Polarization signal amplification photoelectric detector based on gallium oxide and preparation method thereof

Abstract

The invention provides a polarization signal amplification photoelectric detector based on gallium oxide and a preparation method thereof. The polarization signal amplification photoelectric detector based on gallium oxide comprises a gallium oxide single crystal substrate; the gallium oxide photoelectric detector is arranged on the gallium oxide single crystal substrate, and the gallium oxide photoelectric detector is configured to generate different photoelectric responses to the solar-blind ultraviolet light in different polarization directions by using the in-plane anisotropy of a gallium oxide material and output electric signals changing along with the polarization directions; the gallium oxide transistor is arranged on the gallium oxide single crystal substrate, a grid electrode of the gallium oxide transistor is electrically connected with the signal output end of the gallium oxide photoelectric detector so as to receive an electric signal changing along with the polarization direction to serve as input of the grid electrode, the gallium oxide transistor works in a sub-threshold region, and the change of the polarization direction causes the change of grid electrode voltage; and an electric signal with enhanced amplitude is output from the drain electrode of the gallium oxide transistor, so that on-chip amplification of the polarization signal is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor devices, and particularly relates to a gallium oxide-based polarization signal amplification photodetector and a preparation method thereof. BACKGROUND

[0002] Compared with a traditional photodetector, a polarization photodetector can increase a detection dimension, and improve detection accuracy by acquiring and analyzing polarization information. Early polarization photodetectors include time-sharing polarization photodetectors, amplitude-sharing polarization photodetectors, and aperture-sharing polarization photodetectors, which realize polarization light detection through different optical elements and structural designs. In recent years, with the development of integration, polarization photodetectors gradually evolve towards miniaturization and integration. A mainstream integrated scheme is to use a subwavelength metal grating structure in a focal plane, but this method has a high requirement for micro-nano processing technology, especially in the solar blind ultraviolet band. In addition, crosstalk is prone to occur between different polarization units, which reduces the extinction ratio. Therefore, it is an important research topic for those skilled in the art to realize high-sensitivity detection of solar blind ultraviolet polarization light and on-chip amplification of polarization signals, while reducing the integration complexity and process difficulty of the device. SUMMARY

[0003] Therefore, the present application provides a gallium oxide-based polarization signal amplification photodetector and a preparation method thereof, which integrates a gallium oxide photodetector and a gallium oxide transistor to prepare a polarization signal amplification photodetector with high detection accuracy, so as to expand the application of the gallium oxide polarization photodetector.

[0004] In one aspect, the present application provides a gallium oxide-based polarization signal amplification photodetector, which comprises: a gallium oxide single crystal substrate; a gallium oxide photodetector arranged on the gallium oxide single crystal substrate, the gallium oxide photodector uses the in-plane anisotropy of gallium oxide material to produce different photoelectric responses to solar blind ultraviolet light with different polarization directions, and outputs an electric signal varying with the polarization direction; and a gallium oxide transistor arranged on the gallium oxide single crystal substrate, a gate electrode of the gallium oxide transistor is electrically connected with a signal output end of the gallium oxide photodetector to receive the electric signal varying with the polarization direction as an input of the gate electrode, the gallium oxide transistor works in a subthreshold region, the polarization direction variation causes a gate voltage variation, and then an electric signal with an enhanced amplitude is output from a drain electrode of the gallium oxide transistor, so as to realize on-chip amplification of the polarization signal.

[0005] According to the present application, the gallium oxide single crystal substrate is a beta-type (001) surface single crystal gallium oxide substrate.

[0006] According to the present application, the gallium oxide photodetector is provided with an interdigital electrode structure, one end of the interdigital electrode structure is an ohmic contact electrode, the other end is a Schottky contact electrode, and the ohmic contact electrode and the Schottky contact electrode form a Schottky junction on the surface of the gallium oxide.

[0007] According to the embodiment of the present application, the gallium oxide transistor comprises an n-type well formed on a gallium oxide single crystal substrate, a source, a drain and a gate of the gallium oxide transistor are located in an area where the n-type well is located, the source and the drain form ohmic contacts with the gallium oxide semiconductor respectively, and the gate is isolated from a channel region by a dielectric layer.

[0008] According to the embodiment of the present application, the n-type well is formed by ion implantation of silicon, and a multi-dose and energy implantation mode is used to achieve uniform doping, and high-temperature annealing in a nitrogen atmosphere is used to activate the doping and repair lattice damage.

