Optically controlled diamond bidirectional switch and preparation method thereof
By integrating a photodetector module and a bidirectional switch module on a diamond substrate and directly connecting them using an electrical connection structure, the problems of high system complexity and poor reliability in the prior art are solved, and a highly efficient and compact light-controlled switch design is realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI UNIV
- Filing Date
- 2026-05-11
- Publication Date
- 2026-06-05
AI Technical Summary
Existing diamond photodetectors and bidirectional switching devices are usually designed separately, resulting in high system complexity, strong dependence on external circuits, and poor reliability in harsh environments.
A photodetector module and a bidirectional switch module are integrated on the same diamond substrate and directly connected by an electrical connection structure. At least two independent gate structures are used to regulate the two-dimensional hole gas conductive channel to achieve the light-controlled switch function.
It reduces external connections and packaging complexity, lowers parasitic inductance and capacitance, enhances system reliability in harsh environments, and achieves high efficiency and compact structure for light-controlled switching.
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Figure CN122161187A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of semiconductor devices, and in particular to a light-controlled diamond bidirectional switch and its fabrication method. Background Technology
[0002] Diamond possesses a wide bandgap, high breakdown field strength, high thermal conductivity, and good radiation resistance, making it a promising candidate for applications in deep ultraviolet detection, high-temperature electronic devices, and power switches. In particular, hydrogen-terminated diamond surfaces can form two-dimensional hole-gas conductive channels, providing a foundation for the fabrication of diamond photodetectors and diamond field-effect switching devices.
[0003] In existing technologies, diamond photodetectors and diamond bidirectional switching devices are typically designed, fabricated, and packaged as two independent devices. To achieve light-controlled switching functionality, the discrete photodetectors and bidirectional switching devices must be connected via external circuitry. The photodetector generates an electrical signal upon receiving light, which is then used by an external gate control circuit to drive the gate of the switching device. This discrete approach results in high system complexity, requiring additional photoelectric conversion circuitry and gate driving circuitry. Furthermore, the discrete packaging introduces significant parasitic inductance and capacitance. Additionally, the increased number of external connection points reduces the system's reliability in harsh environments. Summary of the Invention
[0004] The purpose of this invention is to provide a light-controlled diamond bidirectional switch and its preparation method, so as to integrate photoelectric detection function and bidirectional switching function on the same diamond material platform, reduce external circuit dependence, and improve system integration and response performance.
[0005] To address the above problems, this invention provides a light-controlled diamond bidirectional switch and its preparation method.
[0006] The light-controlled diamond bidirectional switch of the present invention includes: Diamond substrate; A hydrogen terminal surface, formed on the diamond substrate, is used to provide a two-dimensional hole gas conductive channel, having a first region and a second region; A photoelectric detection module and a bidirectional switch module are both formed on the surface of the hydrogen terminal and are isolated from each other; the photoelectric detection module is located in a first region of the surface of the hydrogen terminal, and the bidirectional switch module is located in a second region of the surface of the hydrogen terminal; The bidirectional switching module is disposed in a second region on the surface of the hydrogen terminal, including a first main electrode, a second main electrode, a first dielectric layer, at least two gates, and a second dielectric layer; the first dielectric layer covers a portion of the first main electrode, the second main electrode, and the portion of the surface of the hydrogen terminal located between the first main electrode and the second main electrode; the at least two gates are disposed on the first dielectric layer; the second dielectric layer covers the first dielectric layer and the at least two gates; An electrical connection structure connects the output terminal of the photoelectric detection module to the at least two gates of the bidirectional switch module.
[0007] Furthermore, there are two gates, namely a first gate and a second gate, which are arranged at intervals.
[0008] Furthermore, the photoelectric detection module includes a first photoelectric detection unit and a second photoelectric detection unit that are isolated from each other; the first photoelectric detection unit includes a first electrode electrically connected to the first gate and a second electrode electrically connected to the first main electrode; the second photoelectric detection unit includes a third electrode electrically connected to the second gate and a fourth electrode electrically connected to the second main electrode.
[0009] Furthermore, the first main electrode and the second main electrode are symmetrically distributed on both sides of the first gate and the second gate.
[0010] Furthermore, an isolation structure is provided between the first region and the second region to achieve isolation.
[0011] Furthermore, the bidirectional switching module also includes a metal field plate layer, which covers a portion of the first main electrode and the second main electrode as well as the second dielectric layer, and the metal field plate layer is electrically connected to the first main electrode and the second main electrode.
[0012] Furthermore, it also includes vias that penetrate the metal field plate layer and the second dielectric layer to expose a portion of the at least two gates, so that the electrical connection structure contacts the at least two gates.
[0013] Furthermore, the metal field plate layer is made of gold, aluminum, or titanium.
