Gallium oxide detector, method of making and use thereof

Abstract

The application discloses a gallium oxide detector, a preparation method and application thereof. The gallium oxide detector comprises a high work function metal barrier layer, a gallium oxide layer and a channel layer which are sequentially stacked, a bottom electrode which is electrically connected with a Ge film and is electrically isolated from the high work function metal barrier layer and the gallium oxide layer, and a top electrode which is arranged on the channel layer, wherein the channel layer comprises the Ge film. The application adopts a device structure design in which an absorption region and a carrier drift region are separated, the gallium oxide layer is only used as a light absorption layer, and current is mainly distributed in the Ge channel, so that the limitation of low carrier mobility and hole self-confinement effect of the gallium oxide can be effectively avoided, the high work function thin metal is introduced as a barrier layer, the ability of high-speed transmission of electrons of Ge can be fully utilized, the response of the device to holes with low mobility is avoided, and finally a high-speed and high-sensitivity solar blind ultraviolet detector is realized.

Description

Technical Field

[0001] This application relates to a photodetector, specifically a high-speed, ultrasensitive gallium oxide (Ga2O3) detector, its preparation method and application, belonging to the field of photodetector technology. Background Technology

[0002] Due to the absorption effect of the ozone layer, background ultraviolet light in the UVC band (<280 nm) is almost non-existent in nature, which gives UVC band detection extremely high signal-to-noise ratio and low false alarm rate. UVC band ultraviolet light is also known as solar-blind ultraviolet light, and solar-blind ultraviolet detection has shown great application potential in optical imaging, ozone hole detection, missile guidance and early warning, secure space communication, and corona detection. Gallium oxide, as a natural solar-blind ultraviolet material, boasts a band gap (4.9 eV) that matches the solar-blind band, reaching up to 10... 5 cm -1 Its light absorption coefficient and the ability to obtain single crystals via the Czochralski method make it a highly promising candidate for solar-blind ultraviolet detectors.

[0003] However, gallium oxide is limited by its inherent electrical properties, making it difficult to achieve high-speed, high-bandwidth response capabilities, which hinders its development in fields such as early warning and optical communication. For example, due to the influence of phonon scattering, the theoretical electron mobility limit of gallium oxide is 300 cm⁻¹. 2 Given that the device's RC constant is approximately / V·s, its frequency bandwidth is around kHz, thus the response time is often difficult to achieve below the μs level. Secondly, due to the flat valence band of gallium oxide (GaO), the effective hole mass is extremely high, resulting in extremely low hole mobility and even significant hole self-binding. These two phenomena together limit GaO's application in high-speed and high-frequency fields. Although research has shown that doping GaO with the transition metal iridium (Ir) can tune the valence band EK dispersion relation and reduce the effective hole mass, Ir is expensive, and valence band tuning causes a redshift in the GaO absorption edge, reducing its solar-blind response capability.

[0004] Existing gallium oxide-based solar-blind ultraviolet detector device structures mainly include two-terminal types, such as photoconductive, Schottky diode, metal-semiconductor-metal (MSM), and pn heterojunction types; and three-terminal types, such as MOSFETs. These device structures have certain advantages in achieving high-speed or high-sensitivity responses, but they fail to fundamentally overcome the limitations imposed by the inherent electrical properties of gallium oxide. The main reason is that these device structures not only use gallium oxide as the light absorption region but also as the conductive channel. The carrier mobility is limited by phonon scattering and self-binding effects, resulting in a low theoretical limit for the devices. Therefore, it is inherently difficult for these devices to achieve high-speed, wide-bandwidth responses. Summary of the Invention

[0005] The main objective of this application is to provide a gallium oxide detector, its fabrication method, and its application, in order to overcome the shortcomings of the prior art.

[0006] To achieve the above objectives, this application adopts the following technical solution.

[0007] The first aspect of this application provides a gallium oxide detector, comprising: A high work function metal barrier layer, a gallium oxide layer, and a channel layer are sequentially stacked, wherein the channel layer includes a Ge thin film; The bottom electrode is electrically connected to the Ge thin film; A passivation layer is disposed between the bottom electrode and the high work function metal barrier layer and the gallium oxide layer, and electrically isolates the bottom electrode from the high work function metal barrier layer and the gallium oxide layer; The top electrode is electrically connected to the channel layer.

[0008] A second aspect of this application provides a method for fabricating the gallium oxide detector, comprising: A high work function metal barrier layer and a gallium oxide layer are sequentially formed on a light-transmitting substrate; A passivation layer is formed on the light-transmitting substrate, so that the passivation layer electrically isolates the high work function metal barrier layer and the gallium oxide layer from the bottom electrode; A bottom electrode is disposed on the light-transmitting substrate; A Ge thin film is disposed on the gallium oxide layer to form a channel layer, and the Ge thin film is electrically connected to the bottom electrode; A top electrode is disposed on the channel layer and electrically connected to the channel layer.

[0009] A third aspect of this application provides the use of the gallium oxide detector in ultraviolet light, particularly solar-blind ultraviolet light. In some cases, the gallium oxide detector can be used as a solar-blind ultraviolet detector.

[0010] A fourth aspect of this application provides an ultraviolet light detection method, comprising: detecting solar-blind ultraviolet light using the gallium oxide detector. Compared with existing technologies, the gallium oxide detector of this application adopts a device structure design that separates the absorption region and the carrier drift region. The gallium oxide layer is used only as a light absorption layer, and the current is mainly distributed in the Ge channel. Therefore, it can effectively avoid the limitations of low carrier mobility and hole self-binding effect of gallium oxide. At the same time, by introducing a thin metal with high work function as a barrier layer, only photogenerated electrons are used to form photocurrent, and the band structure of gallium oxide / Ge heterojunction is changed. This causes electrons in the light absorption region of gallium oxide to drift to the channel Ge, while holes accumulate on the surface of the gallium oxide thin film. This not only utilizes the ability of Ge to transport electrons at high speed, but also avoids the low mobility of holes from affecting the device response. Ultimately, a high-speed and high-sensitivity solar-blind ultraviolet detector can be realized. Attached Figure Description

