Monolithically integrated resonant cavity enhanced waveguide photodetector

Abstract

The application relates to the field of photoelectric technology and provides a monolithic integrated resonant cavity enhanced waveguide photodetector which comprises a semi-insulating substrate, a waveguide photodetector epitaxial layer, an N metal electrode and a P metal electrode; the waveguide photodetector epitaxial layer comprises a waveguide layer and a photodetector epitaxial layer; the semi-insulating substrate, the waveguide layer, the photodetector epitaxial layer and the P metal electrode are sequentially arranged along the Z-axis direction; the N metal electrode is connected with the waveguide layer; the waveguide photodetector epitaxial layer has a first end and a second end which are opposite to each other along the X-axis direction; the photodetector epitaxial layer is provided with a first groove; the waveguide photodetector epitaxial layer is provided with a second groove; the first groove is arranged close to the first end; the second groove is arranged close to the second end; and the first groove and the second groove are arranged along the Y-axis direction; the first groove and the second groove are arranged to form a resonant cavity composed of a distributed Bragg reflector, so that good responsivity and relatively fast response speed can be simultaneously satisfied.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic technology, and in particular to a monolithically integrated resonant cavity enhanced waveguide photodetector. Background Technology

[0002] Optical detectors are used to convert optical signals into electrical signals and have wide applications in high-speed, high-power optical fiber communication systems, wireless optical fiber communication systems, and terahertz wave sources. Performance metrics for optical detectors include responsivity and response speed.

[0003] Waveguide photodetectors are a type of photodetector. In order to absorb as much incident light as possible, i.e. to ensure responsivity, the active area of ​​the waveguide photodetector needs to be large. However, the active area is inversely proportional to the response speed. That is, a larger active area will lead to a decrease in response speed, making it difficult for waveguide photodetectors to simultaneously meet the requirements of good responsivity and fast response speed. Summary of the Invention

[0004] This invention provides a monolithically integrated resonant cavity enhanced waveguide photodetector to solve or improve the problem that existing waveguide photodetectors cannot simultaneously satisfy good responsivity and fast response speed.

[0005] This invention provides a monolithically integrated resonant cavity enhanced waveguide photodetector, comprising: a semi-insulating substrate, a waveguide photodetector epitaxial layer, an N-metal electrode, and a P-metal electrode; the waveguide photodetector epitaxial layer includes a waveguide layer and a photodetector epitaxial layer, the semi-insulating substrate, the waveguide layer, the photodetector epitaxial layer, and the P-metal electrode are arranged sequentially along the Z-axis direction, and the N-metal electrode is connected to the waveguide layer; the waveguide photodetector epitaxial layer has a first end and a second end opposite to each other along the X-axis direction, the photodetector epitaxial layer has a first groove, and the waveguide photodetector epitaxial layer has a second groove, the first groove being disposed near the first end, and the second groove being disposed near the second end, both the first groove and the second groove being arranged along the Y-axis direction.

[0006] According to the present invention, a monolithically integrated resonant cavity enhanced waveguide photodetector is provided, wherein the first groove extends from the middle of the epitaxial layer of the photodetector along the Y-axis toward both ends of the epitaxial layer of the photodetector; and the second groove extends from the middle of the epitaxial layer of the waveguide photodetector along the Y-axis toward both ends of the epitaxial layer of the photodetector.

[0007] According to the present invention, a monolithically integrated resonant cavity enhanced waveguide photodetector is provided, wherein the first groove extends from the middle of the epitaxial layer of the photodetector along the Y-axis towards both ends by a distance equal to L1 / 2; the second groove extends from the middle of the epitaxial layer of the waveguide photodetector along the Y-axis towards both ends by a distance equal to L1 / 2; wherein L1 is the width of the epitaxial layer of the photodetector along the Y-axis.

