side of the second doping layer 400. The first electrode 510 and the second electrode 520 are used to access electrical excitation. Specifically, by disposing the first electrode 510 and the second electrode 520 on both sides of the absorption layer 200, the carrier transport speed can be increased, which is a good choice for fabricating high-speed devices.

[0079] It should be noted that the first electrode 510 and the second electrode 520 can also be located on the substrate 110 on both sides of the absorption layer 200.

[0080] Furthermore, an insulating material such as silicon oxide or silicon nitride is grown on the surfaces of the first doping layer 300 and the second doping layer 400 away from the functional layer 100, so as to form a passivation layer 600 on the first doping layer 300 and the second doping layer 400, and openings are made on the passivation layer 600 for the first electrode 510 and the second electrode 520 to expose the ohmic contact regions of the electrodes.

[0081] Based on the semiconductor photodetector provided in any of the above embodiments, an embodiment of the present invention proposes a method for fabricating a semiconductor photodetector, as Figure 5 shown, the fabrication method includes the following steps: Step 10: Form an absorption layer 200 on a partial surface of the functional layer 100.

[0082] Step 20: Form a first doping layer 300 on the first side surface 210 of the absorption layer 200 and the first side surface 101 of the functional layer 100.

[0083] Step 30: Form a second doping layer 400 on the second side surface 102 of the functional layer 100, the second side surface 220 of the absorption layer 200, and the surface of the absorption layer 200 away from the functional layer 100.

[0084] Among them, one end of the first doping layer 300 close to the second doping layer 400 has a preset distance from one end of the second doping layer 400 close to the first doping layer 300 along the first direction; the doping types of the first doping layer 300 and the second doping layer 400 are different.

[0085] It can be understood that the first doping layer 300 adopts an "L"-shaped doping structure formed on the first side surface 210 of the absorption layer 200 and the first side surface 101 of the functional layer 100, and the second doping layer 400 adopts a "Z"-shaped doping structure formed on the second side surface 102 of the functional layer 100, the second side surface of the absorption layer 200, and the surface of the absorption layer 200 far from the functional layer 100. In this way, for the detector P + and N + the ohmic contact regions adopt "L" and "Z"-shaped doping forms, which can form staggered but isolated carrier fast channels in space, effectively shorten the carrier transit time, and thus improve the bandwidth of the detector. It should be noted that the detector in this embodiment has the advantages of large bandwidth and high responsivity, and is particularly suitable for wide rectangular waveguide or wide ridge waveguide detectors, as well as infrared band detectors that require wide rectangular waveguides or wide ridge waveguides.

[0086] It should be noted that the structural types of the detectors in this embodiment may include evanescent wave coupling detectors and direct coupling type detectors.

[0087] In a specific embodiment of the present invention, as Figure 1 shown, when the functional layer 100 includes a substrate 110 and a buffer layer 120 disposed on the substrate 110, the manufacturing method of the semiconductor photodetector includes the following steps: S1. Grow a buffer layer 120 on the surface of the substrate 110.

[0088] S2. Grow an initial absorption layer on the buffer layer 120 and etch it.

[0089] It can be understood that by growing an initial absorption layer on the buffer layer 120 and etching the initial absorption layer, the etching height and width are combined with the refractive index of the material and the working wavelength to select the single-mode transmission of the optical field in the working band, so as to form a ridge-shaped absorption layer 200 in the middle region of the buffer layer 120 along the first direction.

[0090] S3. Form the first doping layer 300.

[0091] It can be understood that both the buffer layer 120 and the absorption layer 200 serve as active regions. The buffer layer 120 serves as active region 1, and the absorption layer 200 serves as active region 2. Active region 2 is located on the middle surface of active region 1. Ion implantation is used to perform ion heavy doping region implantation on one upper surface of active region 1 and one side surface of active region 2 to form the first doping layer 300, that is, an "L"-shaped doping structure.

[0092] S4. Form the second doping layer 400.

[0093] It can be understood that ion implantation is used to perform ion heavy doping region implantation on the other upper surface of active region 1, the other side surface of active region 2, and the upper surface of active region 2 to form the second doping layer 400, that is, a "Z"-shaped doping structure. It should be noted that when performing ion heavy doping region implantation on the upper surface of active region 2, it should not be connected to the first doping layer 300 and maintain a spacing of more than 50 nm.

[0094] S5. Form the passivation layer 600.

[0095] It can be understood that insulating materials such as silicon oxide or silicon nitride are grown on the surfaces of the first doping layer 300 and the second doping layer 400 away from the functional layer 100, and openings are made for the first electrode 510 and the second electrode 520, so as to form the passivation layer 600 on the first doping layer 300 and the second doping layer 400.

