Bidirectional switch device, electronic device and method for preparing the same

Abstract

The present application provides a bidirectional switch device, an electronic device, and a method for preparing a bidirectional switch device. The bidirectional switch device includes a barrier layer, a P-GaN layer, M first P-GaN islands, N second P-GaN islands, a first ohmic contact electrode, a second ohmic contact electrode, and a gate. The P-GaN layer, the first P-GaN island, the second P-GaN island, the first ohmic contact electrode, and the second ohmic contact electrode are all arranged on the surface of the barrier layer. The first P-GaN island and the second P-GaN island are respectively located on both sides of the P-GaN layer, and are both spaced apart from the P-GaN layer. The M first P-GaN islands are spaced apart, and the N second P-GaN islands are spaced apart; the first ohmic contact electrode is electrically connected to the first P-GaN island; the second ohmic contact electrode is electrically connected to the second P-GaN island; and the gate is arranged on the surface of the P-GaN layer. The bidirectional switch device occupies a small area and has a good application scenario.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and in particular to a bidirectional switch device, an electronic device, and a method for preparing the bidirectional switch device. Background Art

[0002] In electronic devices that support both wired charging and wireless charging, a switch device that can be turned off in both directions is needed to isolate the wired charging link from the wireless charging link. For traditional Si-based MOS (Metal-Oxide-Semiconductor Field-Effect Transistor) devices, they themselves have a unidirectional body diode. Therefore, two Si-based MOS are required to be connected in series to achieve the bidirectional shutdown function. However, using two discrete NMOS (N-Metal-Oxide-Semiconductor) devices in series will occupy a larger board area, which is not conducive to the miniaturization of electronic devices. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a bidirectional switch device, an electronic device and a method for preparing a bidirectional switch device. The bidirectional switch device occupies a small area and has a good application scenario.

[0004] The embodiment of the present application provides a bidirectional switch device, which includes an epitaxial structure, a P-GaN layer, a first P-GaN island, a second P-GaN island, a first ohmic contact electrode, a second ohmic contact electrode and a gate. The epitaxial structure includes a barrier layer. The P-GaN layer, the first P-GaN island, the second P-GaN island, the first ohmic contact electrode and the second ohmic contact electrode are all arranged on the same surface of the barrier layer, wherein along the width direction of the P-GaN layer, the first P-GaN island and the second P-GaN island are respectively located on both sides of the P-GaN layer, and are both spaced apart from the P-GaN layer, there are M first P-GaN islands and N second P-GaN islands, M≥2, N≥2, and M and N are both natural numbers, and along the length direction of the P-GaN layer, the N first P-GaN islands are spaced apart, and the N second P-GaN islands are spaced apart;

[0005] The first ohmic contact electrode is located on a side of the M first P-GaN islands away from the P-GaN layer, and is electrically connected to each of the first P-GaN islands;

[0006] The second ohmic contact electrode is located on a side of the N second P-GaN islands away from the P-GaN layer, and is electrically connected to each of the second P-GaN islands;

[0007] The gate is arranged on a surface of the P-GaN layer away from the barrier layer, and is spaced apart from the first ohmic contact electrode and the second ohmic contact electrode.

[0008] The bidirectional switch device provided in the embodiment of the present application can control the voltage between the gate and the first ohmic contact electrode or the second ohmic contact electrode to be greater than the threshold voltage of the bidirectional switch device, so that a conductive channel is formed under the gate and the bidirectional switch device is turned on. The voltage between the gate and the first ohmic contact electrode or the second ohmic contact electrode is controlled to be less than the threshold voltage of the bidirectional switch device, so that the channel under the gate is closed and the bidirectional switch device is turned off, thereby realizing the bidirectional shutoff function of the bidirectional switch device.

[0009] Compared with the currently used silicon (Si) based MOS devices, the bidirectional switch device provided in the embodiment of the present application is a high electron mobility transistor (HEMT) device based on gallium nitride (GaN). On the one hand, it does not need to use a body diode, which solves the problem that two silicon (Si) based MOS devices are required to achieve bidirectional shutdown, resulting in a large occupied area. The bidirectional switch device in the embodiment of the present application occupies a small area, which is conducive to the miniaturization of assembled electronic devices. On the other hand, the gallium nitride (GaN) material used has a higher critical electric field, a unique and excellent dynamic on-resistance, and a lower capacitance, so that the bidirectional switch device has the advantages of fast switching speed, low on-resistance and high breakdown voltage, and has good application prospects in consumer electronics, data centers, industrial control and other fields.