[0009] According to the embodiment of the present application, the source and the drain of the gallium oxide transistor are made of a metal material with a work function matched to that of the n-type well, so that the source and the drain form ohmic contacts with the n-type well.

[0010] According to the embodiment of the present application, a metal interconnection line is further included, which connects a signal output end of the gallium oxide photodetector and the gate of the gallium oxide transistor, and the contact area of the metal interconnection line with the electrode is greater than the area of the electrode itself, so as to reduce the contact resistance.

[0011] According to the embodiment of the present application, a gallium oxide resistor integrated on the gallium oxide single crystal substrate is further included, the gallium oxide resistor is connected to a bias circuit through a metal interconnection line, and the gallium oxide resistor is used to adjust the working voltage of the gallium oxide photodetector or the gallium oxide transistor.

[0012] According to the embodiment of the present application, an isolation layer is arranged between the light absorption layer of the gallium oxide photodetector and the device region of the gallium oxide transistor, the isolation layer forms a mesa structure through an etching process, and electrical isolation between devices is achieved.

[0013] The embodiment of the present application further provides a preparation method of the polarization signal amplification photodetector of any one of the above embodiments, which comprises the following steps: etching a light absorption layer of a gallium oxide photodetector and a substrate mesa of a gallium oxide transistor on a gallium oxide single crystal substrate by using an inductively coupled plasma etching process, depositing a silicon oxide layer on the gallium oxide single crystal substrate by using a plasma enhanced chemical vapor deposition process to perform mesa isolation, removing the silicon oxide layer above an n-type well by using a photolithography and etching process to form an ion implantation mask, obtaining an n-type well with uniform ion concentration in a selected area by using a multi-implantation mode, depositing a metal by using an electron beam evaporation, forming an interdigital electrode structure, a source, a drain, a gate, a gallium oxide resistor and a metal interconnection line connecting the gallium oxide photodetector and the gate of the gallium oxide transistor by using a photolithography and stripping process, and completing monolithic integration of the device.

[0014] The polarized signal amplification photoelectric detector and the preparation method thereof have at least the following beneficial effects: the in-plane anisotropy of the gallium oxide material is utilized, the gallium oxide photoelectric detector can directly identify solar blind ultraviolet light with different polarization directions, no additional polarization element is needed, and the system structure is simplified. The polarization-related electrical signal output by the detector is directly input to the gate of the gallium oxide transistor through the interconnection structure, the transistor works in the sub-threshold region, can amplify the slight voltage change caused by the polarization change with high gain, and significantly improves the amplitude and polarization contrast of the output signal. The whole device realizes monolithic integration of detection and amplification functions based on the same gallium oxide single crystal substrate, has good process compatibility, small size and high stability, and is beneficial to realize a high-performance, miniaturized solar blind ultraviolet polarized light detection system. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more completely understand the present application and its advantages, reference will now be made to the following description taken together with the accompanying drawings, in which:

[0016] Figure 1 An electric circuit structure schematic diagram of a gallium oxide-based polarized signal amplification photoelectric detector provided by an embodiment of the present application is illustratively shown;

[0017] Figure 2 A structure schematic diagram of a gallium oxide transistor in a gallium oxide-based polarized signal amplification photoelectric detector provided by an embodiment of the present application is illustratively shown;

[0018] Figure 3A A top view of a gallium oxide photoelectric detector in a gallium oxide-based polarized signal amplification photoelectric detector provided by an embodiment of the present application is illustratively shown;

[0019] Figure 3B A front view of a gallium oxide photoelectric detector in a gallium oxide-based polarized signal amplification photoelectric detector provided by an embodiment of the present application is illustratively shown;

[0020] Figure 4 A flowchart of a preparation method of a gallium oxide-based polarized signal amplification photoelectric detector provided by an embodiment of the present application is illustratively shown.

[0021] Explanation of reference signs:

[0022] 10 - interconnection structure;

[0023] 11 - voltage bias;

[0024] 12 - gallium oxide photoelectric detector;

[0025] 13 - gallium oxide resistor;

[0026] 14 - gallium oxide transistor;

[0027] 15 - polarized signal analyzer;

[0028] 16 - gallium oxide transistor substrate;

[0029] 17 - n-type well;

[0030] 18 - source;

[0031] 19 - drain;

[0032] 20 - gate;

[0033] 21 - dielectric layer;

[0034] 22 - gallium oxide photodetector substrate;

[0035] 23 - Schottky contact electrode;

[0036] 24 - ohmic contact electrode. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. It should be understood, however, that the description which follows is merely illustrative and is not intended to limit the scope of the present application. In the following detailed description of embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that one or more embodiments of the present application can be practiced without these specific details. In other instances, well-known structures and

[0038] The terms used herein are merely used to describe specific embodiments and are not intended to limit the present application. The terms "include", "comprise" and the like used herein indicate the presence of features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0039] All terms used herein, including technical and scientific terms, have the same meanings as those generally understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having meanings consistent with the context of the present specification, and should not be interpreted in an idealized or overly formal manner.