[0008] According to the present invention, a monolithically integrated resonant cavity enhanced waveguide photodetector is provided, wherein the first groove extends from the middle of the epitaxial layer of the photodetector along the Y-axis towards both ends by a distance less than L1 / 2; the second groove extends from the middle of the epitaxial layer of the waveguide photodetector along the Y-axis towards both ends by a distance less than L1 / 2; wherein L1 is the width of the epitaxial layer of the photodetector along the Y-axis.

[0009] According to the present invention, a monolithically integrated resonant cavity enhanced waveguide photodetector is provided, wherein the first groove includes a first groove body and a second groove body, the first groove body and the second groove body being collinear; the second groove includes a third groove body and a fourth groove body, the third groove body and the fourth groove body being collinear; the first groove body and the second groove body extend from the edge of the photodetector epitaxial layer along the Y-axis direction toward the center of the photodetector epitaxial layer, the third groove body and the fourth groove body extend from the edge of the photodetector epitaxial layer along the Y-axis direction toward the center of the waveguide photodetector epitaxial layer; the first groove body and the second groove body form a first gap along the Y-axis direction; the third groove body and the fourth groove body form a second gap along the Y-axis direction.

[0010] According to the present invention, a monolithically integrated resonant cavity enhanced waveguide photodetector is provided, wherein a plurality of second grooves are provided, and the plurality of second grooves are spaced apart along the X-axis direction.

[0011] According to the present invention, a monolithically integrated resonant cavity enhanced waveguide photodetector is provided, wherein the spacing between two adjacent second grooves is [missing information]. Where K is a positive odd number, λ is the wavelength of the incident light, and n1 is the refractive index of the waveguide layer.

[0012] According to the present invention, in a monolithically integrated resonant cavity enhanced waveguide photodetector, the widths of the first groove and the second groove along the X-axis direction are equal. Where N is a positive odd number, λ is the wavelength of the incident light, and n2 is the refractive index of the medium in the first groove and the second groove.

[0013] According to the present invention, a monolithically integrated resonant cavity enhanced waveguide photodetector is provided, wherein the epitaxial layer of the photodetector includes a collecting layer, a cliff layer, a spacer layer, an absorption layer, an electron blocking layer, and a P-contact layer; the collecting layer, the cliff layer, the spacer layer, the absorption layer, the electron blocking layer, and the P-contact layer are arranged sequentially along the Z-axis direction, the collecting layer is connected to the waveguide layer, and the P-contact layer is connected to the P-metal electrode.

[0014] According to the present invention, in a monolithically integrated resonant cavity enhanced waveguide photodetector, the first groove and the second groove have a square cross-sectional shape on a plane perpendicular to the Y-axis.

[0015] The monolithically integrated resonant cavity enhanced waveguide photodetector provided by this invention involves etching a first groove on the epitaxial layer of the photodetector and a second groove on the epitaxial layer of the waveguide photodetector, and filling the first and second grooves with a dielectric material. This dielectric material, in turn, periodically alternates with the semiconductor material to form two pairs of distributed Bragg mirrors with different period numbers and etching depths. The waveguide (DBR) is a resonant cavity formed between two pairs of DBRs. Incident light enters the waveguide layer from the X-axis and is confined within the waveguide layer for propagation. When it reaches the epitaxial layer of the photodetector, the incident light couples and continues to propagate along the X-axis. The epitaxial layer of the photodetector absorbs the incident light to generate photogenerated carriers. The unabsorbed incident light propagates back and forth within the resonant cavity, thereby increasing the effective light absorption length of the photodetector. This is equivalent to increasing the responsivity of the photodetector within a smaller absorption length. Correspondingly, there is no need to set a large active area, thereby reducing the RC time constant and improving the response speed of the photodetector. Compared with the conventional waveguide photodetector with the same structure, the structure of this invention can simultaneously meet high responsivity and response speed with a smaller active area and a smaller absorption layer thickness, thereby achieving a high bandwidth efficiency product. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is one of the structural schematic diagrams of the monolithically integrated resonant cavity enhanced waveguide optical detector provided by the present invention;

[0018] Figure 2 This is a cross-sectional schematic diagram of the monolithically integrated resonant cavity enhanced waveguide optical detector provided by the present invention;

