A bidirectional semiconductor device and a method of manufacturing the same

Abstract

The application relates to a bidirectional semiconductor device and a preparation method thereof, which comprises a functional area, a first functional structure and a second functional structure, the first functional structure comprises a first control electrode formed in a first area and a first electrode and a second electrode which are distributed in a central symmetry, the second functional structure comprises a second control electrode formed in a second area and a third electrode and a fourth electrode which are distributed in a central symmetry, an area ratio of the second area to the first area is not greater than N, N is a positive number less than 1, the first electrode and the second electrode of the first functional structure serve as main electrodes of the device, the third electrode of the second functional structure is electrically connected with one of the first electrode and the second electrode of the first functional structure, and the fourth electrode serves as an output electrode of a detection signal. The device provided by the application is small in size, can meet the detection and control requirements of various use scenarios, is high in detection precision, and is wide in application range of circuit types.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a bidirectional semiconductor device and its fabrication method. Background Technology

[0002] Bidirectional semiconductor devices have a wide range of applications. Taking bidirectional power switches (BPS) as an example, BPS is also commonly known as an AC switch or a four-quadrant switch. It is an active device that allows energy to conduct in both directions and block in both directions. It is widely used in various application scenarios such as power conversion, motor drive, power regulation and protection circuits.

[0003] In practical applications, different scenarios impose different technical requirements on the detection and control of bidirectional power devices. For example, under high-power, high-current operating conditions, it is necessary to monitor the device's on-current, junction temperature changes, or abnormal overcurrent conditions in real time to prevent device failure due to overload or thermal runaway. In high-frequency or fast-switching scenarios, it is also necessary to accurately sense the device's voltage changes, switching status, and dynamic response characteristics to ensure stable system operation. In applications with complex loads or frequently changing operating conditions, power devices are required to provide accurate status feedback to support rapid adjustment or protection actions by external control circuits. Furthermore, during the design and development phase of power devices, engineers typically need to understand the internal electric field distribution, voltage distribution, and current distribution of the device in order to optimize the device structure and layout.

[0004] Existing BPS technologies typically only include the main power device structure. See also Figure 1 , Figure 1 This is a typical circuit diagram of a conventional BPS in existing technology. A BPS consists of two MOSFETs (or IGBT10 and their respective diodes 11) connected back-to-back in series. The sources of the two MOSFETs in the BPS are connected together, their drains serve as external terminals, and their gates serve as control terminals. Since MOSFETs and IGBTs are usually arranged in a vertical structure, MOSFET (or IGBT) based BPSs are typically constructed from discrete components connected by circuitry or a PCB board.

[0005] Due to the lower power loss, faster switching capability, and horizontal structure of wide-bandgap semiconductors such as GaN, III-V devices, including GaN HEMTs (Gallium Nitride High Electron Mobility Transistors), are widely used in power conversion devices. See also Figure 2 , Figure 2This is a schematic diagram of the structural principle of BPS implemented using an independent D-mode III-V device through a common drain in the existing technology. Figure 3 This is a schematic diagram of the structural principle of BPS implemented using an independent E-mode III-V device through a common source in the existing technology.

[0006] Compared to discrete devices, monolithic devices integrate components onto a single semiconductor substrate, resulting in fewer external wirings and no need for additional interfaces. This effectively reduces chip area and lowers device fabrication costs, leading to the development of optimized monolithic power devices. Figure 2 and Figure 3 Bidirectional power devices with common-source or common-drain structures are obtained by modifying the device structure. For example, Chinese invention patent application CN 119133228 A, entitled "An N-plane enhancement-type GaN bidirectional power device and its fabrication method," discloses a GaN bidirectional power device, which includes a gate and a first drain and a second drain located on both sides of the gate. As another example, Chinese invention patent application CN119921752 A, entitled "A driver chip, a bidirectional power device, and a manufacturing method," discloses a bidirectional power device, which includes a first power terminal, a second power terminal, and a driving terminal. When the bidirectional power device is a GaN device, the two power terminals are either drains or sources, and the driving terminal is the gate.

[0007] As can be seen from the current development status of bidirectional power devices, in order to meet the needs of detection and control, it is usually necessary to add additional detection, driving, or control chips to the outside of the bidirectional power device, such as the scheme in application publication number CN119921752 A, where the driving chip and the bidirectional power device are formed on different substrates and then connected by external leads. Obtaining the operating status of the power device through external detection circuits or independent sensors often increases system complexity, cost, and response delay, and the detection accuracy is easily affected by parasitic parameters, wiring conditions, and environmental noise. Furthermore, in the design and development stages of the device, existing technologies mostly rely on simulation analysis or indirect testing methods, making it difficult to provide intuitive and real-time feedback of internal parameters in actual devices, which to some extent limits further improvement in device performance.