[0040] As Figure 1As shown, a gallium oxide-based polarization signal amplification photodetector is provided. The polarization signal amplification photodetector can include a gallium oxide photodetector 12 and a gallium oxide transistor 14. The gallium oxide photodetector 12 and the gallium oxide transistor 14 are disposed on the same gallium oxide single crystal substrate, and the gallium oxide photodetector 12 is configured to produce different photoelectric responses to solar blind ultraviolet light of different polarization directions by utilizing the in-plane anisotropy of the gallium oxide material, and output an electric signal varying with the polarization direction. The gallium oxide transistor 14 includes a gate, a source and a drain. The gate of the gallium oxide transistor 14 is electrically connected to the signal output end of the gallium oxide photodetector 12 through an interconnection structure 10 to receive the electric signal varying with the polarization direction as a gate input. The gallium oxide transistor 14 operates in a sub-threshold region, and the change in the polarization direction causes the change in the gate voltage of the gallium oxide transistor 14, and then an electric signal with enhanced amplitude is output from the drain of the gallium oxide transistor 14 to realize on-chip amplification of the polarization signal.

[0041] The gallium oxide-based polarization signal amplification photodetector of the present embodiment utilizes the in-plane anisotropy of the gallium oxide material, and the gallium oxide photodetector can directly identify solar blind ultraviolet light of different polarization directions without additional polarization elements, thus simplifying the system structure. The polarization-related electric signal output by the photodetector is directly input to the gate of the gallium oxide transistor through the interconnection structure, and the transistor operates in a sub-threshold region, which can amplify the slight voltage change caused by the change in the polarization direction with high gain, thus significantly improving the amplitude and polarization contrast of the output signal. The entire device realizes monolithic integration of the detection and amplification functions based on the same gallium oxide single crystal substrate, has good process compatibility, small size and high stability, and is conducive to realizing a high-performance and miniaturized solar blind ultraviolet polarization photodetection system.

[0042] In some embodiments, the gallium oxide single crystal substrate can be a β-type (001) plane single crystal gallium oxide. The β-phase gallium oxide has a band gap as high as 4.9 eV, and the optical absorption edge is located in the range of 240-280 nm. The β-phase gallium oxide belongs to a monoclinic system, and the atomic arrangement of different crystal planes is different, and all have in-plane anisotropy. Among them, the in-plane anisotropy of the (001) plane is the strongest, and the photodetector prepared based on this crystal plane has a higher anisotropic polarization ratio. Therefore, by using the β-type (001) plane single crystal gallium oxide substrate and utilizing its intrinsic in-plane anisotropy, the response difference of solar blind ultraviolet light of different polarization directions can be significantly enhanced, and the polarization recognition capability can be improved.

[0043] Please continue to refer to Figure 1 In some embodiments, the interconnection structure 10 can be a metal interconnection line for connecting the signal output end of the gallium oxide photodetector and the gate of the gallium oxide transistor, and the contact area of the metal interconnection line and the electrode is greater than the area of the electrode itself to reduce the contact resistance. By providing the metal interconnection line and increasing the contact area, the connection resistance and signal loss can be effectively reduced to ensure efficient transmission of the weak polarization signal.

[0044] As shown in Figure 1 , the polarization signal amplification photodetector further includes a gallium oxide resistor 13 integrated on the gallium oxide single crystal substrate. The gallium oxide resistor 13 is connected to the bias circuit through a metal interconnection line. The gallium oxide resistor 13 is used to adjust the operating voltage of the gallium oxide photodetector 12 or the gallium oxide transistor 14. By integrating the gallium oxide resistor 13 and connecting it to the bias circuit, the operating voltage of the detector and the transistor can be precisely adjusted, improving the stability and adjustability of the system.