[0019] Figure 3 This is the second schematic diagram of the monolithically integrated resonant cavity enhanced waveguide photodetector provided by the present invention (excluding the P metal electrode);

[0020] Figure 4 This is the third schematic diagram of the monolithically integrated resonant cavity enhanced waveguide photodetector provided by the present invention (excluding the P metal electrode);

[0021] Figure 5 This is the fourth schematic diagram of the monolithically integrated resonant cavity enhanced waveguide photodetector provided by the present invention (excluding the P metal electrode);

[0022] Figure 6 This is the fifth schematic diagram of the monolithically integrated resonant cavity enhanced waveguide photodetector provided by the present invention (excluding the P metal electrode);

[0023] Figure 7 This is the sixth schematic diagram of the structure of the monolithically integrated resonant cavity enhanced waveguide photodetector provided by the present invention.

[0024] Figure label:

[0025] 1: Semi-insulating substrate; 2: Waveguide photodetector epitaxial layer; 21: Waveguide layer; 22: Photodetector epitaxial layer; 221: Collection layer; 222: Cliff layer; 223: Spacer layer; 224: Absorption layer; 225: Electron blocking layer; 226: P contact layer; 3: N metal electrode; 4: P metal electrode; 5: First groove; 51: First trench; 52: Second trench; 6: Second groove; 61: Third trench; 62: Fourth trench. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not 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 explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0029] The following is combined with Figures 1 to 7 This invention describes a monolithically integrated resonant cavity enhanced waveguide optical detector; it should be noted that, for ease of description, the monolithically integrated resonant cavity enhanced waveguide optical detector is simply referred to as an optical detector.

[0030] like Figures 1 to 7 As shown in the figure, the monolithically integrated resonant cavity enhanced waveguide photodetector shown in this embodiment includes: a semi-insulating substrate 1, a waveguide photodetector epitaxial layer 2, an N metal electrode 3, and a P metal electrode 4.

[0031] The waveguide photodetector epitaxial layer 2 includes a waveguide layer 21 and a photodetector epitaxial layer 22. A semi-insulating substrate 1, waveguide layer 21, photodetector epitaxial layer 22, and P-metal electrode 4 are arranged sequentially along the Z-axis. The semi-insulating substrate 1 is connected to the waveguide layer 21, the waveguide layer 21 is connected to the photodetector epitaxial layer 22, the photodetector epitaxial layer 22 is connected to the P-metal electrode 4, and the N-metal electrode 3 is connected to the waveguide layer 21. The waveguide photodetector epitaxial layer has a first end and a second end that are opposite to each other along the X-axis. The photodetector epitaxial layer 22 has a first groove 5 that penetrates the entire photodetector epitaxial layer 22 along the Z-axis. The waveguide photodetector epitaxial layer 22 also has a second groove 6 that extends along the Z-axis. The Z-axis direction penetrates the entire waveguide photodetector epitaxial layer 2, which includes two parts: waveguide layer 21 and photodetector epitaxial layer 22. It can be understood that the second groove 6 penetrates both waveguide layer 21 and photodetector epitaxial layer 22. Correspondingly, the depth of the second groove 6 is greater than the depth of the first groove 5. The first groove 5 is located near the first end, and the second groove 6 is located near the second end. Both the first groove 5 and the second groove 6 are arranged along the Y-axis direction. The X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other. The first groove 5 and the second groove 6 are filled with the same medium, which can be air or a filling material, including benzocyclobutene or Si3N4.