[0014] Furthermore, the material of the first dielectric layer and / or the second dielectric layer is one of aluminum oxide, hafnium dioxide, silicon dioxide, or silicon nitride.
[0015] This invention also provides a method for preparing a light-controlled diamond bidirectional switch, comprising: A hydrogen plasma treatment is performed on a diamond substrate to form a hydrogen-terminated surface; An isolation structure is set on the surface of the hydrogen terminal to divide the first region and the second region; Metal is deposited on the surface of the hydrogen terminal to form a photodetector module in a first region and a first main electrode and a second main electrode of a bidirectional switching module in a second region. A first dielectric layer is deposited on the surface of the hydrogen terminal, and the first dielectric layer in the second region is etched away. At least two independent gate electrodes are formed on the portion between the first main electrode and the second main electrode of the first dielectric layer; A second dielectric layer is deposited on the surface of the hydrogen terminal to cover the first dielectric layer and the gate, and the second dielectric layer in the second region is etched away. Selective etching is performed on the first dielectric layer and the second dielectric layer to expose a portion of the first main electrode and a portion of the second main electrode; Metal is deposited on the second dielectric layer and the exposed source electrode to form a metal field plate layer with lead-out holes; Selective etching is performed on the second dielectric layer to form a via that exposes the gate. An electrical connection structure is formed to connect the output terminal of the photoelectric detection module to the gate.
[0016] Compared with the prior art, the present invention has at least the following beneficial effects: The optically controlled diamond bidirectional switch of this invention integrates a photodetector module and a bidirectional switch module on the same diamond substrate and directly connects them using an electrical connection structure, effectively solving the problems of high system complexity and high dependence on external circuits caused by traditional discrete solutions. The bidirectional switch module employs at least two independent gate structures, enabling the regulation of a two-dimensional hole gas conductive channel, thereby achieving electrical control over the on and off states of the bidirectional switch. The first and second main electrodes are spaced apart on the hydrogen terminal surface and cooperate with the at least two gates, giving the device bidirectional conduction and bidirectional blocking characteristics. The integrated design of the optically controlled diamond bidirectional switch of this invention reduces external connections and packaging complexity, and lowers parasitic inductance and capacitance. Furthermore, the direct internal connection reduces external connection points, enhances the reliability of the system in harsh environments, and achieves high efficiency, compact structure, and stable operation of the optically controlled switch function. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of one embodiment of the optically controlled diamond bidirectional switch of the present invention; Figure 2 This is a schematic diagram of the structure of one embodiment of the bidirectional switching module of the optically controlled diamond bidirectional switch of the present invention; Figure 3This is a schematic diagram of the structure of forming a hydrogen terminal surface on a diamond substrate in the method for preparing the optically controlled diamond bidirectional switch of the present invention. Figure 4 This is a schematic diagram of the method for fabricating the optically controlled diamond bidirectional switch of the present invention, showing the formation of an isolation structure on a diamond substrate; Figure 5 This is a schematic diagram of the structure of the optically controlled diamond bidirectional switch fabrication method of the present invention, which forms a photoelectric detection module, a first main electrode, and a second main electrode on the surface of a hydrogen terminal. Figure 6 This is a schematic diagram of the structure of the first dielectric layer formed on the surface of the hydrogen terminal in the method for preparing the optically controlled diamond bidirectional switch of the present invention; Figure 7 This is a schematic diagram of the structure of the optically controlled diamond bidirectional switch fabrication method of the present invention, which forms a first gate and a second gate on a first dielectric layer. Figure 8 This is a schematic diagram of the structure of forming a second dielectric layer on a first dielectric layer in the fabrication method of the optically controlled diamond bidirectional switch of the present invention; Figure 9 This is a schematic diagram of the selective etching of the first dielectric layer and the second dielectric layer in the fabrication method of the optically controlled diamond bidirectional switch of the present invention. Figure 10 This is a schematic diagram illustrating the structure of the optically controlled diamond bidirectional switch fabrication method of the present invention, which forms a metal field plate layer and its lead-out holes on the second dielectric layer. Figure 11 This is a schematic diagram illustrating the method for fabricating the optically controlled diamond bidirectional switch of the present invention, which involves forming an outlet hole on the second dielectric layer. Figure 12 This is a test diagram of the current-voltage curve of the photoelectric detection module of the optically controlled diamond bidirectional switch of the present invention. Figure 13 This is a test diagram of the current-voltage curve of the optically controlled diamond bidirectional switch of the present invention; Figure 14 This is a comparison of the current and voltage curves of the optically controlled diamond bidirectional switch of the present invention under no light and with light.