[0010] In addition, due to material defects or process damage, other existing gallium nitride (GaN)-based HEMT devices will have a phenomenon of reduced output current, which is the so-called "current collapse effect". The bidirectional switch device provided in the embodiment of the present application takes the first ohmic contact electrode connected to a high potential and the second ohmic contact electrode connected to a low potential as an example. When the voltage between the gate and the second ohmic contact electrode is less than the threshold voltage of the bidirectional switch device, the channel under the gate is closed and the bidirectional switch device is turned off. There is a strong electric field on the side of the gate close to the first ohmic contact electrode, and some electrons in the gate metal can be excited to become free electrons. Under the action of the electric field, the free electrons move from the gate to the first ohmic contact electrode along the surface of the barrier layer. The present application arranges a first P-GaN island on the side of the first ohmic contact electrode, and electrically connects the first ohmic contact electrode to the surface of the first P-GaN island. The first P-GaN island will form holes under the high voltage condition of the first ohmic contact electrode, and the holes of the first P-GaN island will be injected into the barrier layer in a direction perpendicular to the surface of the barrier layer. The injected holes will neutralize the electrons captured by the surface traps of the barrier layer, thereby effectively alleviating or even eliminating the "current collapse effect" of the bidirectional switching device, thereby improving the reliability of the bidirectional switching device.

[0011] In addition, when the voltage between the gate and the second ohmic contact electrode is greater than the threshold voltage of the bidirectional switch device, the bidirectional switch device is turned on, and the current can flow from the first ohmic contact electrode to the second ohmic contact electrode. Since the second ohmic contact electrode is connected to a low potential, the second P-GaN island below the second ohmic contact electrode does not form a conductive channel, and the current flowing from the first ohmic contact electrode to the second ohmic contact electrode will be separated by the second P-GaN island. The introduction of the second P-GaN island limits the flow direction of the current of the bidirectional switch device, so that the current flowing from the first ohmic contact electrode to the second ohmic contact electrode can only flow out from the channel formed between the two adjacent second P-GaN islands, so that the second ohmic contact electrode has a gathering effect on the current. At this time, the second P-GaN island has a blocking effect on the current flowing through, generates a very high impedance, reduces the current flowing through, thereby helping to reduce the power consumption of the bidirectional switch device, and thus can improve the short-circuit tolerance of the bidirectional switch device.

[0012] In a possible implementation, along the length direction of the P-GaN layer, the length of the barrier layer is W, and the total length of the M first P-GaN islands is W1. c , W1 c / W = 1% to 20%, which ensures that the width of the channel between adjacent first P-GaN islands is wide enough, and the impedance of the first P-GaN island to the current is not particularly large, which is conducive to ensuring the normal operation of the bidirectional switch device. The total length of the N second P-GaN islands is W2 c , W2 c / W=1%-20%, which ensures that the width of the channel between adjacent second P-GaN islands is wide enough, and the impedance of the second P-GaN islands to the current is not particularly large, thereby facilitating the normal operation of the bidirectional switch device.

[0013] In a possible implementation, M first P-GaN islands are evenly spaced, and the distance between two adjacent first P-GaN islands is D1; ​​N second P-GaN islands are evenly spaced, and the distance between two adjacent second P-GaN islands is D2, and D1=D2.

[0014] In a possible implementation manner, M=N, and each second P-GaN island is mirror-symmetric to a first P-GaN island with respect to the P-GaN layer.

[0015] In one possible implementation, the projection of the first ohmic contact electrode on the surface of the barrier layer at least partially covers the area between two adjacent first P-GaN islands, so that there is an area below the first ohmic contact electrode where the first P-GaN island is not provided, so that the first ohmic contact electrode can act as a field plate structure, which can attract the electric field, so that the electric field gathered in the corner of the P-GaN layer is dispersed, thereby facilitating the improvement of the breakdown voltage of the bidirectional switching device.