[0032] Specifically, the monolithically integrated resonant cavity enhanced waveguide photodetector shown in this embodiment etches a first groove 5 on the epitaxial layer 22 of the photodetector and a second groove 6 on the epitaxial layer 2 of the waveguide photodetector. The first groove 5 and the second groove 6 are filled with a dielectric material, thereby periodically alternating with the semiconductor material to form two pairs of distributed Bragg mirrors with different period numbers and different etching depths. The two pairs of DBRs form a resonant cavity. The incident light enters the waveguide layer 21 from the X-axis and is confined within the waveguide layer 21 for propagation. When it reaches the epitaxial layer 22 of the photodetector, the incident light couples and continues to propagate along the X-axis. The epitaxial layer 22 of the photodetector absorbs the incident light to generate photogenerated carriers. The unabsorbed incident light propagates back and forth in the resonant cavity, thereby increasing the effective light absorption length of the photodetector. This is equivalent to increasing the responsivity of the photodetector within a smaller absorption length. Correspondingly, there is no need to set a large active area, thereby reducing the RC time constant and improving the response speed of the photodetector. Compared with the conventional waveguide photodetector with the same structure, the structure shown in this embodiment can simultaneously meet the requirements of high responsivity and response speed with a smaller active area and a smaller absorption layer thickness, thereby achieving a high bandwidth efficiency product.

[0033] It should be noted that the etching depth of the first groove 5 is the entire epitaxial layer 22 of the photodetector, and the etching depth is the thickness of the epitaxial layer 22 of the photodetector in the Z-axis direction. Correspondingly, the etching cutoff position is located above the waveguide layer 21, thereby ensuring that the incident light is coupled as much as possible from the waveguide layer 21 and enters the photodetector. The etching depth of the second groove 6 is the entire epitaxial layer 2 of the waveguide photodetector, and the etching depth is the thickness of the epitaxial layer 2 of the waveguide photodetector in the Z-axis direction. Correspondingly, the etching cutoff position is located above the semi-insulating substrate 1, thereby ensuring that the incident light that has not coupled into the photodetector in the waveguide layer 21 is reflected and then coupled into the photodetector again. The cross-sectional shape of the first groove 5 and the second groove 6 in the plane perpendicular to the Y-axis direction is square, that is, the first groove 5 and the second groove 6 are square grooves.

[0034] It should also be noted that the X-axis direction is... Figure 2 , Figure 4 and Figure 6 The direction from left to right or from right to left, the Y-axis direction is Figure 4 and Figure 6 The direction from top to bottom or bottom to top, the Y-axis direction is also... Figure 7 The direction from left to right or from right to left, the Z-axis direction is Figure 2 and Figure 7 The directions from top to bottom or bottom to top are defined as follows: the X-axis is the direction of the X-axis in the spatial rectangular coordinate system, the Y-axis is the direction of the Y-axis, and the Z-axis is the direction of the Z-axis.

[0035] In this design, a semi-insulating substrate 1 serves as the base on which the waveguide photodetector epitaxial layer 2 is heteroepitaxially grown. The waveguide layer 21 guides the transmission of incident light and couples it into the photodetector, while also forming a good ohmic contact with the N metal electrode 3. The waveguide layer 21 is made of InGaAsP, with a thickness between 0.5 and 2 μm, and is a donor-type doped layer with a doping concentration of 1 × 10⁻⁶. 18 -1×10 19 cm -3 between

[0036] The following is combined Figures 1 to 6 The three structural forms of the first groove 5 and the second groove 6 are described.

[0037] like Figures 1 to 4As shown, the first groove 5 extends from the middle of the photodetector epitaxial layer 22 along the Y-axis towards both ends of the photodetector epitaxial layer 22; the second groove 6 extends from the middle of the waveguide photodetector epitaxial layer 2 along the Y-axis towards both ends of the photodetector epitaxial layer 22; wherein, the width of the photodetector epitaxial layer 22 along the Y-axis is L1, and since the waveguide layer 21 needs to be connected to the N metal electrode, the width of the waveguide layer 21 along the Y-axis is greater than L1, and the middle of the waveguide layer 21 along the Y-axis coincides with the middle of the photodetector epitaxial layer 22 along the Y-axis, that is, the middle of the photodetector epitaxial layer 22 along the Y-axis coincides with the middle of the waveguide photodetector epitaxial layer 2 along the Y-axis.

[0038] Specifically, the first structural form is similar to the second structural form, with both the first groove 5 and the second groove 6 extending from the middle along the Y-axis to both ends.