[0011] Figure 1 This is a cross-sectional view of a gallium oxide detector according to Embodiment 1 of this application; Figure 2 yes Figure 1 The top view of the gallium oxide detector shown; Figure 3 This is a schematic diagram of the current path when the diameter of the top electrode is larger than the diameter of the gallium oxide layer; Figure 4 This is a schematic diagram of the fabrication process of a gallium oxide detector according to Embodiment 1 of this application; Figure 5 This is a cross-sectional view of a gallium oxide detector according to Embodiment 2 of this application; Figure 6 yes Figure 5 The top view of the gallium oxide detector shown; Figure 7 This is a schematic diagram of the fabrication process of a gallium oxide detector according to Embodiment 2 of this application; Figure 8 This is a cross-sectional view of a gallium oxide detector according to Embodiment 3 of this application; Figure 9 , Figure 10 This is a schematic diagram of the fabrication process of a gallium oxide detector according to Embodiment 3 of this application; Figure 11 This is a schematic diagram of a simulated structure of a gallium oxide detector according to one embodiment of this application; Figure 12 yes Figure 11 A schematic diagram of the band structure along the dashed line A; Figure 13 It is Figure 11 The diagram shows the band structure along dashed line A in the gallium oxide detector, with the Ni barrier layer omitted. Figure 14 This is a contour plot of the total current density distribution of a gallium oxide detector according to an embodiment of this application; Figure 15 This is a cross-sectional schematic diagram of a conventional gallium oxide detector in Comparative Example 1; Figure 16 These are the curves showing the change of photocurrent as a function of voltage for the gallium oxide detectors in Examples 1, 2, and 3, and the gallium oxide detector in Comparative Example 1. Figure 17 These are curves showing the change of photocurrent over time for the gallium oxide detectors in Examples 1, 2, and 3, as well as the gallium oxide detector in Comparative Example 1. Detailed Implementation

[0012] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] Some embodiments of this application provide a gallium oxide detector, including: A high work function metal barrier layer, a gallium oxide layer, and a channel layer are sequentially stacked, wherein the channel layer includes a Ge thin film; The bottom electrode is electrically connected to the Ge thin film; A passivation layer is disposed between the bottom electrode and the high work function metal barrier layer and the gallium oxide layer, and electrically isolates the bottom electrode from the high work function metal barrier layer and the gallium oxide layer; The top electrode is electrically connected to the channel layer.

[0014] The absorption region of the gallium oxide detector in this application is composed of gallium oxide, while the carrier drift region is composed of a material with high electron mobility, such as germanium (Ge), thus separating the light absorption region and the carrier drift region. By optimizing the band structure, photogenerated electrons in gallium oxide drift into Ge under illumination and are subsequently collected by the electrodes at both ends of Ge. Photogenerated holes accumulate in gallium oxide until their generation and recombination processes reach a dynamic equilibrium. Since gallium oxide is used only as a light absorption layer, the current is mainly distributed in the Ge channel, thereby effectively avoiding the limitations imposed by the low carrier mobility and hole self-binding effect of gallium oxide. Meanwhile, the gallium oxide detector of this application uses a high work function metal (such as Ni, Pt or Au) as a barrier layer, and only utilizes photogenerated electrons to form photocurrent. It also changes the band structure of the Ga2O3 / Ge heterojunction, causing electrons in the light absorption region Ga2O3 to drift to the channel Ge, while holes accumulate on the surface of the Ga2O3 thin film. This not only utilizes the ability of Ge to transport electrons at high speed, but also avoids the low mobility of holes affecting the device response.

[0015] More preferably, the channel layer may further include: The heavily doped ring band is formed by doping a designated annular region within the Ge thin film with a first donor impurity, and is electrically in contact with the gallium oxide layer and the top electrode, while being electrically isolated from the bottom electrode.

[0016] The gallium oxide detector of this application introduces near-surface heavily doped rings within the Ge thin film by setting the aforementioned heavily doped rings. This enhances the built-in electric field at the interface, making the band bending more conducive to electron injection from gallium oxide into the Ge thin film and accelerating its drift transport. Simultaneously, the ring-shaped distribution also brings a slight radial potential convergence effect, allowing injected electrons to converge more efficiently into the electrode path, thereby improving the overall photogenerated electron collection efficiency and response speed.

[0017] Furthermore, the doping concentration of the first donor impurity within the heavily doped ring is preferably 1×10⁻⁶. 17 cm -3 ~ 1×10 18 cm -3 .

[0018] Furthermore, the first donor impurity may include, but is not limited to, one or more combinations of phosphorus, antimony, and arsenic.

[0019] Furthermore, the passivation layer has a ring structure, with the outer diameter of the heavily doped ring being smaller than the inner diameter of the passivation layer to prevent short circuits between the top and bottom electrodes. Simultaneously, the inner diameter of the heavily doped ring is smaller than the diameter of the top electrode to cover the region where the peak current density is located.

[0020] Furthermore, the heavily doped ring band is parallel to the central axis of the top electrode.

[0021] Furthermore, the heavily doped ring band is coaxially arranged with the top electrode.

[0022] In one embodiment, the interface between the gallium oxide layer and the channel layer is a radially gradient depth surface. For example, the central region of the interface between the gallium oxide layer and the channel layer is recessed or protrudes away from the top electrode.

[0023] Due to the positional deviation of the top and bottom electrodes of the gallium nitride detector in this application, although the gallium nitride detector in this application is a vertical structure device, the current transmission path is not vertical. By making the interface between the gallium oxide layer and the channel layer curved, especially a radially gradient depth curved surface, the distribution of local electric field lines can be changed, so that the electric field is "focused" from the edge to the center or from the center to the top at the gallium oxide / Ge interface, thereby enhancing the vertical / radial coupling field components, helping photogenerated electrons to be "pulled out" of gallium oxide and move to the collection electrode via Ge, thereby further improving the device performance.

[0024] Preferably, the interface between the gallium oxide layer and the channel layer, the heavily doped ring, and the top electrode are coaxially arranged so that the above-mentioned multiple effects can be generated synergistically, thereby further improving the current generation and collection efficiency in the device and more effectively optimizing the device's sensitivity and response speed.

[0025] In one embodiment, the diameter of the top electrode is smaller than the diameter of the gallium oxide layer; otherwise, a large dark current will be generated in the gallium oxide detector, thereby reducing the photoresponse of the device.