[0016] In one possible embodiment, the first ohmic contact electrode includes a first electrode portion and a second electrode portion, the first electrode portion is arranged on the surface of the barrier layer and is located on the side of the first P-GaN island away from the P-GaN layer, and is spaced apart from the first P-GaN island, the second electrode portion is arranged on the surface of the first electrode portion away from the barrier layer, and is connected between the first electrode portion and each first P-GaN island, and the projection of the second electrode portion on the surface of the barrier layer at least partially covers the area spaced between the first electrode portion and the first P-GaN island, and at least partially covers the area spaced between two adjacent first P-GaN islands.

[0017] In one possible embodiment, the projection of the second ohmic contact electrode on the surface of the barrier layer at least partially covers the area between two adjacent second P-GaN islands, so that there is an area below the second ohmic contact electrode where no second P-GaN island is provided, so that the second ohmic contact electrode can act as a field plate structure, which can attract the electric field and disperse the electric field gathered in the corner of the P-GaN layer, thereby facilitating the improvement of the breakdown voltage of the bidirectional switching device.

[0018] In a possible implementation manner, along the width direction of the P-GaN layer, the width of each first P-GaN island is L P1-ISO , L P1-ISO =0.1μm~0.5μm, the width of each second P-GaN island is L P2-ISO, L P2-ISO =0.1μm~0.5μm.

[0019] In one possible implementation, the width of the P-GaN layer is L P-GaN , L P-GaN =0.1μm~0.5μm.

[0020] In a possible embodiment, the bidirectional switch device further includes a first passivation layer, which is disposed on the surface of the barrier layer, connected between the first ohmic contact electrode and the second ohmic contact electrode, and covers the peripheral surface of the P-GaN layer, the peripheral surface of the first P-GaN island, and the peripheral surface of the second P-GaN island. By providing the first passivation layer, the first passivation layer can be used to reduce surface traps of the barrier layer in the bidirectional switch device on the one hand, thereby reducing the current collapse effect of the bidirectional switch device. On the other hand, the surface structure of the bidirectional switch device can also be protected from damage when the first ohmic contact electrode and the second ohmic contact electrode are prepared by an annealing step during the preparation process of the bidirectional switch device.

[0021] In a possible implementation, the bidirectional switch device further includes a second passivation layer and a first field plate, the second passivation layer is disposed on the side of the first ohmic contact electrode, the second ohmic contact electrode and the gate away from the barrier layer, and covers the first passivation layer, and the first field plate is disposed on the surface of the second passivation layer away from the barrier layer. The second passivation layer can enhance the protection of the surface of the bidirectional switch device and further reduce the impact of oxygen or water vapor in the air on the surface of the bidirectional switch device. By providing the first field plate, the breakdown voltage of the bidirectional switch device can be increased. In addition, the first field plate floats above the gate and has no electrical connection with the gate, and the potential of the first field plate and the gate can be adjusted separately.

[0022] In a possible embodiment, there are multiple first field plates, and the multiple first field plates include a first plate and a second plate. The first plate and the second plate are both arranged on the surface of the second passivation layer away from the barrier layer, and along the width direction of the P-GaN layer, the projections of the first plate and the second plate on the P-GaN layer are respectively located on opposite sides of the gate.

[0023] In a possible embodiment, the bidirectional switch device further includes a second passivation layer and a second field plate, the second passivation layer is arranged on the side of the first ohmic contact electrode, the second ohmic contact electrode and the gate away from the barrier layer, and covers the first passivation layer, and the second field plate is arranged in the second passivation layer and is electrically connected to the gate. The second passivation layer can enhance the protection of the surface of the bidirectional switch device and further reduce the impact of oxygen or water vapor in the air on the surface of the bidirectional switch device. By providing the second field plate, the breakdown voltage of the bidirectional switch device can be increased. In addition, the second field plate is electrically connected to the gate, and the second field plate and the gate can be completed at one time when the gate is prepared, and the process is relatively simple.

[0024] In one possible embodiment, there are multiple second field plates, and the multiple second field plates include a first sub-plate and a second sub-plate. The first sub-plate and the second sub-plate are both arranged in the second passivation layer. Along the width direction of the P-GaN layer, the first sub-plate and the second sub-plate are respectively located on opposite sides of the gate and are both electrically connected to the gate.