[0045] As shown in Figure 1 , the polarization signal amplification photodetector can be connected to a polarization signal analyzer 15. The polarization signal analyzer 15 can be used to receive and process the amplified electrical signals output from the gallium oxide transistor. These signals contain the polarization information of the original incident light. By analyzing these signals, the polarization state of the light (such as linear polarization, circular polarization or elliptical polarization) and its related parameters (such as degree of polarization, polarization angle, etc.) can be determined.

[0046] In some embodiments, an isolation layer is provided between the light absorption layer of the gallium oxide photodetector 12 and the device region of the gallium oxide transistor 14. For example, it can be a silicon oxide isolation layer. The isolation layer forms a mesa structure through etching process, achieving electrical isolation between devices, effectively preventing inter-device leakage, and ensuring the independence and reliability of integrated devices.

[0047] Figure 2 The structure of the gallium oxide transistor 14 in a gallium oxide-based polarization signal amplification photodetector is schematically shown.

[0048] As shown in Figure 2 , the gallium oxide transistor 14 includes a gallium oxide transistor substrate 16, an n-type well 17, a source 18, a drain 19, a gate 20 and a dielectric layer 21. The gallium oxide transistor substrate 16 is part of the gallium oxide single crystal substrate, serving as the base layer of the entire device, providing mechanical support and electrical isolation. The n-type well 17 is formed on the gallium oxide transistor substrate 16, used to form the source and drain regions of the transistor, improving the carrier concentration and conductivity. The source 18 and the drain 19 are connected to the n-type well 17 through ohmic contact. The gate 20 is located between the source 18 and the drain 19, and by controlling the gate voltage, the number of carriers in the channel is adjusted, thereby controlling the flow of current. The dielectric layer 21 covers the gallium oxide transistor substrate 16 and the n-type well 17, ensuring effective control of the gate over the channel.

[0049] In some embodiments, the n-type well 17 can be implanted with silicon (Si) ions, employing multiple implantation doses and energies to achieve uniform doping, followed by high-temperature annealing in a nitrogen atmosphere to activate the doping and repair lattice damage. For example, uniform doping ion concentration can be obtained through three stages of different implantation energies and doses. By using multi-dose, multi-energy silicon ion implantation combined with high-temperature annealing, uniform doping of the n-type well and lattice damage repair can be achieved, improving the electrical performance and process consistency of the transistor.

[0050] In some embodiments, the source 18 and drain 19 of the gallium oxide transistor 14 are made of a work function-matched metal material so that the source 18, drain 19 and n-type well 17 form an ohmic contact. This reduces the contact resistance between the source 18 and drain 19, improving the conduction capability and signal amplification efficiency of the gallium oxide transistor 14.

[0051] In some embodiments, the material and thickness of the dielectric layer 21 can be confirmed by software simulation, and the present invention does not impose specific limitations.

[0052] Figure 3A The schematic diagram shows a top view of a gallium oxide photodetector 12 in a gallium oxide-based polarization signal amplification photodetector provided in an embodiment of the present invention. Figure 3B The illustration shows a front view of a gallium oxide photodetector 12 in a gallium oxide-based polarization signal amplification photodetector provided in an embodiment of the present invention.

[0053] like Figure 3A and Figure 3B As shown, the gallium oxide photodetector 12 may include a gallium oxide photodetector substrate 22, a Schottky contact electrode 23, and an ohmic contact electrode 24. The gallium oxide photodetector substrate 22 is part of a gallium oxide single-crystal substrate and serves as the base layer of the entire device, providing mechanical support and electrical isolation. Figure 3A As shown, the Schottky contact electrode 23 and the ohmic contact electrode 24 form an interdigitated electrode structure, and the ohmic contact electrode 24 and the Schottky contact electrode 23 form a Schottky junction on the gallium oxide surface. The electrode material can be a metal that matches the work function of the substrate, forming Schottky contacts and ohmic contacts respectively, so that the photodetector exhibits a Schottky rectification effect. By setting the interdigitated electrode structure and forming a Schottky junction, the separation efficiency and response speed of photogenerated carriers can be effectively improved, and the sensitivity of the photodetector can be enhanced.

[0054] According to an embodiment of the present invention, a gallium oxide-based polarization signal amplification photodetector is provided. The present invention also designs a polarization scanning imaging system to verify the polarization signal amplification function of the device. By scanning images at different polarization angles using the imaging system and comparing the grayscale values ​​of the images, the polarization signal amplification effect of the device is qualitatively analyzed, and the application prospects of the device in polarization imaging are explored.

[0055] In some embodiments, the application of the gallium oxide-based polarization signal amplification photodetector provided by the embodiments of the application to polarization light scanning imaging can include three parts of light source selection, imaging system design and scanning system design.