[0018] Figure label: 10. Diamond substrate; 20. Hydrogen terminal surface; 31. First main electrode; 32. Second main electrode; 33. First dielectric layer; 34. First gate electrode; 35. Second gate electrode; 36. Second dielectric layer; 37. Through-hole; 38. Metal field plate layer; 41. Electrical connection structure; 42. First electrode; 43. Second electrode; 44. Third electrode; 45. Fourth electrode; 46. Isolation structure. Detailed Implementation
[0019] The optically controlled diamond bidirectional switch and its preparation method of the present invention will be described below with reference to schematic diagrams, which illustrate preferred embodiments of the present invention. It should be understood that those skilled in the art can modify the present invention described herein while still achieving its advantageous effects. Therefore, the following description should be understood as being of broad knowledge to those skilled in the art and is not intended to limit the present invention. Based on the teachings of this specification, those skilled in the art can form new technical solutions through cross-combination of different embodiments without creating technical contradictions; such modifications should all be considered to fall within the protection scope of the present invention.
[0020] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention.
[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0022] In this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. Furthermore, the term "electrical connection" can be a direct electrical connection or an indirect electrical connection through an intermediate medium.
[0023] The invention is described more specifically by way of example in the following paragraphs with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.
[0024] The following is in conjunction with the instruction manual appendix. Figure 1 To be continued Figure 14 The present invention describes the optically controlled diamond bidirectional switch and its preparation method.
[0025] This invention proposes a photoelectric control diamond bidirectional switch, which integrates photodetection and bidirectional switching functions on the same diamond substrate 10, and uses an electrical connection structure 41 to achieve direct connection between the output terminal of the photodetection module and the gate of the bidirectional switch module.
[0026] In some of these embodiments, such as Figure 1 As shown, the optically controlled diamond bidirectional switch includes: Diamond substrate 10; Hydrogen terminal surface 20, formed on the diamond substrate 10, is used to provide a two-dimensional hole gas conductive channel, having a first region and a second region; The photoelectric detection module and the bidirectional switch module are both formed on the hydrogen terminal surface 20 and are isolated from each other; the photoelectric detection module is located in the first region of the hydrogen terminal surface 20, and the bidirectional switch module is located in the second region of the hydrogen terminal surface 20. like Figure 2 As shown, the bidirectional switching module is disposed in the second region of the hydrogen terminal surface 20, including a first main electrode 31, a second main electrode 32, a first dielectric layer 33, at least two gate electrodes, and a second dielectric layer 36; the first dielectric layer 33 covers a portion of the first main electrode 31, the second main electrode 32, and the portion of the hydrogen terminal surface 20 located between the first main electrode 31 and the second main electrode 32; the at least two gate electrodes are disposed on the first dielectric layer 33; the second dielectric layer 36 covers the first dielectric layer 33 and the at least two gate electrodes; Electrical connection structure 41 connects the output terminal of the photoelectric detection module to the at least two gates of the bidirectional switch module.
[0027] The optically controlled diamond bidirectional switch is based on a diamond substrate 10, which can be made of single-crystal or polycrystalline diamond material, and its thickness can be selected according to specific application requirements.
[0028] The hydrogen terminal surface 20 can be obtained by exposing the diamond substrate 10 to a hydrogen plasma environment, thereby inducing the formation of two-dimensional hole gas conductive channels on the surface. The hydrogen terminal surface 20 is divided into a first region and a second region to accommodate different functional modules.
[0029] Both the photodetector module and the bidirectional switch module are formed on the hydrogen terminal surface 20 and are isolated from each other. The photodetector module is arranged in a first region of the hydrogen terminal surface 20, while the bidirectional switch module is arranged in a second region of the hydrogen terminal surface 20. This arrangement ensures the physical separation of the two modules and avoids unnecessary mutual interference. For example, physical boundaries can be formed through oxygen plasma treatment, ultraviolet ozone treatment, mesa etching, or ion implantation to achieve regional isolation.
[0030] A bidirectional switching module is disposed in the second region of the hydrogen terminal surface 20, and its core components include a first main electrode 31, a second main electrode 32, a first dielectric layer 33, at least two gates, and a second dielectric layer 36. These components work together to achieve bidirectional current control. For example, the first main electrode 31 and the second main electrode 32 may be formed by metal thin film deposition and designed to have suitable dimensions to carry the target current.
[0031] The first dielectric layer 33 is configured to cover the portion of the first main electrode 31, the second main electrode 32, and the hydrogen terminal surface 20 located between the first main electrode 31 and the second main electrode 32. This dielectric layer serves as both an electrical insulator and a gate dielectric. For example, the first dielectric layer 33 can be formed by patterning processes such as atomic layer deposition (ALD), chemical vapor deposition (CVD), or physical vapor deposition (PVD). The material of the first dielectric layer 33 can be one of alumina, hafnium dioxide, silicon dioxide, or silicon nitride.