[0025] An embodiment of the present application also provides an electronic device, including a power module, a controller and at least two charging links, each charging link including a charging access terminal and a bidirectional switching device as described above, the charging access terminal is used to connect to an external power supply, the first ohmic contact electrode is electrically connected to the charging access terminal, the second ohmic contact electrode is electrically connected to the power module, and the gate is electrically connected to the controller.

[0026] In the electronic device provided in the embodiment of the present application, at least two charging links can be used to independently charge the power module. Specifically, when the electronic device uses one charging link to charge the power module, the controller controls the bidirectional switch device of the charging link to be turned on, and the bidirectional switch devices of other charging links to be turned off, so that the current can be connected to the charging link from the charging access end in the charging link where the bidirectional switch device is in the on state to charge the power module. At this time, the voltage of the power module is the same as that of the charging access end of the charging link, which is also a high voltage. Since the bidirectional switch devices in other charging links remain turned off, it can be ensured that the voltage of the charging access end of other charging links is not affected by the voltage of the charging link, thereby achieving isolation between different charging links.

[0027] In addition, when an electronic device is charged using a charging link, if an abnormality is detected in the charging link, the controller can be used to control the bidirectional switch device in the charging link to shut down to ensure that the internal components of the electronic device are not affected by the high voltage at the charging access end of the charging link.

[0028] In a possible implementation, the at least two charging links include a first charging link and a second charging link, the charging access end of the first charging link is a wireless charging access end, and the charging access end of the second charging link is a wired charging access end.

[0029] The present application also provides a method for preparing a bidirectional switch device, comprising:

[0030] providing an epitaxial structure, the epitaxial structure comprising a barrier layer;

[0031] A P-GaN material layer is prepared on the surface of the barrier layer, and the P-GaN material layer is patterned to obtain a P-GaN layer, M first P-GaN islands, and N second P-GaN islands, where M≥2, N≥2, and M and N are both natural numbers, and along the width direction of the P-GaN layer, the first P-GaN island and the second P-GaN island are respectively located on both sides of the P-GaN layer, and are both spaced apart from the P-GaN layer;

[0032] A first passivation layer is formed on the surface of the barrier layer, wherein the first passivation layer covers the peripheral surface of the P-GaN layer, the peripheral surface of the first P-GaN island, and the peripheral surface of the second P-GaN island;

[0033] The first passivation layer is etched to expose the surface of the barrier layer, and a first ohmic electrode and a second ohmic electrode are prepared on the surface of the exposed barrier layer, wherein the first ohmic electrode is located on a side of the M first P-GaN islands away from the P-GaN layer and is electrically connected to each of the first P-GaN islands, and the second ohmic contact electrode is located on a side of the N second P-GaN islands away from the P-GaN layer and is electrically connected to each of the second P-GaN islands;

[0034] The first passivation layer is etched to expose the surface of the P-GaN layer away from the barrier layer, and a gate is prepared on the surface of the P-GaN layer away from the barrier layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic diagram of the charging principle of an electronic device provided in an embodiment of the present application;

[0037] Figure 2 for Figure 1 A circuit diagram of the electronic device shown in the charging scenario;

[0038] Figure 3 for Figure 2 A schematic structural diagram of a bidirectional switch device in the electronic device in a first embodiment;

[0039] Figure 4 for Figure 3 A schematic structural diagram of the bidirectional switch device shown in FIG. 1 with the first ohmic contact electrode and the second ohmic contact electrode removed;

[0040] Figure 5 for Figure 3 A schematic diagram of the top view of the bidirectional switch device shown;

[0041] Figure 6 for Figure 5 A schematic diagram of the cross-sectional structure of the bidirectional switch device shown at AA;

[0042] Figure 7 for Figure 5 A schematic diagram of the cross-sectional structure of the bidirectional switch device shown at BB;

[0043] Figure 8 is a schematic structural diagram of a bidirectional switch device in a second embodiment;

[0044] Fig. 9 for Figure 3 A schematic diagram of the preparation process of the bidirectional switch device shown;

[0045] Fig.10 for Figure 3 A schematic diagram of some preparation steps of the structure of the bidirectional switch device shown;

[0046] Fig.11 for Figure 3 A schematic diagram of another part of the preparation steps of the structure of the bidirectional switch device shown;