[0008] Therefore, how to meet the technical requirements for device operating status detection, control, and design optimization in various application scenarios without significantly sacrificing the size and performance advantages of bidirectional power devices remains an urgent technical problem to be solved in this field. Summary of the Invention

[0009] To address the technical problems existing in the prior art, this invention proposes a bidirectional semiconductor device and its fabrication method, which can not only ensure the advantages of the device in terms of size and performance, but also meet the technical requirements for device operating status detection, control and design optimization in various application scenarios.

[0010] To address the aforementioned technical problems, according to one aspect of the present invention, a bidirectional semiconductor device is provided, comprising: The functional region includes at least an epitaxial layer, wherein the epitaxial layer includes a two-dimensional carrier gas; the functional region includes an adjacent first region and a second region, wherein the area ratio of the second region to the first region is not greater than N, where N is a positive number less than 1; A first functional structure includes a first control electrode formed in the first region and a first electrode and a second electrode centrally symmetrically distributed laterally, the first electrode and the second electrode being electrically connected to a two-dimensional carrier gas; and The second functional structure includes a second control electrode formed in the second region and a third and fourth electrode that are centrally symmetrically distributed laterally, the third and fourth electrodes being electrically connected to the two-dimensional carrier gas respectively. In this configuration, the first and second electrodes of the first functional structure serve as the main electrodes of the device and are used to connect to an external circuit; the third electrode of the second functional structure is electrically connected to one of the first and second electrodes of the first functional structure; and the fourth electrode of the second functional structure serves as the output electrode for the detection signal.

[0011] Optionally, the first control pole of the first functional structure is one or two. When there are two, the two first control poles are symmetrically distributed laterally.

[0012] Optionally, when the first functional structure includes two first control electrodes, the first functional structure further includes a first common electrode.

[0013] Optionally, the second control pole of the second functional structure is one or two. When there are two, the two second control poles are symmetrically distributed laterally.

[0014] Optionally, when the second functional structure includes two second control electrodes, the second functional structure also includes a second common electrode.

[0015] Optionally, the second region includes two or more sub-regions located in different orientations of the first region, and the second functional structures formed in each sub-region may be the same or different.

[0016] Optionally, the semiconductor structure types of the first functional structure and the second functional structure are the same, and the semiconductor structure type is D-mode or E-mode.

[0017] Optionally, the second control electrode of the second functional structure is electrically connected to the first control electrode of the first functional structure through a metal interconnect structure within the dielectric; and / or, the third electrode of the second functional structure is electrically connected to one of the first electrode and the second electrode of the first functional structure through a metal interconnect structure within the dielectric.

[0018] Optionally, the first functional structure includes a plurality of parallel bidirectional cells formed in the first region, wherein each cell shares a cell electrode with its neighboring cells, and the second functional structure includes at least one bidirectional cell formed in the second region, wherein the cells in the second functional structure share a cell electrode with the cells in the adjacent first region.

[0019] Optionally, the functional area is further divided into a third region in which resistors and / or diodes are formed.

[0020] According to another aspect of the present invention, the present invention also provides a method for fabricating a bidirectional semiconductor device, the method comprising: A functional region is provided, which includes at least a channel layer, a barrier layer and a dielectric layer sequentially from bottom to top. A two-dimensional carrier gas is formed in the channel layer near the barrier layer. The functional region includes an adjacent first region and a second region, and the area ratio of the second region to the first region is not greater than N, where N is a positive number less than 1. The first functional structure and the second functional structure are respectively fabricated in the first region and the second region; The first functional structure includes a first control electrode formed in the first region and a first electrode and a second electrode that are centrally symmetrically distributed laterally, the first electrode and the second electrode being electrically connected to the two-dimensional carrier gas respectively; the second functional structure includes a second control electrode formed in the second region and a third electrode and a fourth electrode that are centrally symmetrically distributed laterally, the third electrode and the fourth electrode being electrically connected to the two-dimensional carrier gas respectively. In this configuration, the first and second electrodes of the first functional structure serve as the main electrodes of the device and are used to connect to an external circuit; the third electrode of the second functional structure is electrically connected to one of the first and second electrodes of the first functional structure; and the fourth electrode of the second functional structure serves as the output electrode for the detection signal.

[0021] The bidirectional semiconductor device provided by this invention leverages the size and performance advantages of the first functional structure as the main device while integrating a small second functional structure for detection or control. This can meet the detection and control requirements of various application scenarios of semiconductor devices, reduce the complexity of external circuits, and reduce the influence of parasitic parameters, wiring conditions, and environmental noise. Therefore, it has high detection accuracy and a wide range of applicable circuits. Attached Figure Description