[0026] In one embodiment, the gallium oxide detector further includes a light-transmitting substrate, wherein the high work function metal barrier layer, the gallium oxide layer, and the channel layer are sequentially disposed on the top surface of the light-transmitting substrate, and the top surface of the light-transmitting substrate is a radially gradient depth curved surface. Using this light-transmitting substrate allows the interface between the gallium oxide layer and the channel layer formed on the top surface of the light-transmitting substrate to have the aforementioned curved surface structure.

[0027] Furthermore, the central region of the top surface of the light-transmitting substrate is recessed or protruded in a direction away from the gallium oxide layer, which can be considered as an inwardly concave curved surface or an upwardly convex curved surface.

[0028] For example, the top surface of the light-transmitting substrate has a diameter of 50 μm to 60 μm and a radius of curvature of 40 mm to 60 mm.

[0029] Furthermore, the high work function metal barrier layer, the gallium oxide layer, and the channel layer all have curved surface structures. For example, the curved surface structures of the high work function metal barrier layer, the gallium oxide layer, and the channel layer can be the same or similar; that is, the radii of curvature of the curved surface structures of the high work function metal barrier layer, the gallium oxide layer, and the channel layer can be the same or similar.

[0030] In one embodiment, the light-transmitting substrate is selected from a wide bandgap substrate, and the bandgap is greater than that of gallium oxide.

[0031] Furthermore, the material of the light-transmitting substrate may include, but is not limited to, sapphire, diamond, or AlN.

[0032] For example, the light-transmitting substrate is a sapphire light-transmitting substrate, and can be a c-plane or a beveled light-transmitting substrate with an off-axis angle.

[0033] In one embodiment, the bottom electrode and the passivation layer are both disposed around the barrier layer and the gallium oxide layer, and the passivation layer is distributed between the bottom electrode and the high work function metal barrier layer and the gallium oxide layer.

[0034] In one embodiment, the high work function metal constituting the high work function metal barrier layer includes, but is not limited to, one or more combinations of Ni, Pt, or Au.

[0035] In one embodiment, the thickness of the high work function metal barrier layer is greater than 0 and ≤ 5 nm to reduce the loss of ultraviolet light.

[0036] In one embodiment, the thickness of the gallium oxide layer is 150 nm to 300 nm.

[0037] In one embodiment, the second donor impurity doping concentration within the gallium oxide layer can be 1×10⁻⁶. 16 cm -3 ~1×10 17 cm -3 .

[0038] In one embodiment, the second donor impurity within the gallium oxide layer includes, but is not limited to, one or more combinations of Si, Sn, or H.

[0039] In one embodiment, the passivation layer is made of SiO2, but is not limited thereto.

[0040] In one embodiment, the bottom electrode is made of a high work function metal. The high work function metal includes, but is not limited to, one or more combinations of Ni, Pt, or Au.

[0041] In one embodiment, the thickness of the bottom electrode is 150 nm to 300 nm.

[0042] In one embodiment, the thickness of the Ge thin film is 20 nm to 50 nm.

[0043] In one embodiment, the electron concentration of the Ge thin film is 5 × 10⁻⁶. 11 cm -3 ~ 5×10 13 cm -3 Carrier mobility ≥3000 cm⁻¹ 2 / V·s.

[0044] In one embodiment, the top electrode forms an ohmic contact with the Ge thin film.

[0045] In one embodiment, the gallium oxide detector includes a solar-blind ultraviolet detector.

[0046] Some embodiments of this application also provide a method for fabricating the gallium oxide detector, including: A high work function metal barrier layer and a gallium oxide layer are sequentially formed on a light-transmitting substrate; A passivation layer is formed on the light-transmitting substrate, so that the passivation layer electrically isolates the high work function metal barrier layer and the gallium oxide layer from the bottom electrode; A bottom electrode is disposed on the light-transmitting substrate; A Ge thin film is disposed on the gallium oxide layer to form a channel layer, and the Ge thin film is electrically connected to the bottom electrode; A top electrode is disposed on the channel layer and electrically connected to the channel layer.

[0047] In one embodiment, the method further includes: A first donor impurity is doped in a designated annular region within the Ge thin film to form a heavily doped annular band, thereby constructing the channel layer; A top electrode is disposed on the channel layer, and the heavily doped ring is electrically contacted with the gallium oxide layer and the top electrode, respectively, while being electrically isolated from the bottom electrode.

[0048] In one embodiment, the method specifically includes: Provide a light-transmitting substrate with a curved top surface; A high work function metal barrier layer and a gallium oxide layer are sequentially formed on the top surface of the light-transmitting substrate, and the interface between the gallium oxide layer and the channel layer is a radially gradient depth surface.

[0049] Some embodiments of this application also provide an ultraviolet light detection method, including: detecting solar-blind ultraviolet light with the gallium oxide detector.

[0050] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application.

[0051] Example 1 Please see Figure 1 , Figure 2 A vertical Ga2O3 solar-blind ultraviolet detector, comprising: c-plane sapphire transparent substrate, the top surface of the c-plane sapphire transparent substrate is flat; A Ni barrier layer and a gallium oxide layer are stacked along the longitudinal direction of the device on the top surface of the c-plane sapphire transparent substrate. The Ni barrier layer is stacked along the longitudinal direction of the device on top of the Ni barrier layer. The orthographic projections of both the Ni barrier layer and the gallium oxide layer along the longitudinal direction of the device are circular. The diameter of both the Ni barrier layer and the gallium oxide layer is 25 μm. The thickness of the Ni barrier layer is 3 nm, and the thickness of the gallium oxide layer is 200 nm. The impurity doping concentration of the gallium oxide layer is 1 × 10⁻⁶. 16 cm -3 ; A SiO2 passivation layer is disposed on the top surface of the c-plane sapphire transparent substrate. The SiO2 passivation layer is disposed around the outside of the Ni barrier layer and the gallium oxide layer, and is in contact with the side of the Ni barrier layer and the gallium oxide layer in the lateral direction of the device. The orthographic projection of the SiO2 passivation layer along the longitudinal direction of the device is a ring, and the outer diameter of the SiO2 passivation layer is 27 μm. The Ni bottom electrode is disposed on the top surface of the c-plane sapphire transparent substrate. The Ni bottom electrode is disposed around the outside of the SiO2 passivation layer and is in contact with the side of the SiO2 passivation layer in the lateral direction of the device. The top surface of the Ni bottom electrode, the top surface of the SiO2 passivation layer and the top surface of the gallium oxide layer are located on the same plane (i.e. the interface between the gallium oxide layer and the Ge thin film). A Ge thin film is stacked longitudinally on a gallium oxide layer, a SiO2 passivation layer, and a Ni bottom electrode. The thickness of the Ge thin film is 50 nm, and the electron concentration of the Ge thin film is 1 × 10⁻⁶. 12 cm -3 The carrier mobility is 3000 cm⁻¹ 2 / V·s, The Ti / Au top electrode is disposed on and electrically connected to the Ge thin film. The orthographic projection of the Ti / Au top electrode along the longitudinal direction of the device is circular, and the diameter of the Ti / Au top electrode is 10 μm. The interface between the Ti / Au top electrode and the gallium oxide layer and the Ge thin film is coaxial. The thickness of Ti metal in the Ti / Au top electrode is 20 nm, and the thickness of Au metal is 100 nm.