[0039] like Figure 1 and Figure 2 As shown, for the first structural form, the first groove 5 extends from the middle of the photodetector epitaxial layer 22 along the Y-axis towards both ends by a distance equal to L1 / 2; the second groove 6 extends from the middle of the waveguide photodetector epitaxial layer 2 along the Y-axis towards both ends by a distance equal to L1 / 2.

[0040] Specifically, for the first structural form, the first groove 5 and the second groove 6 completely cut off the photodetector epitaxial layer 22 along the Y-axis. Furthermore, since the second groove 6 is deeper, a groove of length L1 is also formed on the waveguide layer 21 directly below the photodetector epitaxial layer 22. In order to facilitate the connection between the P metal electrode 4 and the photodetector epitaxial layer 22, a filler material needs to be filled in the first groove 5 and the second groove 6. That is, the medium in the first groove 5 and the second groove 6 is the filler material, and the filler material can support the P metal electrode 4.

[0041] like Figure 3 and Figure 4 As shown, for the second structural form, the first groove 5 extends from the middle of the photodetector epitaxial layer 22 along the Y-axis towards both ends by a distance less than L1 / 2; the second groove 6 extends from the middle of the waveguide photodetector epitaxial layer 2 along the Y-axis towards both ends by a distance less than L1 / 2.

[0042] Specifically, for the second structural form, the first groove 5 is located inside the photodetector epitaxial layer 22, that is, the photodetector epitaxial layer 22 is partially cut off, and a gap L2 is left between the two ends of the first groove 5 along the Y-axis and the edge of the photodetector epitaxial layer 22; the second groove 6 is located inside the waveguide photodetector epitaxial layer 2, that is, the waveguide photodetector epitaxial layer 2 is partially cut off, and a gap L2 is left between the two ends of the second groove 6 along the Y-axis and the edge of the photodetector epitaxial layer 22; the reserved gap L2 can support the P metal electrode 4. At this time, the first groove 5 and the second groove 6 can be filled with either air or filler material.

[0043] like Figure 5 and Figure 6 As shown, for the third structural form, the first groove 5 includes a first groove 51 and a second groove 52, which are collinear; the second groove 6 includes a third groove 61 and a fourth groove 62, which are collinear; the first groove 51 and the second groove 52 extend from the edge of the photodetector epitaxial layer 22 along the Y-axis toward the center of the photodetector epitaxial layer 22, and the third groove 61 and the fourth groove 62 extend from the edge of the photodetector epitaxial layer 22 along the Y-axis toward the center of the waveguide photodetector epitaxial layer 2; the first groove 51 and the second groove 52 form a first gap L3 along the Y-axis, and the third groove 61 and the fourth groove 62 form a second gap L4 along the Y-axis.

[0044] Specifically, for the third structural form, the first groove 51 and the second groove 52 extend towards the center of the photodetector epitaxial layer 22 from both sides along the Y-axis direction, and a first gap L3 is reserved, that is, the sum of the lengths of the first groove 51 and the second groove 52 is less than the width L1 of the photodetector epitaxial layer 22, and the first groove 51 and the second groove 52 together form the first groove 5; the third groove 61 and the fourth groove 62 extend towards the center of the waveguide photodetector epitaxial layer 22 from both sides along the Y-axis direction. The middle sections extend towards each other and are reserved with a second gap L4. That is, the sum of the lengths of the third groove 61 and the fourth groove 62 is less than the width L1 of the waveguide photodetector epitaxial layer 22. The third groove 61 and the fourth groove 62 together form the second groove. Correspondingly, the first groove 5 partially cuts off the photodetector epitaxial layer 22, and the second groove 6 partially cuts off the waveguide photodetector epitaxial layer 2. The first gap L3 and the second gap L4 can support the P metal electrode 4. At this time, the first groove 5 and the second groove 6 can be filled with either air or filler material.

[0045] L3 and L4 can be equal.

[0046] In some embodiments, such as Figures 1 to 6As shown in the figure, the second groove 6 shown in this embodiment is provided in multiple ways, and the multiple second grooves 6 are spaced apart along the X direction.