[0022] The preferred embodiments of the present invention will now be described in further detail with reference to the accompanying drawings, wherein: Figure 1 This is a typical circuit schematic of a traditional BPS in the existing technology; Figure 2 This is a schematic diagram of the structural principle of BPS implemented using an independent D-mode III-V device through a common drain in the prior art; Figure 3 This is a schematic diagram of the structural principle of BPS implemented using an independent E-mode III-V device through a common source in the prior art; Figure 4 This is a flowchart of a method for fabricating a bidirectional semiconductor device according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the principle structure of a bidirectional cell embodiment in a bidirectional semiconductor device provided by the present invention; Figure 6 This is a schematic diagram of the principle structure of another bidirectional cell embodiment in a bidirectional semiconductor device provided by the present invention; Figure 7 This is a schematic diagram of the principle structure of yet another bidirectional cell embodiment in a bidirectional semiconductor device provided by the present invention; Figure 8 This is a schematic diagram of the principle structure of another bidirectional cell embodiment in the bidirectional semiconductor device provided by the present invention. Figure 9 This is a schematic diagram of the cellular level principle structure of a bidirectional semiconductor device provided in Embodiment 1 of the present invention; Figure 10 This is a schematic diagram of the electrode interconnection structure of a bidirectional semiconductor device according to Embodiment 1 of the present invention. Figure 11 yes Figure 10 A schematic diagram of the surface pads of the bidirectional semiconductor device shown. Figure 12 This is a schematic diagram of the electrical principle of a bidirectional semiconductor device according to Embodiment 1 of the present invention; Figure 13 This is a schematic diagram of the application circuit principle of the bidirectional semiconductor device according to Embodiment 1 of the present invention; Figure 14 This is a schematic diagram of the electrode interconnection structure of a bidirectional semiconductor device according to Embodiment 2 of the present invention; Figure 15 yes Figure 14 A schematic diagram of the surface pads of the bidirectional semiconductor device shown. Figure 16 This is a schematic diagram of the electrical principle of a bidirectional semiconductor device according to Embodiment 2 of the present invention; Figure 17 This is a schematic diagram of the electrode interconnection structure of a bidirectional semiconductor device according to Embodiment 3 of the present invention; Figure 18 This is a schematic diagram of the application circuit principle of the bidirectional semiconductor device according to Embodiment 3 of the present invention; Figure 19 This is a schematic diagram of the electrode interconnection structure of a bidirectional semiconductor device according to Embodiment 4 of the present invention; Figure 20 This is a schematic diagram of the structural principle of a bidirectional semiconductor device according to Embodiment 5 of the present invention; Figure 21 This is a partial schematic diagram of the second functional structure in a bidirectional semiconductor device according to an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the following detailed description, reference can be made to the accompanying drawings, which form part of this application and illustrate specific embodiments of the present application. In the drawings, similar reference numerals describe substantially similar components in different figures. Specific embodiments of the present application are described in sufficient detail below to enable those skilled in the art to implement the technical solutions of the present application. It should be understood that other embodiments may also be utilized, or structural, logical, or electrical changes may be made to the embodiments of the present application.

[0025] This invention leverages the size advantages of monolithic integrated devices to provide a bidirectional semiconductor device and its fabrication method. The second functional structure for detection is fabricated simultaneously with the first functional structure on a common substrate. This eliminates the need for additional fabrication steps, achieves bidirectional functionality, and meets various detection requirements. For details, please refer to the descriptions of the various embodiments below.

[0026] Example 1 See Figure 4 , Figure 4 This is a flowchart illustrating a method for fabricating a bidirectional semiconductor device according to an embodiment of the present invention. The method includes the following steps: Step S101: Provide functional region 100. In this embodiment, functional region 100 includes, for example, a substrate and an epitaxial layer. The substrate material is, for example, intrinsic gallium nitride (GaN) or materials such as silicon (Si), silicon carbide (SiC), or sapphire (Al2O3). When the substrate is not an intrinsic GaN substrate, a buffer layer can be further introduced. The buffer layer can be one or more of aluminum nitride (AlN), gallium nitride (GaN), aluminum gallium nitride (AlGaN), indium gallium nitride (InGaN), aluminum indium nitride (AlInN), and aluminum indium gallium nitride (AlGaInN). The buffer layer can effectively reduce the influence of differences in lattice constant and thermal expansion coefficient between the substrate and the epitaxial layer, effectively avoiding cracking in the epitaxial layer. The buffer layer is an optional structure and can also be a multilayer structure, with each layer composed of different materials. When the substrate used is silicon (Si), a nucleation layer can also be introduced between the substrate and the buffer layer to avoid the melt-back effect. When using sapphire or silicon carbide substrates, a nucleation layer can also be introduced to improve the quality of the epitaxial layer.

[0027] The epitaxial layer includes a channel layer and a barrier layer, which together form a heterojunction in which a two-dimensional carrier gas, such as a two-dimensional electron gas (2DEG), is formed. The channel layer is made of materials such as GaN, and the barrier layer is made of materials such as AlGaN. A 2DEG is formed in the region of the channel layer near the barrier layer. The materials of the channel layer and the barrier layer constituting the heterojunction can also be other III-V group semiconductor materials, such as AlN, GaN, InN, and compounds of these materials, such as AlGaN, InGaN, and AlInGaN.

[0028] Step S102: Define adjacent first region 101 and second region 102 on the functional area 100.

[0029] Step S103: Prepare a first functional structure and a second functional structure in the first region 101 and the second region 102, respectively.