[0052] Please see Figure 4 The method for preparing the gallium oxide detector in this embodiment specifically includes: 1) Provide a c-plane sapphire substrate.

[0053] 2) Preparation of Ni thin film: After organic cleaning of the c-plane sapphire substrate, Ni thin film is deposited on the top surface of the c-plane sapphire substrate by electron beam evaporation or sputtering. The thickness of the Ni thin film is controlled at 3 nm.

[0054] 3) Epitaxial gallium oxide thin film: A Si-doped gallium oxide thin film was epitaxially grown on a Ni barrier layer using MOCVD technology. The thickness of the gallium oxide thin film was 200 nm, and the donor impurity doping concentration was controlled at 1×10⁻⁶. 16 cm -3 .

[0055] 4) Etching gallium oxide and Ni films: The gallium oxide and Ni films are etched using ICP etching process to remove the portion of the outer region covering the top surface of the c-plane sapphire substrate. The remaining gallium oxide and Ni films form a circular orthographic projection along the longitudinal direction of the device, with a diameter of 25 μm.

[0056] 5) Preparation of SiO2 passivation layer: SiO2 passivation layer is deposited on the surface of the sample formed on the c-plane sapphire substrate using PECVD process. The SiO2 passivation layer covering the surface of the gallium oxide film is removed by RIE etching process. The SiO2 passivation layer is etched into a ring structure with an outer diameter of 27 μm surrounding the gallium oxide film and the Ni film. The remaining SiO2 passivation layer is in contact with the side surfaces of the gallium oxide film and the Ni film. The top surface of the SiO2 passivation layer is in the same plane as the top surface of the gallium oxide film.

[0057] 6) Fabrication of Ni bottom electrode: A Ni bottom electrode is fabricated on the top surface of the c-plane sapphire substrate and outside the SiO2 passivation layer to serve as the anode of the vertical device. The top surface of the Ni bottom electrode is in the same plane as the top surface of the SiO2 passivation layer and the top surface of the gallium oxide film, and serves as the bonding interface between the gallium oxide film and the Ge film.

[0058] 7) Preparation of Ge thin film: An unintentionally doped Ge thin film was deposited on the surface of the formed sample using electron beam evaporation. The thickness of the Ge thin film was 50 nm, and the electron concentration was 1 × 10⁻⁶. 12 cm -3 The migration rate is 3000 cm. 2 / V·s; 8) Etching the Ge thin film: The Ge thin film is etched using the ICP etching process to expose part of the Ni bottom electrode, thereby achieving electrical isolation between different devices; it is worth noting that the Ge thin film must be in contact with the Ni electrode.

[0059] 9) Preparation of Ti / Au top electrode: A circular Ti (20 nm) / Au (100 nm) bilayer metal was prepared on the surface of the Ge thin film using electron beam evaporation technology as the top electrode. The diameter of the Ti / Au top electrode was 10 μm.

[0060] It is important to note that the diameter of the Ti / Au top electrode should be 5 μm to 10 μm smaller than the diameter of the gallium oxide layer, such as... Figure 3 As shown, if the diameter of the top electrode is larger than the diameter of the gallium oxide layer, it causes the device to form a conductive channel in regions A and B and generate a large dark current, thereby reducing the photoresponse of the device.

[0061] Example 2 Please see Figure 5 , Figure 6A vertical Ga2O3 solar-blind ultraviolet detector, comprising: c-plane sapphire transparent substrate, the top surface of the c-plane sapphire transparent substrate is flat; A Ni barrier layer and a gallium oxide layer are stacked along the longitudinal direction of the device on the top surface of the c-plane sapphire transparent substrate. The Ni barrier layer is stacked along the longitudinal direction of the device on top of the Ni barrier layer. The orthographic projections of both the Ni barrier layer and the gallium oxide layer along the longitudinal direction of the device are circular. The diameter of both the Ni barrier layer and the gallium oxide layer is 25 μm. The thickness of the Ni barrier layer is 3 nm, and the thickness of the gallium oxide layer is 200 nm. The impurity doping concentration of the gallium oxide layer is 1 × 10⁻⁶. 16 cm -3 ; A SiO2 passivation layer is disposed on the top surface of the c-plane sapphire transparent substrate. The SiO2 passivation layer is disposed around the outside of the Ni barrier layer and the gallium oxide layer, and is in contact with the side of the Ni barrier layer and the gallium oxide layer in the lateral direction of the device. The orthographic projection of the SiO2 passivation layer along the longitudinal direction of the device is a ring, and the outer diameter of the SiO2 passivation layer is 27 μm. The Ni bottom electrode is disposed on the top surface of the c-plane sapphire transparent substrate. The Ni bottom electrode is disposed around the outside of the SiO2 passivation layer and is in contact with the side of the SiO2 passivation layer in the lateral direction of the device. The top surface of the Ni bottom electrode, the top surface of the SiO2 passivation layer and the top surface of the gallium oxide layer are located on the same plane (i.e. the interface between the gallium oxide layer and the Ge thin film). A Ge thin film is stacked longitudinally on a gallium oxide layer, a SiO2 passivation layer, and a Ni bottom electrode. The Ge thin film contains a heavily doped annular band formed by phosphorus impurity doping of a designated annular region within the Ge thin film. This heavily doped annular band is electrically contacted with the gallium oxide layer but electrically isolated from the bottom electrode. The thickness of the Ge thin film is 50 nm, and the electron concentration of the Ge thin film is 1 × 10⁻⁶. 12 cm -3 The carrier mobility is 3000 cm⁻¹ 2 / V·s, the phosphorus impurity concentration in the heavily doped ring band is 1×10 17 cm -3 The heavily doped ring is a circular ring structure coaxial with the gallium oxide layer and the SiO2 passivation layer, with an inner diameter of 8 μm and an outer diameter of 23 μm. The Ti / Au top electrode is disposed on a Ge thin film and electrically connected to a heavily doped ring within the Ge thin film. The orthographic projection of the Ti / Au top electrode along the longitudinal direction of the device is circular, and the diameter of the Ti / Au top electrode is 10 μm. The interface between the Ti / Au top electrode and the gallium oxide layer and the Ge thin film is coaxial. The thickness of the Ti metal in the Ti / Au top electrode is 20 nm, and the thickness of the Au metal is 100 nm.