[0096] In this embodiment, the first doping layer 300 and the second doping layer 400 are formed by ion implantation, and the ion implantation region is located outside the optical field distribution. Among them, the doping depth of the upper surface and the side surface of active region 2 is less than 50 nm; the doping depth of the upper surface of active region 1 is less than 150 nm, and the doping peak concentration is 1×10 19 ~1×10 20 cm 3 .

[0097] As Figure 6 shown, the present invention compares the bandwidth performance of a conventional doped Si waveguide evanescent wave coupled Ge photodetector with a photodetector using an "L"-shaped and a "Z"-shaped doping structure at -1V voltage; Figure 6 In Figure 6The curve a represents a conventionally doped photodetector, and the curve b represents the "L"-shaped and "Z"-shaped doped photodetectors of this embodiment. It can be seen that the bandwidth of the photodetector with the "L"-shaped and "Z"-shaped doping structures in this embodiment reaches 50 GHz, while the bandwidth of the detector with the conventional structure is only 27 GHz. Thus, it can be seen that the doping structure proposed by the present invention can significantly improve the working bandwidth of the photodetector, which is more conducive to applications in high-speed optical communication systems.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A semiconductor photodetector, characterized in that, Comprising: Functional layer; Absorbing layer, located on a partial surface of the functional layer, the absorbing layer having a first side and a second side opposite to each other in a first direction; First doping layer, a first side of the first doping layer being located on a first side surface of the functional layer, a second side of the first doping layer being located on the first side of the absorbing layer; Second doping layer, a middle part of the second doping layer being located on the second side of the absorbing layer, a first side of the second doping layer being located on a second side surface of the functional layer, a second side of the second doping layer being located on a surface of the absorbing layer away from the functional layer; a preset distance exists between one end of the first doping layer close to the second doping layer and one end of the second doping layer close to the first doping layer in the first direction; the doping types of the first doping layer and the second doping layer are different.

2. The semiconductor photodetector according to claim 1, wherein, The first doping layer includes a connected first doping sub-region and second doping sub-region, the first doping sub-region being located on the first side surface of the functional layer, the second doping sub-region being located on the first side of the absorbing layer, and a peak doping depth of the first doping sub-region being greater than a peak doping depth of the second doping sub-region.

3. The semiconductor photodetector according to claim 2, characterized in that, The peak doping depth of the first doped sub-region is less than 200 nm, and / or the doping concentration of the first doped sub-region is 1×10 18 ~9×10 19 cm³; And / or, The peak doping depth of the second doped sub-region is 20 to 100 nm, and / or the doping concentration of the second doped sub-region is 1×10 18 ~9×10 19 cm³.

4. The semiconductor optoelectronic detector according to claim 2, characterized in that, The second doping layer includes a third doping sub-region, a fourth doping sub-region, and a fifth doping sub-region connected in sequence; The third doping sub-region is located on the second side surface of the functional layer, the fourth doping sub-region is located on the second side of the absorbing layer, the fifth doping sub-region is located on the surface of the absorbing layer away from the functional layer, a peak doping depth of the third doping sub-region is greater than a peak doping depth of the fourth doping sub-region, and a peak doping depth of the third doping sub-region is greater than a peak doping depth of the fifth doping sub-region.

5. The semiconductor photodetector according to claim 4, wherein The peak doping depths of the second doping sub-region and the fourth doping sub-region are equal.

6. The semiconductor photodetector according to claim 1, wherein The thickness of the absorbing layer is less than the width of the absorbing layer, and / or, The preset distance is greater than 50 nm.

7. The semiconductor photodetector according to any one of claims 1 to 6, characterized in that, The functional layer includes: Substrate; Buffer layer, disposed on the substrate; The absorbing layer is disposed in a middle region of a surface of the buffer layer facing away from the substrate, and a first side of the first doping layer and a first side of the second doping layer are located on the surface of the buffer layer.

8. The semiconductor photodetector according to any one of claims 1 to 6, characterized in that, The functional layer includes: Substrate; Buffer layer, disposed in a middle region of the substrate; The absorbing layer is disposed on a surface of the buffer layer facing away from the substrate, and a first side of the first doping layer and a first side of the second doping layer are both located on a side surface of the buffer layer and a surface of the substrate.

9. The semiconductor photodetector according to any one of claims 1 to 6, characterized in that, The functional layer includes a substrate, the absorbing layer is disposed in a middle region of the substrate, and a first side of the first doping layer and a first side of the second doping layer are located on the surface of the substrate.

10. A method for preparing a semiconductor photodetector, characterized in that, Comprising: Forming an absorbing layer on a partial surface of the functional layer; Forming a first doping layer on the first side of the absorbing layer and a first side surface of the functional layer; A second doped layer is formed on the second side surface of the functional layer, the second side surface of the absorption layer, and the surface of the absorption layer away from the functional layer; one end of the first doped layer close to the second doped layer has a preset distance from one end of the second doped layer close to the first doped layer in a first direction; the doping types of the first doped layer and the second doped layer are different.

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