[0056] In terms of light source selection, a solar blind ultraviolet band surface array light source can be used, and the solar blind ultraviolet light with large and uniform output power can be obtained, and then the polarized light with adjustable polarization direction can be obtained after passing through a polarizer and a half-wave plate.

[0057] In terms of imaging system design, the polarized light can be irradiated onto a metal pattern plate, the outgoing light carrying image information can pass through a solar blind ultraviolet lens group, and the polarization amplification photodetector can be placed at the focal plane position after the lens group, the photodetector can convert the light signal into an electrical signal, and finally the output can be in the form of a gray value.

[0058] In terms of scanning system design, since the area of the photodetector is small, the photodetector can be controlled to move on the focal plane by a stepping motor until all the image information is collected, different polarization information images can be obtained by changing the direction of the polarized light, and the polarization ratio amplification effect of the photodetector can be verified.

[0059] Based on the gallium oxide-based polarization signal amplification photodetector provided in the above embodiments, the application further provides a preparation method of the gallium oxide-based polarization signal amplification photodetector. Figure 4 A flowchart of the preparation method of the gallium oxide-based polarization signal amplification photodetector provided by the embodiments of the application is schematically shown.

[0060] As shown in Figure 4 The preparation method of the gallium oxide-based polarization signal amplification photodetector can include steps S410-S430.

[0061] In step S410, an inductively coupled plasma etching (ICP) process is used to etch a gallium oxide photodetector light absorption layer and a gallium oxide transistor substrate mesa on a gallium oxide single crystal substrate, and a plasma enhanced chemical vapor deposition (PECVD) process is used to deposit a silicon oxide layer on the gallium oxide single crystal substrate for mesa isolation.

[0062] In some embodiments, after etching the gallium oxide single crystal substrate, a chemical solvent can be used to repair the surface of the light absorption layer and the substrate mesa of the transistor.

[0063] In step S420, the silicon oxide layer above the n-type well is removed by a photolithography and etching process to form an ion implantation mask, and a uniform ion concentration n-type well is obtained by multiple implantation in the selected area.

[0064] In some embodiments, when preparing the n-type well, silicon oxide can be used as a hard mask, and the ion implantation window distance can be determined by simulation. It is worth noting that too small spacing can cause transistor short circuit, and too large spacing can cause transistor quality to decrease.

[0065] In step S430, the metal is deposited by electron beam evaporation, the interdigital electrode structure, the source, the drain, the gate, the gallium oxide resistance and the metal interconnection line connecting the gallium oxide photodetector and the gallium oxide transistor gate are formed through a photolithography and stripping process, and the monolithic integration of the device is completed.

[0066] Specifically, the electrode metal is deposited by electron beam deposition, the electrodes of the photodetector are interdigital electrode structures, the metal material with a matched work function is selected to form ohmic contact and Schottky contact respectively, the Schottky photodetector is prepared, the source, the drain and the gate of the transistor form ohmic contact with the semiconductor respectively, the metal interconnection line is prepared by using a photolithography process to prepare a metal interconnection line pattern, the contact area of the metal interconnection line and the electrode is greater than the area of the electrode to prevent leakage, a metal with a suitable thickness is evaporated by using an electron beam, and finally the electrode pattern is stripped out. After the metal is evaporated by using an electron beam, in the case that the edge topography of the stripped electrode is irregular, the photolithography process can be improved, and a double-layer glue is used in the glue uniformization process to achieve a better stripping effect.

[0067] In the embodiment, after the preparation of the gallium oxide-based polarization signal amplification photodetector is completed, photoelectric performance testing needs to be performed, the responsivity, the detectivity and the response time of the photodetector are tested under the irradiation of the solar blind ultraviolet waveband light. Under the irradiation of the solar blind ultraviolet linearly polarized light, the polarization degree of the ordinary gallium oxide photodetector and the polarization signal amplification gallium oxide photodetector is tested respectively, and the polarization signal amplification effect is preliminarily verified through the comparison of the polarization ratios in the test results.

[0068] The preparation method provided in the embodiment of the application has a simple whole process, the polarization ratio of the polarization photodetector is optimized through circuit structure design, a larger polarization ratio can improve the quality of the polarization imaging image, and the application range of the polarization photodetector is expanded.