[0047] Specifically, by setting multiple second grooves 6 at intervals, the reflectivity of uncoupled incident light is correspondingly improved.

[0048] In some embodiments, such as Figure 2 As shown, in this embodiment, the distance L5 between two adjacent second grooves 6 satisfies the following formula:

[0049]

[0050] Where K is a positive odd number, which can be 1, 3, 5, 7, 9, etc.; λ is the wavelength of the incident light; and n1 is the refractive index of waveguide layer 21.

[0051] In some embodiments, such as Figure 2 As shown in the figure, the widths of the first groove 5 and the second groove 6 along the X-axis are equal in this embodiment, that is, the etching widths L6 are equal, and L6 satisfies the following formula:

[0052]

[0053] Where N is a positive odd number, which can be 1, 3, 5, 7, 9, etc.; λ is the wavelength of the incident light; and n2 is the refractive index of the medium in the first groove 5 and the second groove 6.

[0054] In some embodiments, such as Figure 7 As shown, the photodetector epitaxial layer 22 in this embodiment includes a collection layer 221, a cliff layer 222, a spacer layer 223, an absorption layer 224, an electron blocking layer 225, and a P-contact layer 226. The collection layer 221, cliff layer 222, spacer layer 223, absorption layer 224, electron blocking layer 225, and P-contact layer 226 are arranged sequentially along the Z-axis. The collection layer 221 is connected to the waveguide layer 21, and the P-contact layer 226 is connected to the P-metal electrode 4.

[0055] Among them, the collecting layer 221 is used for electron transport and regulating junction capacitance; the cliff layer 222 is used to reduce conduction band discontinuity between heterojunctions; the spacer layer 223 is used to reduce conduction band discontinuity between heterojunctions; the absorption layer 224 is used for photoelectric conversion to generate photogenerated carriers; the electron blocking layer 225 is used to block electron diffusion to the P contact layer 226; and the P contact layer 226 is used to form a good ohmic contact with the P metal electrode 4.

[0056] The material of the collection layer 221 is InGaAsP or InP, with a thickness between 0.3 and 0.5 μm. The doping type is donor type, and the doping concentration is 1 × 10⁻⁶ from the end near the waveguide layer 21. 18 cm -3The linear gradient gradually decreases to 1×10 near the 222nd cliff layer. 15 cm -3 The material of cliff layer 222 is InGaAsP, with a thickness between 0.005 and 0.02 μm, and it is a donor-type doped layer with a doping concentration of 1 × 10⁻⁶. 18 -5×10 18 cm -3 Between; the spacer layer 223 is made of InGaAsP, with a thickness between 0.005 and 0.02 μm, and is a donor-type doped layer with a doping concentration of 1 × 10⁻⁶. 15 cm -3 The absorber layer 224 is made of InGaAs, with a thickness between 0.2 and 0.4 μm. It is an acceptor-type doped layer, with a doping concentration of 1 × 10⁻⁶ from the end near the spacer layer 223. 15 cm -3 The linear gradient gradually decreases to 5 × 10 near the electron blocking layer 225. 18 cm -3 The electron blocking layer 225 is made of InGaAsP, with a thickness between 0.02 and 0.05 μm, and is an acceptor-type doped layer with a doping concentration of 1 × 10⁻⁶. 18 -1×10 19 cm -3 The P-contact layer 226 is made of InGaAs with a thickness between 0.02 and 0.05 μm, and is an acceptor-type doped layer with a doping concentration of 5 × 10⁻⁶. 18 -2×10 19 cm -3 .