[0062] like Figure 7 As shown, the method for fabricating the gallium oxide detector in this embodiment specifically includes: 1) Provide a c-plane sapphire substrate.

[0063] 2) Preparation of Ni thin film: After organic cleaning of the c-plane sapphire substrate, Ni thin film is deposited on the top surface of the c-plane sapphire substrate by electron beam evaporation or sputtering. The thickness of the Ni thin film is controlled at 3 nm.

[0064] 3) Epitaxial gallium oxide thin film: A Si-doped gallium oxide thin film was epitaxially grown on a Ni barrier layer using MOCVD technology. The thickness of the gallium oxide thin film was 200 nm, and the donor impurity doping concentration was controlled at 1×10⁻⁶. 16 cm -3 .

[0065] 4) Etching gallium oxide and Ni films: The gallium oxide and Ni films are etched using ICP etching process to remove the portion of the outer region covering the top surface of the c-plane sapphire substrate. The remaining gallium oxide and Ni films form a circular orthographic projection along the longitudinal direction of the device, with a diameter of 25 μm.

[0066] 5) Preparation of SiO2 passivation layer: SiO2 passivation layer is deposited on the surface of the sample formed on the c-plane sapphire substrate using PECVD process. The SiO2 passivation layer covering the surface of the gallium oxide film is removed by RIE etching process. The SiO2 passivation layer is etched into a ring structure with an outer diameter of 27 μm surrounding the gallium oxide film and the Ni film. The remaining SiO2 passivation layer is in contact with the side surfaces of the gallium oxide film and the Ni film. The top surface of the SiO2 passivation layer is in the same plane as the top surface of the gallium oxide film.

[0067] 6) Fabrication of Ni bottom electrode: A Ni bottom electrode is fabricated on the top surface of the c-plane sapphire substrate and outside the SiO2 passivation layer to serve as the anode of the vertical device. The top surface of the Ni bottom electrode is in the same plane as the top surface of the SiO2 passivation layer and the top surface of the gallium oxide film, and serves as the bonding interface between the gallium oxide film and the Ge film.

[0068] 7) Preparation of Ge thin film: An unintentionally doped Ge thin film was deposited on the surface of the formed sample using electron beam evaporation. The thickness of the Ge thin film was 50 nm, and the electron concentration was 1 × 10⁻⁶. 12 cm -3 The migration rate is 3000 cm. 2 / V·s; 8) Etching the Ge thin film: The Ge thin film is etched using the ICP etching process to expose part of the Ni bottom electrode, thereby achieving electrical isolation between different devices; it is worth noting that the Ge thin film must be in contact with the Ni electrode.

[0069] 9) Heavily doped ring zones in Ge thin films: Phosphorus impurities are implanted into designated ring regions of the Ge thin film using ion implantation technology, with a phosphorus impurity concentration of 1×10⁻⁶. 17 cm -3 This forms a heavily doped ring within the Ge thin film, coaxial with the gallium oxide thin film and the SiO2 passivation layer. The inner diameter of the heavily doped ring is 8 μm and the outer diameter is 23 μm. The heavily doped ring is in electrical contact with the gallium oxide thin film.

[0070] 10) Preparation of Ti / Au top electrode: A circular Ti (20 nm) / Au (100 nm) bilayer metal, coaxial with the heavily doped ring, is prepared on the surface of a Ge thin film using electron beam evaporation technology as the top electrode. The diameter of the Ti / Au top electrode is 10 μm, and the Ti / Au top electrode is in electrical contact with the heavily doped ring.

[0071] Example 3 Please see Figure 8 A vertical Ga2O3 solar-blind ultraviolet detector, comprising: The c-plane sapphire transparent substrate has a top surface that is a concave curved surface with a radially gradient depth. The diameter of the top surface is 55 μm and the radius of curvature is 50 mm. A Ni barrier layer and a gallium oxide layer are stacked longitudinally on the top surface of a c-plane sapphire transparent substrate. The Ni barrier layer is stacked longitudinally on top of the Ni barrier layer. Both the Ni barrier layer and the gallium oxide layer have the same curved surface structure as the top surface of the c-plane sapphire transparent substrate. The interface between the Ni barrier layer and the gallium oxide layer also has the same curved surface as the top surface of the c-plane sapphire transparent substrate, i.e., the radius of curvature of the interface is 50 mm. The orthographic projections of the Ni barrier layer and the gallium oxide layer along the longitudinal direction of the device are both circular. The diameter of both the Ni barrier layer and the gallium oxide layer is 25 μm. The thickness of the Ni barrier layer is approximately 3 nm, and the thickness of the gallium oxide layer is approximately 200 nm. The impurity doping concentration of the gallium oxide layer is 1 × 10⁻⁶. 16 cm -3 ; A SiO2 passivation layer is disposed on the top surface of the c-plane sapphire transparent substrate. The SiO2 passivation layer is disposed around the outside of the Ni barrier layer and the gallium oxide layer, and is in contact with the side of the Ni barrier layer and the gallium oxide layer in the lateral direction of the device. The orthographic projection of the SiO2 passivation layer along the longitudinal direction of the device is a ring, and the outer diameter of the SiO2 passivation layer is 27 μm. The Ni bottom electrode is disposed on the top surface of the c-plane sapphire transparent substrate. The Ni bottom electrode is disposed around the outside of the SiO2 passivation layer and contacts the side of the SiO2 passivation layer in the lateral direction of the device. The top surface of the Ni bottom electrode, the top surface of the SiO2 passivation layer and the top surface of the gallium oxide layer are located on the same curved surface (i.e. the interface between the gallium oxide layer and the Ge thin film). A Ge thin film is stacked longitudinally on a gallium oxide layer, a SiO2 passivation layer, and a Ni bottom electrode. The Ge thin film contains a heavily doped annular band formed by phosphorus impurity doping of a designated annular region within the Ge thin film. This heavily doped annular band is electrically contacted with the gallium oxide layer but electrically isolated from the bottom electrode. The Ge thin film has the same curved surface structure as the top surface of the c-plane sapphire transparent substrate. The interface between the Ge thin film and the gallium oxide layer also has the same curved surface as the top surface of the c-plane sapphire transparent substrate; that is, the radius of curvature of the interface is 50 mm. The thickness of the Ge thin film is 50 nm, and the electron concentration of the Ge thin film is 1 × 10⁻⁶. 12 cm -3 The carrier mobility is 3000 cm⁻¹ 2 / V·s, the phosphorus impurity concentration in the heavily doped ring band is 1×10 17 cm -3 The heavily doped ring is a circular ring structure coaxial with the gallium oxide layer and the SiO2 passivation layer, with an inner diameter of 8 μm and an outer diameter of 23 μm. The Ti / Au top electrode is disposed on a Ge thin film and electrically connected to a heavily doped ring within the Ge thin film. The orthographic projection of the Ti / Au top electrode along the longitudinal direction of the device is circular, and the diameter of the Ti / Au top electrode is 10 μm. The interface between the Ti / Au top electrode and the gallium oxide layer and the Ge thin film is coaxial. The thickness of the Ti metal in the Ti / Au top electrode is 20 nm, and the thickness of the Au metal is 100 nm.