[0032] At least two gates are disposed on the first dielectric layer 33. These gates are the core structure controlling the on and off of the bidirectional switching module. For example, a tungsten or aluminum thin film can be deposited and then etched into at least two independent gate structures using standard semiconductor processes. The number and layout of these gates can be designed according to the current carrying capacity and control requirements of the device.
[0033] The second dielectric layer 36 is configured to cover the first dielectric layer 33 and the at least two gates. The second dielectric layer 36 further provides electrical insulation protection and can serve as a passivation layer for subsequent processes. For example, the second dielectric layer 36 can be formed using similar materials and processes to the first dielectric layer 33, and its thickness can be determined based on the overall insulation requirements of the device. The material of the second dielectric layer 36 can be the same as or different from that of the first dielectric layer 33; it can be one of alumina, hafnium dioxide, silicon dioxide, or silicon nitride.
[0034] The electrical connection structure 41 connects the output terminal of the photodetector module to the at least two gates of the bidirectional switch module. The electrical connection structure 41 ensures that the electrical signal generated by the photodetector module can be directly and effectively transmitted to the gates of the bidirectional switch module, thereby realizing direct light-based control of the switch. Specifically, the electrical connection structure 41 can connect the output terminal of the photodetector module to the at least two gates of the bidirectional switch module through the lead-out hole 37 on the bidirectional switch module, realizing electrical interaction between the two. This electrical connection structure 41 can be constructed from metal wires or metal interconnect layers, formed using conventional semiconductor processes.
[0035] The optically controlled diamond bidirectional switch of this invention integrates a photodetector module and a bidirectional switch module on the same diamond substrate 10, and directly connects them using an electrical connection structure 41. This effectively solves the problems of high system complexity and high dependence on external circuits caused by traditional discrete solutions. The bidirectional switch module employs at least two independent gate structures, enabling the regulation of the two-dimensional hole gas conductive channel, thereby achieving electrical control over the on and off states of the bidirectional switch. The first main electrode 31 and the second main electrode 32 are spaced apart on the hydrogen terminal surface 20 and cooperate with the at least two gates, giving the device bidirectional conduction and bidirectional blocking characteristics. The integrated design of the optically controlled diamond bidirectional switch of this invention reduces external connections and packaging complexity, and lowers parasitic inductance and capacitance. Furthermore, the direct internal connection reduces external connection points, enhances the reliability of the system in harsh environments, and achieves high efficiency, compact structure, and stable operation of the optically controlled switch function.
[0036] In some embodiments, preferably, there are two gates, namely a first gate 34 and a second gate 35, which are arranged at intervals.
[0037] Specifically, the use of two gates can simplify the device's control circuitry and reduce manufacturing complexity, while still providing sufficient controllability. For example, the two gates can be applied with voltages independently to achieve fine-grained control of carrier concentration in different regions of the channel; or, the two gates can be designed with different geometries or sizes to suit specific control requirements.
[0038] By limiting the number of gates to two and arranging them spaced apart, the ability to coordinate the control of carrier concentration and distribution within the two-dimensional hole gas conductive channel is ensured, while effectively avoiding the parasitic effects and control complexity that may result from too many gates, thus simplifying the device structure. The dual-gate structure achieves functional decoupling of carrier behavior by introducing two independent electric field control channels into the channel region.
[0039] Furthermore, in some embodiments, the photodetector module includes a first photodetector unit and a second photodetector unit that are isolated from each other, and the isolation method between the two is the same as the isolation method between the first region and the second region; the first photodetector unit includes a first electrode 42 electrically connected to the first gate 34 and a second electrode 43 electrically connected to the first main electrode 31; the second photodetector unit includes a third electrode 44 electrically connected to the second gate 35 and a fourth electrode 45 electrically connected to the second main electrode 32.
[0040] Specifically, the first electrode 42 serves as the output terminal of the first photodetector unit and is connected to the first gate 34 of the bidirectional switching module to apply a control voltage. The second electrode 43 is electrically connected to the first main electrode 31 of the bidirectional switching module, serving as a reference potential or bias potential for the first photodetector unit. This connection method ensures that the control signal of the first gate 34 can be adjusted with reference to the first main electrode 31, thereby achieving precise control of the first gate 34.
[0041] Similarly, the third electrode 44, serving as the output terminal of the second photodetector unit, is connected to the second gate 35 of the bidirectional switching module to apply a control voltage. The fourth electrode 45 is electrically connected to the second main electrode 32 of the bidirectional switching module, serving as a reference potential or bias potential for the second photodetector unit. Through this symmetrical and independent connection, the control signal of the second gate 35 can be adjusted with reference to the second main electrode 32, thereby achieving precise control of the second gate 35.