[0030] The first functional structure of this invention includes multiple bidirectional cells, each bidirectional cell comprising two sets of cell electrodes arranged laterally in a centrosymmetric manner. The second functional structure includes at least one bidirectional cell, and the structure of the cell in the second functional structure is identical to that of the cell in the first functional structure. The cell electrodes are, for example, source or drain electrodes, and the control electrode is, for example, gate. The cell in this invention is the basic unit cell for realizing a bidirectional conduction or blocking semiconductor structure, and its structure is, for example, [details omitted]. Figure 5 As shown, Figure 5This is a schematic diagram of the principle structure of a bidirectional cell embodiment in a bidirectional semiconductor device provided by the present invention. The bidirectional cell in this embodiment includes a first source S1, a second source S2, a first gate G1, and a second gate G2. The first source S1 and the first gate G1 are centrally symmetrically distributed laterally with respect to the second source S2 and the second gate G2, respectively. Alternatively, the bidirectional cell structure in the present invention may be, for example,... Figure 6 As shown, Figure 6 This is a schematic diagram of the principle structure of another bidirectional cell embodiment in a bidirectional semiconductor device provided by the present invention, wherein the bidirectional cell in this embodiment includes a common drain D. Alternatively, the bidirectional cell structure in the present invention may be, for example, […]. Figure 7 As shown, Figure 7 This is a schematic diagram illustrating the principle structure of another bidirectional cell embodiment in a bidirectional semiconductor device provided by the present invention. In this embodiment, a bidirectional cell is composed of two unidirectional cells, which are isolated by a dielectric. When the bidirectional cell uses a first source S1 and a second source S2 as device electrodes, the first drain D1 and the second drain D2 of each of the two unidirectional cells are electrically connected through a metal interconnect structure (not shown in the figure) within the dielectric. The bidirectional cell in the first functional structure of this embodiment includes two control electrodes, namely a first gate G1 and a second gate G2. Cell electrodes of the same type in multiple bidirectional cells in the first functional structure are connected together to form the electrodes of the device. That is, all cells in the first region constitute the first functional structure, the first source S1 of all cells are connected together as the first source S1 of the first functional structure, the second source S2 of all cells are connected together as the second source S2 of the first functional structure, the first gate G1 of all cells are connected together as the first gate G1 of the first functional structure, and the second gate G2 of all cells are connected together as the second gate G2 of the first functional structure. In the above embodiments, the first gate G1 and the second gate G2 are below the gate dielectric layer, the semiconductor structure type of the cell is D-mode (depletion type), and the semiconductor structure type of the corresponding first functional structure is D-mode.

[0031] See Figure 8 , Figure 8 This is a schematic diagram illustrating the principle structure of another bidirectional cell embodiment in a bidirectional semiconductor device provided by the present invention. In this embodiment, the semiconductor structure type of the cell is E-mode (enhancement-mode), with a P-type GaN layer below the gate G, and the 2DEG in the heterojunction is depleted. The cell in this embodiment includes a first drain D1, a second drain D2, and a gate G. Therefore, the first drains D1 of all cells in the first region are connected together to form the first drain D1 of the first functional structure, the second drains D2 of all cells are connected together to form the second drain D2 of the first functional structure, and the gates G of all cells are connected together to form the gate G of the first functional structure.

[0032] As can be seen from the foregoing embodiments, the control poles of the first functional structure can be two, such as... Figures 5 to 7 The cell structure shown in the diagram illustrates the first gate G1 and the second gate G2, with their first source S1 and second source S2 serving as the main electrodes of the device for external connection to a circuit. The control electrode of the first functional structure can be single, such as... Figure 8 The gate G shown in the cell structure has its first drain D1 and second drain D2 as the main electrodes of the device, which are used to connect to the circuit.

[0033] The second functional structure in the second region 102 includes one or more bidirectional cells. The bidirectional cells in the second region 102 have the same semiconductor type as the bidirectional cells in the first functional structure, and the structures may be the same or different.

[0034] See Figure 9 , Figure 9 This is a schematic diagram of the cellular level principle structure of a bidirectional semiconductor device according to Embodiment 1 of the present invention. In this embodiment, multiple bidirectional cells are fabricated in the first region 101 of the functional region 100, and one bidirectional cell is fabricated in the second region 102. To distinguish the cells in different regions, the cell fabricated in the first region 101 is called a power cell, and the cell fabricated in the second region 102 is called a detection cell. However, it should be understood that the naming of the cells here is only for distinction and not for functional limitation. For example, the information provided by the cell in the second region 102 can be used for detecting the state of electric field, current, voltage, etc., inside the first region, and can also be used to detect the transmission current of the first functional structure and for control or drive. The cell fabricated in the first region 101 is as follows: Figure 9 The first power cell 201, the second power cell 202, ..., the nth power cell 20n are defined. Each power cell includes a first source S1, a second source S2, a first gate G1, and a second gate G2. The first source S1 and the second source S2 are electrically connected to the 2DEG. The first cell 201, the second cell 202, ..., the nth power cell 20n are connected in parallel to form a first functional structure. The first source S1 and the second source S2, after being connected in parallel, serve as the main electrodes of the device, used to be connected to the power circuit when an external circuit is connected. The first gate G1 and the second gate G2 serve as the control electrodes of the device, used to be connected to the control circuit when an external circuit is connected. In the first region 101, two adjacent power cells share one source. Figure 9 As shown, the first power cell 201 and the second power cell 202 share the second source S2, the second power cell 202 and the next adjacent power cell share the first source S1, and so on. Electrodes of the same type are connected by interconnecting metal and then led out to the device surface.