[0072] Please see Figure 9 , Figure 10 The method for preparing the gallium oxide detector in this embodiment specifically includes: 1) Provide a c-plane sapphire substrate, and use etching equipment such as ICP to etch the top surface of the c-plane sapphire substrate into a radially gradient depth curved surface with a diameter of 55 μm and a radius of curvature of 50 mm.

[0073] 2) Preparation of Ni thin film: After organic cleaning of the etched c-plane sapphire substrate, Ni thin film is deposited on the top surface of the c-plane sapphire substrate by electron beam evaporation or sputtering. The thickness of the Ni thin film is controlled at 3 nm.

[0074] 3) Epitaxial gallium oxide thin film: A Si-doped gallium oxide thin film was epitaxially grown on a Ni barrier layer using MOCVD technology. The thickness of the gallium oxide thin film was 200 nm, and the donor impurity doping concentration was controlled at 1×10⁻⁶. 16 cm -3 .

[0075] 4) Etching gallium oxide and Ni films: The gallium oxide and Ni films are etched using ICP etching process to remove the portion of the outer region covering the top surface of the c-plane sapphire substrate. The remaining gallium oxide and Ni films form a circular orthographic projection along the longitudinal direction of the device, with a diameter of 25 μm.

[0076] 5) Preparation of SiO2 passivation layer: SiO2 passivation layer is deposited on the surface of the sample formed on the c-plane sapphire substrate using PECVD process. The SiO2 passivation layer covering the surface of the gallium oxide film is removed by RIE etching process. The SiO2 passivation layer is etched into a ring structure with an outer diameter of 27 μm surrounding the gallium oxide film and the Ni film. The remaining SiO2 passivation layer is in contact with the side surfaces of the gallium oxide film and the Ni film. The top surface of the SiO2 passivation layer is located in the same plane as the top surface of the gallium oxide film.

[0077] 6) Fabrication of Ni bottom electrode: A Ni bottom electrode is fabricated on the top surface of the c-plane sapphire substrate and outside the SiO2 passivation layer to serve as the anode of the vertical device. The top surface of the Ni bottom electrode is located in the same plane as the top surface of the SiO2 passivation layer and the top surface of the gallium oxide film, and serves as the bonding interface between the gallium oxide film and the Ge film.

[0078] 7) Preparation of Ge thin film: An unintentionally doped Ge thin film was deposited on the surface of the formed sample using electron beam evaporation. The thickness of the Ge thin film was 50 nm, and the electron concentration was 1 × 10⁻⁶. 12 cm -3 The migration rate is 3000 cm. 2 / V·s; 8) Etching the Ge thin film: The Ge thin film is etched using the ICP etching process to expose part of the Ni bottom electrode, thereby achieving electrical isolation between different devices; it is worth noting that the Ge thin film must be in contact with the Ni electrode.

[0079] 9) Heavily doped ring zones in Ge thin films: Phosphorus impurities are implanted into designated ring regions of the Ge thin film using ion implantation technology, with a phosphorus impurity concentration of 1×10⁻⁶. 17 cm -3 This forms a heavily doped ring within the Ge thin film, coaxial with the gallium oxide thin film and the SiO2 passivation layer. The inner diameter of the heavily doped ring is 8 μm and the outer diameter is 23 μm. The heavily doped ring is in electrical contact with the gallium oxide thin film.

[0080] 10) Preparation of Ti / Au top electrode: A circular Ti (20 nm) / Au (100 nm) bilayer metal, coaxial with the heavily doped ring, is prepared on the surface of a Ge thin film using electron beam evaporation technology as the top electrode. The diameter of the Ti / Au top electrode is 10 μm, and the Ti / Au top electrode is in electrical contact with the heavily doped ring.

[0081] Comparative Example 1 Please see Figure 15 Comparative Example 1 is a traditional vertical Ga2O3 solar-blind ultraviolet detector, including: c-plane sapphire transparent substrate, the top surface of the c-plane sapphire transparent substrate is flat; Ni bottom electrode is set on the top surface of the c-plane sapphire transparent substrate; A gallium oxide layer, stacked longitudinally along the device on the Ni bottom electrode, has a thickness of 200 nm and an impurity doping concentration of 1 × 10⁻⁶. 16 cm -3 ; The Ti / Au top electrode is disposed on the gallium oxide layer and electrically connected to the gallium oxide layer. The Ti metal thickness in the Ti / Au top electrode is 20 nm and the Au metal thickness is 100 nm.

[0082] To clearly illustrate the structure of the separate absorption and drift regions in this application, the working principle of the device will be explained below with the aid of simulation.