[0042] The above technical solution enables independent optical control of the two gates in the bidirectional switching module. This independent control mechanism allows the drive signal of each gate to be precisely adjusted according to the potential of its connected main electrode, effectively solving the problem that a single photodetector module cannot provide fine and differentiated control signals. Given that the roles of the first main electrode 31 and the second main electrode 32 are interchanged during forward and reverse conduction of the bidirectional switching module, this independent control method, with each main electrode as a reference, ensures that each gate obtains optimal bias and drive in any operating mode, thereby significantly improving the switching speed of the bidirectional switching module and reducing its on-resistance.
[0043] Furthermore, in some embodiments, the first main electrode 31 and the second main electrode 32 are symmetrically distributed on both sides of the first gate 34 and the second gate 35.
[0044] Specifically, "symmetrical distribution" refers to the balanced geometric configuration of the first main electrode 31 and the second main electrode 32 in space relative to the first gate 34 and the second gate 35. More specifically, this can be understood as the centerline or edge of the first main electrode 31 and the second main electrode 32 being equidistant from the centerline or central region of the array formed by the first gate 34 and the second gate 35, thus ensuring the physical symmetry of the device structure. For example, if the first gate 34 and the second gate 35 are linearly arranged along a certain direction, the first main electrode 31 and the second main electrode 32 can be located at opposite ends of the gate pair, equidistant from the centerline of the gate pair. This symmetry ensures that the device has similar electrical characteristics under forward and reverse bias.
[0045] By symmetrically distributing the first main electrode 31 and the second main electrode 32 on both sides of the first gate 34 and the second gate 35 using the above technical solution, it is possible to effectively ensure that the bidirectional switching module has highly consistent electrical performance in both forward and reverse operation. This symmetrical structural layout helps to make the current distribution in the conductive channel more uniform when the device is turned on, avoiding overheating or performance degradation caused by local current concentration. At the same time, when the device is turned off, the symmetrical electrode distribution also facilitates the uniform distribution of the electric field in the gate region, thereby improving the breakdown voltage and reliability of the device.
[0046] Furthermore, in some embodiments, an isolation structure 46 is provided between the first region and the second region to achieve isolation.
[0047] Specifically, the isolation structure 46 refers to a structure on the hydrogen-terminated surface 20 of the diamond substrate 10 used to physically or electrically separate the first region containing the photodetector module and the second region containing the bidirectional switch module. This isolation structure 46 aims to prevent current from flowing along unwanted paths, reduce mutual interference between different functional modules, and improve the integration and reliability of the device. The isolation structure 46 can be formed through oxygen plasma treatment, ultraviolet ozone treatment, mesa etching, or ion implantation processes.
[0048] These isolation methods can effectively suppress leakage current and electrical crosstalk between the first and second regions, ensuring that the photodetector module and the bidirectional switch module can work independently and efficiently, thereby significantly improving the overall performance, stability and reliability of the optically controlled diamond bidirectional switch and reducing the power consumption of the device.
[0049] Furthermore, in some embodiments, the bidirectional switching module further includes a metal field plate layer 38, which covers a portion of the first main electrode 31 and the second main electrode 32 as well as the second dielectric layer 36, and the metal field plate layer 38 is electrically connected to the first main electrode 31 and the second main electrode 32.
[0050] Specifically, the metal field layer 38 is a conductive layer, typically composed of a metallic material, and needs to possess excellent conductivity, good thermal stability, and good compatibility with the diamond substrate and dielectric layer to isolate the direct impact of external light on the bidirectional device. Preferably, the metal field layer 38 can be made of metals such as gold, aluminum, or titanium. Its formation process typically includes metal deposition techniques such as sputtering, evaporation, or electroplating, followed by patterning processes such as photolithography and etching.
[0051] The metal field plate layer 38 covers a portion of the second dielectric layer 36 and the first main electrode 31 and the second main electrode 32. This arrangement enables the metal field plate layer 38 to establish an electrical connection with the first main electrode 31 and the second main electrode 32, while its main body is located above the second dielectric layer 36.
[0052] Electrical connection is achieved between the metal field plate layer 38 and the first main electrode 31 and the second main electrode 32. This electrical connection can be achieved by opening a lead-out hole 37 in the dielectric layer so that the field plate material can directly contact the source electrode, or by depositing the field plate material directly on the exposed part of the source electrode, ensuring that the metal field plate layer 38 and the first main electrode 31 and the second main electrode 32 are at the same potential.
[0053] Furthermore, in some embodiments, an exit hole 37 is also included, which penetrates the metal field plate layer 38 and the second dielectric layer 36 to expose a portion of the at least two gates so that the electrical connection structure 41 contacts the at least two gates.
[0054] Specifically, the lead-out hole 37 can be formed by precision processes such as photolithography and etching to ensure the accuracy of its position and size.