[0035] The detection cells prepared in the second region 102 of functional region 100 are as follows Figure 9 The detection cell 301 shares a source electrode with the adjacent nth power cell 20n, meaning the first source S1 of the nth power cell 20n is also the first detection source S1' of the first detection cell 301. The first detection source S1' and the first detection gate G1' of the detection cell 301 are centrally symmetrically distributed laterally with the second detection source S2' and the second detection gate G2'. Multiple cells can be fabricated in the second region 102, and when multiple cells are present, they are connected in parallel, with electrodes of the same type serving as electrodes for the second functional structure.

[0036] according to Figure 9 As can be seen, the first detection source S1' of the detection cell 301 is also the first source S1 of the nth power cell 20n. In this embodiment, the second detection source S2' of the second functional structure can be used as the output electrode of the current detection signal. The first detection source S1' can be used as the output electrode of the voltage detection signal.

[0037] like Figure 10 As shown, Figure 10 This is a schematic diagram of the electrode interconnection structure of a bidirectional semiconductor device according to Embodiment 1 of the present invention. In the first region 101, the first source S1 in all power cells is interconnected, the second source S2 is interconnected, the first gate G1 is interconnected, and the second gate G2 is interconnected, and then led out to the outside of the device as external electrodes. Each electrode in the detection cell is also led out to the outside of the device as an external electrode. See also... Figure 11 , Figure 11 yes Figure 10 The diagram shows a schematic of the surface pads of the bidirectional semiconductor device. The electrodes of the second functional structure all serve as external electrodes of the device, thus providing more application scenarios. From the overall structure of the bidirectional semiconductor device, in this embodiment, the first source S1 and the second source S2 of the first functional structure are respectively the first and second electrodes of the device, serving as the main electrodes. The first detection source S1' and the second detection source S2' of the second functional structure serve as the third and fourth electrodes of the device, respectively. In this embodiment, the first detection source S1' of the second functional structure is electrically connected to the first source S1 of the first functional structure, and the second detection source S2' of the second functional structure serves as the output electrode of the detection signal.

[0038] Figure 12This is a schematic diagram of the electrical principle of a bidirectional semiconductor device according to Embodiment 1 of the present invention. In this example, the first source S1 and the second source S2 of the first functional structure 20 of the bidirectional semiconductor device 1 are connected to the external main circuit. Under the action of the control signal, when the current flows from the first source S1 to the second source S2 (as shown by the blue dotted line in the figure), since the first detection source S1' is the first source S1 of the adjacent power cell and the two are at the same potential, the current also flows from the first detection source S1' through 2DEG to the second detection source S2'. Thus, the main circuit current can be detected by detecting the current of the second detection source S2'.

[0039] In this invention, the second functional structure 30 serves as a current detection unit, forming a current mirror image with the first functional structure 20. The current and resistance of the second functional structure 30 are inversely proportional to those of the first functional structure 20, as shown in equation (1-1): (1-1) Among them, I senseFET For the current of the second functional structure 30, R senseFET For the resistor of the second functional structure 30, I MainFET For the current of the first functional structure 20, R MainFET The resistor is the first functional structure 20, and n is a positive number less than 1.

[0040] Therefore, once current is detected from the second detection source S2', the current of the first functional structure 20 can be calculated according to formula (1-1).

[0041] When current flows from the second source S2 to the first source S1, since the first detection source S1' and the first source S1 are at the same potential, the voltage of the first source S1 can be detected by detecting the voltage across the first detection source S1'. The second source S2 and the second detection source S2' can be electrically connected through an external circuit, and the main circuit current can be detected by the current flowing from the second detection source S2' to the first detection source S1'.

[0042] In this embodiment, when current flows from the first source S1 to the second source S2, the voltage can be monitored through the first detection source S1', and the current can be monitored through the second detection source S2'. Figure 13 As shown, Figure 13This is a schematic diagram of the application circuit principle of a bidirectional semiconductor device according to Embodiment 1 of the present invention. In this example, the first source S1 and the second source S2 of the first functional structure 20 of the bidirectional semiconductor device 1 are connected to the main circuit 40. The first gate G1 of the first functional structure 20 is connected to the first detection gate G1' of the second functional structure 30, and the second gate G2 of the first functional structure 20 and the second detection gate G2' of the second functional structure 30 are connected to each other, and then connected to the drive control circuit 50. The first detection source S1' and the second detection source S2' of the second functional structure 30 are connected to the detection circuit 60.