[0083] First, we use a planar device structure (the interface between the gallium oxide layer and the channel layer is planar) and without heavily doped rings to illustrate the role of the high work function metal barrier layer: Figure 11 The device structure of the gallium oxide detector in the embodiment of the present invention is shown in the simulation. Figure 12 Showed along Figure 11 The band structure along the dashed line A. For example... Figure 11 and Figure 12 As shown, when ultraviolet light is incident from the sapphire side, a large number of photogenerated excitons will be generated in the Ga2O3 layer. Under the influence of the built-in electric field of the Ga2O3 / Ge heterojunction, photogenerated electrons will drift into the Ge channel, while holes will move towards the surface of the Ga2O3 layer. The photogenerated electrons entering the Ge thin film will enhance the conductivity of the Ge channel, thereby enabling the detection of ultraviolet light.

[0084] The Ni barrier layer in this application serves to alter the bending direction of the band structure in the Ga2O3 / Ge heterojunction. For example... Figure 13As shown, if the Ni metal with a high work function does not raise the energy band on the light-incident side of Ga2O3, the bending direction of the Ga2O3 / Ge heterojunction will facilitate the drift of holes into the Ge channel and form a channel current. Since the hole mobility is much lower than the electron mobility, the absence of a Ni barrier layer will lead to a significant decrease in device response speed.

[0085] To further illustrate the advantages of Ge as a conductive channel, this application uses simulation to extract the current spatial distribution contour lines in the devices of this application embodiments. For example... Figure 14 As shown, the current in the Ga2O3 vertical detector is mainly distributed in regions 1 and 2 of the Ge channel. Due to Ge's extremely high electron mobility, and the fact that photogenerated electrons mainly drift into Ge under the influence of the Ni barrier layer, an extremely high photogenerated current can be formed in the device channel, and the photogenerated electrons can be quickly collected by the electrodes, thereby achieving a high-speed and ultra-sensitive photoresponse.

[0086] from Figure 14 The total current density distribution characteristics shown indicate that the current in the device of this application embodiment is mainly concentrated in regions 1 and 2 of the Ge channel. This application embodiment designs a heavily doped annular n+ region radially near the Ga2O3 / Ge interface. By locally altering the Fermi level and space charge distribution, a "funnel / channel" is created in the potential energy landscape (band profile) at the interface, guiding or accumulating photogenerated electrons radially to the desired collection path. If an n+ ring is used: the n+ region pulls down the local conduction band of Ge, resulting in a potential step (or local conduction band dip) between the n+ region and the surrounding lightly doped Ge, thus forming an electron trap / channel, making it easier for electrons injected from Ga2O3 to enter and transport to the electrode along the annular direction.

[0087] Furthermore, due to the positional misalignment between the anode and cathode of the device, the current path is not perpendicular. Therefore, in this embodiment, a radially gradient depth surface is etched on the top surface of the sapphire substrate, which alters the distribution of the local electric field lines, causing the electric field to be "focused" from the edge to the center or from the center upwards at the Ga2O3 / Ge interface. This enhances the vertical / radial coupling field components, helping photogenerated electrons to be "pulled out" of Ga2O3 and move towards the collection electrode via the Ge channel.

[0088] This application also tested and obtained the photocurrent versus voltage curves of the gallium oxide detectors in Embodiments 1, 2, and 3 of this application, as well as the gallium oxide detector in Comparative Example 1, under the same illumination conditions. Figure 16 ), the curve of photocurrent changing with time ( Figure 17 ),Depend on Figure 16 and Figure 17It can be seen that the light response of the device in Example 3 is more obvious, while the light response of the device in Comparative Example 1 is the worst. The response speed of the device in Example 3 is faster, while the response speed of the conventional device in Comparative Example 1 is the slowest.

[0089] The gallium oxide detector provided in this application integrates a Ga2O3 thin film and a Ge thin film, and combines a high work function metal barrier layer to achieve separation of the light absorption region and the drift region. The device makes full use of the extremely high light absorption coefficient of Ga2O3 and the high-speed electron transport capability of Ge to obtain a high-speed, ultra-sensitive solar-blind ultraviolet detector.

[0090] This application provides a gallium oxide detector that overcomes the performance limitations imposed by the electrical properties of Ga2O3 by integrating Ge with high electron mobility. In traditional Ga2O3 detector structures, Ga2O3 serves not only as a light-absorbing material but also as a drift region for electrons and holes. These device structures are inherently unable to overcome the theoretical limits imposed by the electrical properties of Ga2O3. However, in the gallium oxide detector provided in this application, Ga2O3 is used solely as a light-absorbing layer, while the current is primarily distributed in the Ge channel, thereby effectively avoiding the limitations imposed by the low carrier mobility and hole self-binding effect of Ga2O3.

[0091] This application provides a gallium oxide detector that innovatively introduces a high work function metal as a barrier layer, utilizing only photogenerated electrons to form the photocurrent. The introduction of the high work function metal barrier layer alters the band structure of the Ga2O3 / Ge heterojunction, causing electrons in the light-absorbing region of Ga2O3 to drift towards the channel Ge, while holes accumulate on the surface of the Ga2O3 thin film. Based on this design, not only is the high-speed electron transport capability of Ge utilized, but the low mobility of holes is also avoided in the device's response.

[0092] The gallium oxide detector provided in this application innovatively introduces a heavily doped ring band. The near-surface heavily doped ring band introduced on the Ge side can enhance the built-in electric field at the interface, making the band bending more conducive to the injection of electrons from gallium oxide into Ge and accelerating their drift transport. At the same time, the ring distribution can also bring a slight radial potential convergence effect, making the injected electrons more efficiently converge into the electrode path, thereby improving the overall photogenerated electron collection efficiency and response speed.

[0093] In the description of the embodiments of this application, it should be understood that the terms "vertical", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of this application 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, and therefore should not be construed as a limitation of this application.

[0094] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in sequences other than those illustrated or described herein.