[0055] The size and location of the via 37 are designed to expose only a portion of the gate surface, rather than the entire gate. This partial exposure can be achieved through precise photolithographic alignment and etching depth control. For example, the lateral dimension of the via 37 can be designed to be slightly smaller than the lateral dimension of the gate, or located at a specific edge or central region of the gate. This design aims to provide sufficient contact area to achieve functionality while avoiding structural integrity issues or additional process complexity that could result from overexposure.
[0056] The lead-out via 37 provides a reliable electrical contact point for the gate, enabling it to electrically interact with the output of the photodetector module via the electrical connection structure 41. After the lead-out via 37 is formed, it is typically filled with conductive material, such as by forming a metal filler inside the via through processes like physical vapor deposition (PVD), chemical vapor deposition (CVD), or electroplating, thereby establishing a connection with the electrical connection structure 41.
[0057] Through the above technical solution, the via 37 provides a direct and reliable external connection interface for the gate, overcoming the connection obstacles caused by the cover layer. The via 37 precisely penetrates the metal field plate layer 38 and the second dielectric layer 36, creating a physical path from the electrical connection structure 41 to the gate. This ensures that the gate can be effectively electrically connected to the electrical connection structure 41, enabling the control signals generated by the photodetector module to be accurately transmitted to the gate, achieving effective control of the bidirectional switching module, while avoiding the short-circuit risk caused by the metal field plate layer 38 covering the gate. By partially exposing a region of the gate, the reliability of the electrical contact is ensured while maintaining the integrity of the device structure.
[0058] In some embodiments, the first dielectric layer 33 and / or the second dielectric layer 36 are made of one of aluminum oxide, hafnium dioxide, silicon dioxide, or silicon nitride.
[0059] This invention also provides a method for fabricating a light-controlled diamond bidirectional switch. The method for fabricating the light-controlled diamond bidirectional switch of this invention will be described below with reference to the accompanying drawings. Figure 3 To be continued Figure 12 This is a flowchart illustrating the steps of the fabrication method of the optically controlled diamond bidirectional switch of the present invention. For ease of understanding, the structures of the first region and the second region on the diamond substrate 10 are shown in the same figure. The photodetector module in the first region only shows the fabrication process of one photodetector unit, but it does not mean that only one photodetector unit can be set in the first region. When multiple photodetector units are set, adjacent photodetector units are also isolated from each other by an isolation structure 46.
[0060] In some embodiments, the method for preparing the optically controlled diamond bidirectional switch includes the following steps: Step S1: Perform hydrogen plasma treatment on the diamond substrate 10 to form a hydrogen-terminated surface 20; Step S2: An isolation structure 46 is provided on the hydrogen terminal surface 20 to divide the first region and the second region; Step S3: Deposit metal on the hydrogen terminal surface 20 to form a photodetector module in the first region and a first main electrode 31 and a second main electrode 32 of a bidirectional switching module in the second region. Step S4: Deposit a first dielectric layer 33 on the hydrogen terminal surface 20, and etch away the first dielectric layer 33 in the second region; Step S5: At least two independent gate electrodes are formed on the portion between the first main electrode 31 and the second main electrode 32 of the first dielectric layer 33; Step S6: Deposit a second dielectric layer 36 on the hydrogen terminal surface 20 to cover the first dielectric layer 33 and the gate, and etch away the second dielectric layer 36 in the second region; Step S7: Selectively etch the first dielectric layer 33 and the second dielectric layer 36 to expose part of the first main electrode 31 and part of the second main electrode 32; Step S8: Deposit metal on the second dielectric layer 36 and the exposed source to form a metal field plate layer 38 with lead-out holes 37; Step S9: Selectively etch the second dielectric layer 36 to form an exposed gate via 37; Step S10: Form an electrical connection structure 41 to connect the output terminal of the photoelectric detection module to the gate.
[0061] In step S1, as Figure 3 As shown, the diamond substrate 10 is first subjected to hydrogen plasma treatment to form a hydrogen terminal surface 20, which provides the basis for a two-dimensional hole gas conductive channel for subsequent steps, ensuring that the conductivity of the device is established.
[0062] Based on this, in step S2, as Figure 4 As shown, an isolation structure 46 is provided on the hydrogen terminal surface 20 to divide the first region and the second region, thereby preventing current from flowing in unwanted paths, reducing mutual interference between different functional modules, and improving the integration and reliability of the device. The isolation structure 46 is formed by oxygen plasma treatment, ultraviolet ozone treatment, mesa etching or ion implantation process.
[0063] In step S3, as Figure 5 As shown, metal is deposited on the surface 20 of the hydrogen terminal to form a photodetector module in the first region and a first main electrode 31 and a second main electrode 32 of a bidirectional switching module in the second region.