[0043] In the main circuit 40, when the first source S1 is at a high potential, the second source S2 is at a low potential, and the bidirectional device is turned on under the control signal of the drive circuit 50, the current flow direction of the current I1 in the main circuit is shown by the blue dashed line in the figure. The detection circuit 60 detects the current signal from the second detection source S2' and the voltage signal from the first detection source S1', and sends the detection signals to the drive control circuit 50 so that the drive control circuit 50 can implement corresponding control based on the detection signals. For example, when the bidirectional semiconductor device 1 is connected to the main circuit 40 as a switch, when the detected current or detected voltage exceeds the threshold, the bidirectional semiconductor device 1 is turned off, and the main circuit 40 is disconnected. The detection circuit 60 is, for example, a resistor R, and may also include a signal amplifier.

[0044] In the preparation of the semiconductor devices in the foregoing embodiments, the deposition, etching of various semiconductor materials, metal deposition and etching, electrode interconnection, etc., involved in this invention are conventional process methods, which will not be described in detail here.

[0045] Example 2 See Figure 14 , Figure 14 This is a schematic diagram of the electrode interconnection structure of a bidirectional semiconductor device according to Embodiment 2 of the present invention. In this embodiment, the second region 102 includes two sub-regions located on both sides of the first region 101. A second functional structure 30 is fabricated in each of the first sub-region 1021 and the second sub-region 1022. In this embodiment, the two second functional structures 30 are the same; however, it can be understood that they can also be different. For example, they can be... Figures 5 to 7 Any structure in it.

[0046] In this embodiment, the gates of the second functional structures 30 in the two sub-regions are electrically connected to the first gate G1 in the first functional structure 20 through a metal interconnect structure within the dielectric, and are led out as the first gate G1 of the device. The other gate of the second functional structure 30 in the two sub-regions is electrically connected to the second gate G2 in the first functional structure 20 through a metal interconnect structure within the dielectric, and is led out as the second gate G2 of the device. The first detection source S1' of the second functional structure 30 in the second sub-region 1022 is electrically connected to the first source S1 in the first functional structure 20 through a metal interconnect structure within the dielectric, and is led out as the first source S1 of the device. The other second detection source S2'' of this second functional structure 30 is led out as the second detection electrode S2'' of the device. The second detection source S2' of the second functional structure 30 in the first sub-region 1021 is electrically connected to the second source S2 in the first functional structure 20 through a metal interconnect structure within the dielectric, and is led out as the second source S2 of the device. The other first detection source S1' of this second functional structure 30 is led out as the first detection electrode S1' of the device. See also... Figure 15 , Figure 15 yes Figure 14 A schematic diagram of the surface pads of the bidirectional semiconductor device is shown.

[0047] Figure 16 This is a schematic diagram of the electrical principle of a bidirectional semiconductor device according to Embodiment 2 of the present invention. In this example, the gates of the first functional structure 20 and the two second functional structures 30 of the bidirectional semiconductor device 1 are connected in parallel and jointly receive control from an external driving signal.

[0048] The first source S1 and the second source S2 are used to connect to the external main circuit, and the first detection source S1' and the second detection source S2'' are used to connect to their respective detection circuits. In this embodiment, the detection circuit is a detection resistor (R_sense). Figure 16 As shown, the first detection source S1' and the second detection source S2'' of the device are respectively connected to a detection resistor (R_sense), as shown in the figure. The first detection resistor R1 and the second detection resistor R2 are measured. The voltage drop across the resistor is measured and then processed and read by the amplifier and other circuits. According to formula (1-1), the current in the main circuit can be calculated from the mirror current flowing through the second functional structure 30, thereby realizing bidirectional current monitoring.

[0049] In this embodiment, the two second functional structures 30 are used to detect the main current flowing in different directions.

[0050] Example 3 See Figure 17 , Figure 17This is a schematic diagram of the electrode interconnection structure of a bidirectional semiconductor device according to Embodiment 3 of the present invention. In the aforementioned embodiments, the power cell in the first functional structure 20 is the same as the detection cell in the second functional structure 30; however, it is understood that the power cell and the detection cell may also be different. For example, in this Embodiment 3, the detection cell 301 in the second region 102 is a common-drain bidirectional cell, wherein the drain D is a common electrode. In this embodiment, the first detection gate G1' and the second detection gate G2' of the detection cell 301 are electrically connected to the first gate G1 and the second gate G2 in the first functional structure 20 through a metal interconnection structure in the dielectric, respectively. The first source S1' of the detection cell 301 is electrically connected to the first source S1 in the first functional structure 20. The drain D of the detection cell 301 serves as the detection electrode of the device, and the second source S2' is led out.