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions 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 monolithically integrated resonant cavity enhanced waveguide photodetector, characterized in that, include: Semi-insulating substrate, waveguide photodetector epitaxial layer, N-metal electrode and P-metal electrode; The waveguide photodetector epitaxial layer includes a waveguide layer and a photodetector epitaxial layer. The semi-insulating substrate, the waveguide layer, the photodetector epitaxial layer and the P metal electrode are arranged sequentially along the Z-axis direction, and the N metal electrode is connected to the waveguide layer. The waveguide photodetector epitaxial layer has a first end and a second end that are opposite to each other along the X-axis direction. The photodetector epitaxial layer is provided with a first groove and the waveguide photodetector epitaxial layer is provided with a second groove. The first groove is located near the first end and the second groove is located near the second end. Both the first groove and the second groove are arranged along the Y-axis direction. The second groove is provided in multiple ways, and the multiple second grooves are spaced apart along the X-axis direction; The depth of the first groove is less than the depth of the second groove; the first groove and the second groove are filled with a medium to alternately form a distributed Bragg reflector with semiconductor material, and a resonant cavity is formed between the first groove and the second groove.

2. The monolithically integrated resonant cavity enhanced waveguide photodetector according to claim 1, characterized in that, The first groove extends from the middle of the photodetector epitaxial layer along the Y-axis toward both ends of the photodetector epitaxial layer; The second groove extends from the middle of the waveguide photodetector epitaxial layer along the Y-axis toward both ends of the photodetector epitaxial layer.

3. The monolithically integrated resonant cavity enhanced waveguide photodetector according to claim 2, characterized in that, The first groove extends from the middle of the epitaxial layer of the photodetector along the Y-axis towards both ends by a distance equal to L1 / 2; The second groove extends from the middle of the epitaxial layer of the waveguide photodetector along the Y-axis towards both ends by a distance equal to L1 / 2; Where L1 is the width of the photodetector epitaxial layer along the Y-axis.

4. The monolithically integrated resonant cavity enhanced waveguide photodetector according to claim 2, characterized in that, The first groove extends from the middle of the epitaxial layer of the photodetector along the Y-axis towards both ends by a distance less than L1 / 2; The second groove extends from the middle of the epitaxial layer of the waveguide photodetector toward both ends by a distance less than L1 / 2 along the Y-axis. Where L1 is the width of the photodetector epitaxial layer along the Y-axis.

5. The monolithically integrated resonant cavity enhanced waveguide photodetector according to claim 1, characterized in that, The first groove includes a first groove body and a second groove body, the first groove body and the second groove body are collinear; the second groove includes a third groove body and a fourth groove body, the third groove body and the fourth groove body are collinear. The first and second grooves extend from the edge of the photodetector epitaxial layer along the Y-axis toward the middle of the photodetector epitaxial layer, and the third and fourth grooves extend from the edge of the photodetector epitaxial layer along the Y-axis toward the middle of the waveguide photodetector epitaxial layer. The first groove and the second groove form a first gap along the Y-axis direction; the third groove and the fourth groove form a second gap along the Y-axis direction.

6. The monolithically integrated resonant cavity enhanced waveguide photodetector according to claim 1, characterized in that, The distance between two adjacent second grooves is Kλ / 4n1; Where K is a positive odd number, λ is the wavelength of the incident light, and n1 is the refractive index of the waveguide layer.

7. The monolithically integrated resonant cavity enhanced waveguide photodetector according to claim 1, characterized in that, The widths of the first groove and the second groove along the X-axis are equal, both being Nλ / 4n2; Where N is a positive odd number, λ is the wavelength of the incident light, and n2 is the refractive index of the medium in the first groove and the second groove.

8. The monolithically integrated resonant cavity enhanced waveguide photodetector according to claim 1, characterized in that, The epitaxial layer of the photodetector includes a collection layer, a cliff layer, a spacer layer, an absorption layer, an electron blocking layer, and a P-contact layer; The collecting layer, the cliff layer, the spacer layer, the absorption layer, the electron blocking layer, and the P contact layer are arranged sequentially along the Z-axis direction. The collecting layer is connected to the waveguide layer, and the P contact layer is connected to the P metal electrode.

9. The monolithically integrated resonant cavity enhanced waveguide photodetector according to claim 1, characterized in that, The cross-sectional shape of the first groove and the second groove on the plane perpendicular to the Y-axis is square.

Images