[0064] The photodetector module in the first region is used to receive external light signals and convert them into electrical signals. The bidirectional switch module is used to control the on / off state of the current. The photodetector module may include multiple mutually isolated photodetector units. Taking the first photodetector unit as an example, the first photodetector unit includes a first electrode 42 and a second electrode 43. The first photodetector unit can be formed by depositing a metal material on the hydrogen terminal surface 20 and patterning it. For example, a metal thin film can be deposited by evaporation or sputtering, and then the first photodetector unit can be formed by photolithography and etching processes. The first main electrode 31 and the second main electrode 32 of the bidirectional switch module in the second region can be formed in the same way as the photodetector module in the first region.
[0065] Further, in step S4, as Figure 6As shown, a first dielectric layer 33 is deposited on the hydrogen terminal surface 20, and the first dielectric layer 33 in the second region is etched away. The first dielectric layer 33 serves as an insulating layer, isolating the gate from the channel, preventing short circuits, and providing a platform for gate formation. The first dielectric layer 33 is typically formed using thin-film deposition techniques, such as atomic layer deposition (ALD), chemical vapor deposition (CVD), or physical vapor deposition (PVD). The material of the first dielectric layer 33 is preferably one of alumina, hafnium dioxide, silicon dioxide, or silicon nitride.
[0066] Further, in step S5, as Figure 7 As shown, at least two independent gate electrodes are formed on the portion between the first main electrode 31 and the second main electrode 32 of the first dielectric layer 33.
[0067] In this embodiment, there are two gates, namely a first gate 34 and a second gate 35. For example, a tungsten or aluminum thin film can be deposited and then etched into the first gate 34 and the second gate 35 by standard semiconductor processes.
[0068] Further, in step S6, as Figure 8 As shown, a second dielectric layer 36 is deposited on the hydrogen terminal surface 20, covering the first dielectric layer 33 and the gate, and the second dielectric layer 36 in the second region is etched away. The second dielectric layer 36 further provides electrical insulation protection and can serve as a passivation layer for subsequent processes. For example, the second dielectric layer 36 can be formed by processes such as atomic layer deposition (ALD), plasma-enhanced chemical vapor deposition (PECVD), or sputtering. The second dielectric layer 36 can be prepared using various insulating materials, such as alumina, hafnium dioxide, silicon dioxide, and silicon nitride.
[0069] Further, in step S7, as Figure 9 As shown, selective etching is performed on the first dielectric layer 33 and the second dielectric layer 36 to expose a portion of the first main electrode 31 and a portion of the second main electrode 32.
[0070] Further, in step S8, as Figure 10 As shown, metal is deposited on the second dielectric layer 36 and the exposed portions of the first main electrode 31 and the second main electrode 32 to form a metal field layer 38 with lead-out holes 37. The metal field layer 38 covers the second dielectric layer 36 and portions of the two first main electrodes 31 and the second main electrode 32, thereby electrically connecting the metal field layer 38 to the first main electrodes 31 and the second main electrodes 32, effectively controlling the electric field at the gate edge. The metal field layer 38 can be made of metals such as gold, aluminum, or titanium. Its formation process typically includes metal deposition techniques such as sputtering, evaporation, or electroplating, followed by patterning processes such as photolithography and etching.
[0071] Further, in step S9, as Figure 11 As shown, the second dielectric layer 36 is selectively etched to form a lead-out hole 37 that exposes the gate. The lead-out hole 37 of the metal field plate layer 38 and the lead-out hole 37 of the second dielectric layer 36 together provide a reliable electrical contact point for the gate, enabling it to interact electrically with the output terminal of the photodetector module through the electrical connection structure 41.
[0072] Finally, in step S10, an electrical connection structure 41 is formed, connecting the output terminal of the photodetector module to the gate, forming a structure of a light-controlled diamond bidirectional switch as shown below. Figure 1 As shown. The electrical connection structure 41 is composed of metal wires or metal interconnect layers and can be formed using conventional semiconductor processes. The electrical connection structure 41 ensures that the electrical signals generated by the photodetector module can be directly and effectively transmitted to the gate of the bidirectional switch module, thereby realizing direct light-based control of the switch.
[0073] Figure 12 This is a test graph showing the current-voltage curve of the photoelectric detection module of the optically controlled diamond bidirectional switch of the present invention. Figure 13 This is a test graph showing the current-voltage curve of the optically controlled diamond bidirectional switch of the present invention. Figure 14 This is a comparison of the current-voltage (IV) curves of the optically controlled diamond bidirectional switch of the present invention under no light and with light. In the absence of light, the two gates of the diamond bidirectional switch are in a floating or initial potential state, and the IV curve is a solid line. When light is applied to any photodetector unit or both photodetector units are applied simultaneously, the IV curve of the bidirectional switch unit changes to a dashed line. As can be seen from the figure, the optically controlled diamond bidirectional switch of the present invention can achieve good bidirectional switching characteristics.