[0051] See Figure 18 , Figure 18 This is a schematic diagram of the application circuit principle of a bidirectional semiconductor device according to Embodiment 3 of the present invention. In this embodiment, the main electrodes of the device are the first source S1 and the second source S2 of the first functional structure 20, which are connected to the main circuit. The first gate G1 and the second gate G2 of the device are connected to the drive circuit in the drive control circuit 50. The detection electrode D is used to detect the gate midpoint voltage and is connected to the drive circuit in the drive control circuit 50 through the detection circuit 60. The second detection source S2' is used to detect the current, and therefore the second detection source S2' is connected to the overcurrent protection circuit in the drive control circuit 50. When the gate midpoint voltage received by the drive control circuit 50 from the detection circuit 60 exceeds a threshold, or the current received by the detection circuit 60 exceeds a threshold, a signal is sent to the drive circuit. The drive signal sent by the drive circuit to the first gate G1 and the second gate G2 of the device cuts off the first functional structure 20, thereby disconnecting the main circuit.

[0052] The first functional structure 20 and the second functional structure 30 in the foregoing embodiments have the same semiconductor structure type, both being D-mode. However, the semiconductor device provided by the present invention can also be E-mode, as shown in Embodiment 4.

[0053] Example 4 See Figure 19 , Figure 19This is a schematic diagram of the electrode interconnection structure of a bidirectional semiconductor device according to Embodiment 4 of the present invention. The bidirectional semiconductor device in this embodiment 4 is a bidirectional single-gate E-Mode type. Each power cell in the first region 101 includes a first drain D1, a second drain D2, and a gate G, with adjacent power cells sharing a single drain. The detection cells in the second region 102 are common-source bidirectional cells, including a first detection drain D1', a second detection drain D2', a source S, a first detection gate G1', and a second detection gate G2'.

[0054] The electrode connection of the first functional structure 20 and the second functional structure 30 can also be in various ways, which will not be elaborated here.

[0055] In the above embodiments, the second functional structure 30 is exemplified by a single cell. However, it can be understood that multiple cells can also be fabricated in the second region 102. In this invention, the device area occupied by the second functional structure 30 is not greater than the device area occupied by the first functional structure 20, that is, the ratio of their areas N is less than 1, i.e., N < 1. In a preferred embodiment, N is 1 / 4, meaning the area ratio of the first functional structure 20 and the second functional structure 30 is greater than 4. This ensures that the device meets the high power requirements while also providing a unit with detection functionality.

[0056] Example 5 See Figure 20 , Figure 20 This is a schematic diagram illustrating the structural principle of a bidirectional semiconductor device according to Embodiment 5 of the present invention. In this embodiment, the functional region 100 is further divided into a third region 103, in which a resistor R is fabricated. The third region 103 is a region in the functional region 100 that is parallel to the first region 101 and the second region 102. However, it is understood that the second region 103 can also be a region in any semiconductor layer above the first region 101 or the second region 102, such as a region in a dielectric layer.

[0057] In this embodiment, when fabricating the source of the cell, the third region 103 is etched simultaneously with the source contact hole until it reaches below the 2DEG, in order to eliminate the 2DEG in the third region 103. While depositing or patterning metal to fabricate the source or gate, a resistor R is formed in the third region 103. During the metal interconnect stage, one end of the resistor R is electrically connected to the second detection source S2' in the second functional structure through the metal interconnect structure within the dielectric, and the other end is led out to the surface as the device's detection electrode S2'. That is, a resistor is connected in series between the second detection source S2' in the second functional structure and the external terminal. The resistance value is set to an appropriate value, so that the current signal output by the device has a corresponding relationship with the circuit signal in the main circuit, saving external circuitry, reducing packaging costs, and improving the accuracy and matching degree of the current mirror.

[0058] Similarly, a diode can also be fabricated at the resistor location in this embodiment, see [link to documentation]. Figure 21 , Figure 21 This is a partial schematic diagram of the second functional structure in a bidirectional semiconductor device according to an embodiment of the present invention. In this embodiment, the third region 103 is insulated from the second region 102 and the first region 101. Two electrodes, DR1 and DR2, are fabricated in the third region 103. Electrode DR1 serves as the diode anode and is connected to the 2DEG Schottky diode, while electrode DR2 serves as the diode cathode and is connected to the 2DEG ohmically, thereby enabling unidirectional current transfer between the diode anode DR1 and the diode cathode DR2 via the 2DEG. In this embodiment, the diode anode DR1 and the second detection source S' are electrically connected in the dielectric layer through a metal interconnect structure, and the diode cathode DR2 is led out to the outside of the device as an external electrode. The diode in this example can serve as a supplementary structure to the second functional structure for monitoring the forward temperature-dependent characteristics of the heterojunction.

[0059] Furthermore, the bidirectional semiconductor device of the present invention may also include a capacitor. Two metal layers spaced a certain distance apart are fabricated at any suitable location in the dielectric layer to form a capacitor of a certain capacitance, which is used to test the reliability of the plastic-encapsulated device after packaging. For example, moisture in the packaged device may change the local dielectric constant. By detecting the change in capacitance, the change in the dielectric constant of the device can be detected. Moreover, the capacitor can store energy released bidirectionally, thereby reducing the impact of unreleased energy on switching speed and reliability.