[0069] Those skilled in the art can understand that the features described in various embodiments and / or claims of the present application can be combined or / and integrated in various combinations, even if such combinations or integrations are not explicitly described in the present application. In particular, the features described in various embodiments and / or claims of the present application can be combined and / or integrated in various combinations without departing from the spirit and teachings of the present application. All these combinations and / or integrations fall within the scope of the present application.

[0070] While the application has been shown and described with reference to particular exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the application as defined by the appended claims and their equivalents. Therefore, the scope of the application should not be limited to the embodiments described herein but should be accorded the full scope of the appended claims and their equivalents.

Claims

1. A gallium-oxide-based polarization signal amplification photodetector, characterized by, include: Gallium oxide single crystal substrate; A gallium oxide photodetector is disposed on the gallium oxide single crystal substrate. The gallium oxide photodetector is configured to utilize the in-plane anisotropy of gallium oxide material to generate different photoelectric responses to solar-blind ultraviolet light with different polarization directions, and output an electrical signal that varies with the polarization direction. A gallium oxide transistor is disposed on the gallium oxide single crystal substrate. The gate of the gallium oxide transistor is electrically connected to the signal output terminal of the gallium oxide photodetector to receive the electrical signal that varies with the polarization direction as the input of the gate. The gallium oxide transistor operates in the subthreshold region. The change in polarization direction causes a change in the gate voltage, thereby outputting an enhanced electrical signal from the drain of the gallium oxide transistor to realize on-chip amplification of the polarization signal.

2. The polarization signal amplification photodetector according to claim 1, wherein, The gallium oxide single crystal substrate is a β-type (001) plane single crystal gallium oxide substrate.

3. The polarization signal amplification photodetector of claim 1, wherein, The gallium oxide photodetector has an interdigitated electrode structure, one end of which is an ohmic contact electrode and the other end is a Schottky contact electrode. The ohmic contact electrode and the Schottky contact electrode form a Schottky junction on the surface of gallium oxide.

4. The polarization signal amplification photodetector of claim 1, wherein, The gallium oxide transistor includes: An n-type well is formed on the gallium oxide single crystal substrate. The source, drain, and gate of the gallium oxide transistor are located in the region of the n-type well. The source and drain form ohmic contacts with the gallium oxide semiconductor, and the gate is isolated from the channel region through a dielectric layer.

5. The polarization signal amplification photodetector according to claim 4, wherein, The n-type well is formed by silicon ion implantation, and multiple dose and energy implantation methods are used to achieve uniform doping. The doping is activated and lattice damage is repaired by high-temperature annealing in a nitrogen atmosphere.

6. The polarization signal amplification photodetector of claim 4, wherein, The source and drain of the gallium oxide transistor are made of work function-matched metal materials so that the source, drain and n-type well form an ohmic contact.

7. The polarization signal amplification photodetector of claim 1, wherein, It also includes a metal interconnect connecting the signal output terminal of the gallium oxide photodetector to the gate of the gallium oxide transistor, and the contact area between the metal interconnect and the electrode is larger than the area of ​​the electrode itself, so as to reduce the contact resistance.

8. The polarization signal amplification photodetector according to claim 7, wherein, It also includes a gallium oxide resistor integrated on the gallium oxide single crystal substrate, the gallium oxide resistor being connected to a bias circuit via the metal interconnect, and the gallium oxide resistor being used to adjust the operating voltage of the gallium oxide photodetector or the gallium oxide transistor.

9. The polarization signal amplification photodetector of claim 1, wherein, An isolation layer is provided between the light absorption layer of the gallium oxide photodetector and the device region of the gallium oxide transistor. The isolation layer is formed into a mesa structure by an etching process to achieve electrical isolation between the devices.

10. A method of fabricating a polarization signal amplifying photodetector according to any one of claims 1-9, characterized by, include: The light absorption layer of the gallium oxide photodetector and the substrate mesa of the gallium oxide transistor are etched on the gallium oxide single crystal substrate using inductively coupled plasma etching (ICP-CED). A silicon oxide layer is then deposited on the gallium oxide single crystal substrate using plasma-enhanced chemical vapor deposition (PECVD) to isolate the mesa. The silicon oxide layer above the n-type well is removed by photolithography and etching processes to form an ion implantation mask. In a selected area, an n-type well with uniform ion concentration is obtained by multiple implantation. The metal is deposited by electron beam evaporation, and an interdigital electrode structure, a source, a drain, a gate, a gallium oxide resistance and a metal interconnection line connecting the gallium oxide photodetector and the gallium oxide transistor gate are formed through a photolithography and stripping process, so that monolithic integration of the device is completed.

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