[0074] In some embodiments, the method for preparing the optically controlled diamond bidirectional switch can be used to prepare the optically controlled diamond bidirectional switch in the embodiments described above.
[0075] The fabrication method of the optically controlled diamond bidirectional switch of this invention enables the integration of a photodetector module and a bidirectional switch module on the same diamond substrate, and directly connects the two using an electrical connection structure. This effectively solves the problems of high system complexity and high dependence on external circuits caused by traditional discrete solutions, reduces external connection and packaging complexity, and lowers parasitic inductance and capacitance. Furthermore, the direct internal connection reduces external connection points, enhancing the system's reliability in harsh environments.
[0076] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A light-controlled diamond bidirectional switch, characterized in that, include: Diamond substrate; A hydrogen terminal surface, formed on the diamond substrate, is used to provide a two-dimensional hole gas conductive channel, having a first region and a second region; A photoelectric detection module and a bidirectional switch module are both formed on the surface of the hydrogen terminal and are isolated from each other; the photoelectric detection module is located in a first region of the surface of the hydrogen terminal, and the bidirectional switch module is located in a second region of the surface of the hydrogen terminal; The bidirectional switching module is disposed in a second region on the surface of the hydrogen terminal, and includes a first main electrode, a second main electrode, a first dielectric layer, at least two gates, and a second dielectric layer; the first dielectric layer covers a portion of the first main electrode, the second main electrode, and the portion of the surface of the hydrogen terminal located between the first main electrode and the second main electrode; the at least two gates are disposed on the first dielectric layer; The second dielectric layer covers the first dielectric layer and the at least two gates; An electrical connection structure connects the output terminal of the photoelectric detection module to the at least two gates of the bidirectional switch module.
2. The optically controlled diamond bidirectional switch according to claim 1, characterized in that, There are two gates, namely a first gate and a second gate, which are arranged at intervals.
3. The optically controlled diamond bidirectional switch according to claim 2, characterized in that, The photoelectric detection module includes a first photoelectric detection unit and a second photoelectric detection unit that are isolated from each other; the first photoelectric detection unit includes a first electrode electrically connected to the first gate and a second electrode electrically connected to the first main electrode; the second photoelectric detection unit includes a third electrode electrically connected to the second gate and a fourth electrode electrically connected to the second main electrode.
4. The optically controlled diamond bidirectional switch according to claim 2, characterized in that, The first main electrode and the second main electrode are symmetrically distributed on both sides of the first gate and the second gate.
5. The optically controlled diamond bidirectional switch according to claim 1, characterized in that, An isolation structure is provided between the first region and the second region to achieve isolation.
6. The optically controlled diamond bidirectional switch according to claim 1, characterized in that, The bidirectional switching module further includes a metal field plate layer, which covers a portion of the first main electrode and the second main electrode as well as the second dielectric layer. The metal field plate layer is electrically connected to the first main electrode and the second main electrode.
7. The optically controlled diamond bidirectional switch according to claim 6, characterized in that, It also includes vias that penetrate the metal field plate layer and the second dielectric layer to expose a portion of the at least two gates so that the electrical connection structure contacts the at least two gates.
8. The optically controlled diamond bidirectional switch according to claim 6, characterized in that, The metal field plate layer is made of gold, aluminum, or titanium.
9. The optically controlled diamond bidirectional switch according to claim 1, characterized in that, The first dielectric layer and / or the second dielectric layer are made of one of aluminum oxide, hafnium dioxide, silicon dioxide or silicon nitride.
10. A method for preparing a light-controlled diamond bidirectional switch, characterized in that, include: A hydrogen plasma treatment is performed on a diamond substrate to form a hydrogen-terminated surface; An isolation structure is set on the surface of the hydrogen terminal to divide the first region and the second region; Metal is deposited on the surface of the hydrogen terminal to form a photodetector module in a first region and a first main electrode and a second main electrode of a bidirectional switching module in a second region. A first dielectric layer is deposited on the surface of the hydrogen terminal, and the first dielectric layer in the second region is etched away. At least two independent gate electrodes are formed on the portion between the first main electrode and the second main electrode of the first dielectric layer; A second dielectric layer is deposited on the surface of the hydrogen terminal to cover the first dielectric layer and the gate, and the second dielectric layer in the second region is etched away. Selective etching is performed on the first dielectric layer and the second dielectric layer to expose a portion of the first main electrode and a portion of the second main electrode; Metal is deposited on the second dielectric layer and the exposed source electrode to form a metal field plate layer with lead-out holes; Selective etching is performed on the second dielectric layer to form a via that exposes the gate. An electrical connection structure is formed to connect the output terminal of the photoelectric detection module to the gate.