[0095] In the embodiments of this application, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] Furthermore, the descriptions of the above embodiments are only intended to help understand this application. For those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A gallium oxide detector, characterized in that, include: A high work function metal barrier layer, a gallium oxide layer, and a channel layer are sequentially stacked, wherein the channel layer includes a Ge thin film; The bottom electrode is electrically connected to the Ge thin film; A passivation layer is disposed between the bottom electrode and the high work function metal barrier layer and the gallium oxide layer, and electrically isolates the bottom electrode from the high work function metal barrier layer and the gallium oxide layer. The bottom electrode and the passivation layer are both disposed around the high work function metal barrier layer and the gallium oxide layer. The top electrode is electrically connected to the channel layer; Furthermore, the channel layer also includes a heavily doped ring band, which is formed by doping a designated annular region within the Ge thin film with a first donor impurity and is electrically in contact with the gallium oxide layer and the top electrode, while being electrically isolated from the bottom electrode.

2. The gallium oxide detector according to claim 1, characterized in that: The doping concentration of the first donor impurity within the heavily doped ring is 1×10⁻⁶. 17 cm -3 ~ 1×10 18 cm -3 .

3. The gallium oxide detector according to claim 2, characterized in that: The first donor impurity includes one or more combinations of phosphorus, antimony, and arsenic.

4. The gallium oxide detector according to claim 1, characterized in that: The passivation layer has a ring structure, the outer diameter of the heavily doped ring is less than the inner diameter of the passivation layer, and the inner diameter of the heavily doped ring is less than the diameter of the top electrode.

5. The gallium oxide detector according to claim 1 or 4, characterized in that: The heavily doped ring band is parallel to the central axis of the top electrode.

6. The gallium oxide detector according to claim 5, characterized in that: The heavily doped ring band is coaxially arranged with the top electrode.

7. The gallium oxide detector according to claim 1, characterized in that: The interface between the gallium oxide layer and the channel layer is a radially gradient depth surface.

8. The gallium oxide detector according to claim 1 or 7, characterized in that: The central region of the interface between the gallium oxide layer and the channel layer is recessed or protruded in a direction away from the top electrode, and the interface between the gallium oxide layer and the channel layer, the heavily doped ring, and the top electrode are coaxially arranged.

9. The gallium oxide detector according to claim 1, characterized in that, Also includes: A light-transmitting substrate, wherein the high work function metal barrier layer, the gallium oxide layer and the channel layer are sequentially disposed on the top surface of the light-transmitting substrate, and the top surface of the light-transmitting substrate is a radially gradient depth curved surface.

10. The gallium oxide detector according to claim 9, characterized in that: The central region of the top surface of the light-transmitting substrate is recessed or protruded away from the gallium oxide layer.

11. The gallium oxide detector according to claim 9 or 10, characterized in that: The top surface of the light-transmitting substrate has a diameter of 50 μm to 60 μm and a radius of curvature of 40 mm to 60 mm.

12. The gallium oxide detector according to claim 9 or 10, characterized in that: The high work function metal barrier layer, the gallium oxide layer, and the channel layer all have curved surface structures.

13. The gallium oxide detector according to claim 9 or 10, characterized in that: The light-transmitting substrate is selected from wide bandgap substrates, and the bandgap is greater than that of gallium oxide.

14. The gallium oxide detector according to claim 13, characterized in that: The material of the light-transmitting substrate includes sapphire, diamond, or AlN.

15. The gallium oxide detector according to claim 1, characterized in that: The diameter of the top electrode is smaller than the diameter of the gallium oxide layer.

16. The gallium oxide detector according to claim 1, characterized in that: The material of the high work function metal barrier layer includes Ni, Pt, or Au.

17. The gallium oxide detector according to claim 1 or 16, characterized in that: The thickness of the high work function metal barrier layer is greater than 0 and ≤ 5 nm.

18. The gallium oxide detector according to claim 1 or 15, characterized in that: The thickness of the gallium oxide layer is 150 nm to 300 nm.

19. The gallium oxide detector according to claim 1, characterized in that: The second donor impurity doping concentration within the gallium oxide layer is 1×10⁻⁶. 16 cm -3 ~ 1×10 17 cm -3 .

20. The gallium oxide detector according to claim 1 or 19, characterized in that: The second donor impurity within the gallium oxide layer includes Si, Sn, or H.

21. The gallium oxide detector according to claim 1, characterized in that: The passivation layer is made of SiO2.

22. The gallium oxide detector according to claim 1, characterized in that: The bottom electrode is made of a high work function metal.

23. The gallium oxide detector according to claim 1 or 22, characterized in that: The thickness of the bottom electrode is 150 nm to 300 nm.

24. The gallium oxide detector according to claim 1, characterized in that: The thickness of the Ge thin film is 20 nm to 50 nm.

25. The gallium oxide detector according to claim 1 or 24, characterized in that: The electron concentration of the Ge thin film is 5 × 10⁻⁶. 11 cm -3 ~ 5×10 13 cm -3 Carrier mobility ≥3000 cm⁻¹ 2 / V·s.

26. The gallium oxide detector according to claim 1, characterized in that: The top electrode forms an ohmic contact with the Ge thin film.

27. The gallium oxide detector according to claim 1, characterized in that: The gallium oxide detector includes a solar-blind ultraviolet detector.

28. A method for fabricating a gallium oxide detector as described in any one of claims 1-27, characterized in that, include: A high work function metal barrier layer and a gallium oxide layer are sequentially formed on a light-transmitting substrate; A passivation layer is formed on the light-transmitting substrate, so that the passivation layer electrically isolates the high work function metal barrier layer and the gallium oxide layer from the bottom electrode; A bottom electrode is disposed on the light-transmitting substrate, and the bottom electrode and the passivation layer are both disposed around the high work function metal barrier layer and the gallium oxide layer; A Ge thin film is disposed on the gallium oxide layer, and a first donor impurity is doped in a designated annular region within the Ge thin film to form a heavily doped annular band to form a channel layer, and the Ge thin film is electrically connected to the bottom electrode. A top electrode is disposed on the channel layer, and the heavily doped ring is electrically contacted with the gallium oxide layer and the top electrode, respectively, while being electrically isolated from the bottom electrode.

29. The preparation method according to claim 28, characterized in that, include: Provide a light-transmitting substrate with a radially gradient depth surface on the top surface; A high work function metal barrier layer and a gallium oxide layer are sequentially formed on the top surface of the light-transmitting substrate, and the interface between the gallium oxide layer and the channel layer is a radially gradient depth surface.

30. A method for ultraviolet light detection, characterized in that, include: Detecting solar-blind ultraviolet light using a gallium oxide detector according to any one of claims 1-27.

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