[0060] This invention, while maintaining the size and performance advantages of the primary functional structure as the main device in a bidirectional semiconductor device, integrates a small secondary functional structure for detection or control. This allows it to meet the detection and control needs of various application scenarios of semiconductor devices, reducing external circuit complexity and minimizing the impact of parasitic parameters, wiring conditions, and environmental noise. Consequently, it achieves high detection accuracy, a wide range of applicable circuits, and timely feedback / adjustment of the main device's operating status. Furthermore, in the initial device design phase, the secondary functional structure allows for understanding the distribution of internal electric fields, voltages, and currents, enabling optimization of the device layout and ultimately achieving better performance.

[0061] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes and modifications without departing from the scope of the invention. Therefore, all equivalent technical solutions should also fall within the scope of the invention.

Claims

1. A bidirectional semiconductor device, characterized in that, include: The functional region includes at least an epitaxial layer, wherein the epitaxial layer includes a two-dimensional carrier gas; the functional region includes an adjacent first region and a second region, wherein the area ratio of the second region to the first region is not greater than N, where N is a positive number less than 1; The first functional structure includes a first control electrode formed in the first region and a first electrode and a second electrode that are centrally symmetrically distributed laterally, wherein the first electrode and the second electrode are electrically connected to a two-dimensional carrier gas. as well as The second functional structure includes a second control electrode formed in the second region and a third and fourth electrode that are centrally symmetrically distributed laterally, the third and fourth electrodes being electrically connected to the two-dimensional carrier gas respectively. In this configuration, the first and second electrodes of the first functional structure serve as the main electrodes of the device and are used to connect to an external circuit; the third electrode of the second functional structure is electrically connected to one of the first and second electrodes of the first functional structure; and the fourth electrode of the second functional structure serves as the output electrode for the detection signal.

2. The bidirectional semiconductor device according to claim 1, characterized in that, The first control pole of the first functional structure is one or two. When there are two, the two first control poles are symmetrically distributed laterally.

3. The bidirectional semiconductor device according to claim 2, characterized in that, When the first functional structure includes two first control electrodes, the first functional structure also includes a first common electrode.

4. The bidirectional semiconductor device according to claim 1, characterized in that, The second control pole of the second functional structure is one or two. When there are two, the two second control poles are symmetrically distributed laterally.

5. The bidirectional semiconductor device according to claim 4, characterized in that, When the second functional structure includes two second control electrodes, the second functional structure also includes a second common electrode.

6. The bidirectional semiconductor device according to any one of claims 1-5, characterized in that, The second region includes two or more sub-regions located in different orientations of the first region, and the second functional structures formed within each sub-region may be the same or different.

7. The bidirectional semiconductor device according to claim 6, characterized in that, The first and second functional structures have the same semiconductor structure type, which is either D-mode or E-mode.

8. The bidirectional semiconductor device according to claim 1, characterized in that, The second control electrode of the second functional structure is electrically connected to the first control electrode of the first functional structure through a metal interconnect structure within the dielectric; and / or, the third electrode of the second functional structure is electrically connected to one of the first electrode and the second electrode of the first functional structure through a metal interconnect structure within the dielectric.

9. The bidirectional semiconductor device according to claim 1, characterized in that, The first functional structure includes a plurality of parallel bidirectional cells formed in the first region, wherein each cell shares a cell electrode with its neighboring cells. The second functional structure includes at least one bidirectional cell formed in the second region, wherein the cells in the second functional structure share a cell electrode with the cells in the adjacent first region.

10. The bidirectional semiconductor device according to claim 1, characterized in that, The functional area is further divided into a third region, in which resistors and / or diodes are formed.

11. A method for fabricating a bidirectional semiconductor device, characterized in that, The method includes: A functional region is provided, which includes at least a channel layer, a barrier layer and a dielectric layer sequentially from bottom to top. A two-dimensional carrier gas is formed in the channel layer near the barrier layer. The functional region includes an adjacent first region and a second region, and the area ratio of the second region to the first region is not greater than N, where N is a positive number less than 1. The first functional structure and the second functional structure are respectively fabricated in the first region and the second region; The first functional structure includes a first control electrode formed in the first region and a first electrode and a second electrode that are centrally symmetrically distributed laterally, the first electrode and the second electrode being electrically connected to the two-dimensional carrier gas respectively; the second functional structure includes a second control electrode formed in the second region and a third electrode and a fourth electrode that are centrally symmetrically distributed laterally, the third electrode and the fourth electrode being electrically connected to the two-dimensional carrier gas respectively. In this configuration, the first and second electrodes of the first functional structure serve as the main electrodes of the device and are used to connect to an external circuit; the third electrode of the second functional structure is electrically connected to one of the first and second electrodes of the first functional structure; and the fourth electrode of the second functional structure serves as the output electrode for the detection signal.

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