[0047] Fig.12 is a schematic structural diagram of a bidirectional switch device in a third embodiment;

[0048] Fig.13 for Fig.12 A schematic diagram of the top view of the bidirectional switch device shown;

[0049] Fig.14 for Fig.12 A schematic diagram of the cross-sectional structure of the bidirectional switch device shown at AA;

[0050] Fig.15 for Fig.12 A schematic diagram of the cross-sectional structure of the bidirectional switch device shown at BB;

[0051] Fig.16 is a schematic structural diagram of a bidirectional switch device in a fourth embodiment;

[0052] Fig.17 for Fig.16 A schematic diagram of the top view of the bidirectional switch device shown;

[0053] Fig.18 for Fig.17 A schematic diagram of the cross-sectional structure of the bidirectional switch device shown at AA;

[0054] Fig.19 for Fig.17 Schematic diagram of the cross-sectional structure of the bidirectional switch device at BB. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] See also Figure 1 and Figure 2 , Figure 1 A schematic diagram of the charging principle of the electronic device 1 provided in an embodiment of the present application, Figure 2 for Figure 1 The circuit diagram of the electronic device 1 in the charging scenario is shown.

[0057] The electronic device 1 includes at least two charging links 100, a controller 300 and a power module 500. The at least two charging links 100 are isolated from each other, and the controller 300 is electrically connected to the at least two charging links 100 and is used to control each charging link 100 to be in an on state and an off state. The power module 500 is electrically connected to the at least two charging links 100 so that each charging link 100 can independently charge the power module 500. When the controller 300 controls a charging link 100 to be in an on state, the charging link 100 transmits a voltage to the power module 500 to charge the power module 500. When the controller 300 controls a charging link 100 to be in an off state, the charging link 100 stops charging the power module 500.

[0058] Specifically, each charging link 100 includes a bidirectional switch device 110 and a charging access terminal 130. Among them, the bidirectional switch device 110 includes a first connection terminal 111, a second connection terminal 113 and a third connection terminal 115. The first connection terminal 111 is electrically connected to the charging access terminal 130, the third connection terminal 115 is used to be electrically connected to the controller 300, and the second connection terminal 113 is used to be electrically connected to the power module 500. Exemplarily, the charging access terminal 130 is a wireless charging access terminal or a wired charging access terminal. Among them, the wireless charging access terminal includes but is not limited to a wireless charging chip or a wireless charging coil. The wired charging access terminal includes but is not limited to ports such as a USB (Universal Serial Bus) interface, a TYPC interface or a TYPA interface.

[0059] In this embodiment, at least two charging links 100 include a first charging link 100a and a second charging link 100b. The charging access terminal 130 of the first charging link 100a is a wired charging access terminal, and the charging access terminal 130 of the second charging link 100b is a wireless charging access terminal.

[0060] The controller 300 controls the on and off of the bidirectional switch device 110 by applying a voltage to the third connection terminal 115 of the bidirectional switch device 110. Exemplarily, the bidirectional switch device 110 has a threshold voltage (The Threshold Voltage), and when the voltage between the third connection terminal 115 and the first connection terminal 111 is higher than the threshold voltage of the bidirectional switch device 110, the bidirectional switch device 110 is turned on, so that when the voltage between the third connection terminal 115 and the first connection terminal 111 is lower than the threshold voltage of the bidirectional switch device 110, the bidirectional switch device 110 is turned off.

[0061] In this embodiment, the power module 500 includes a power management chip (Power Management Integrated Circuit, PMIC) 510, a battery 530 and a power device 550. The power management chip 510 is electrically connected to each charging link 100, and is electrically connected to the battery 530 and the power device 550. Among them, the power management chip 510 is used to convert the input voltage of the charging link 100. Specifically, the power management chip 510 includes an input terminal 511 and an output terminal 513. The input terminal 511 of the power management chip 510 is connected to the second connection terminal 113 of the bidirectional switch device 110 to realize the connection between the power management chip 510 and the bidirectional switch device 110, thereby realizing the electrical connection between the power module 500 and the charging link 100. The output terminal 513 of the power management chip 510 is electrically connected to the battery 530 and the electrical device 550 to achieve electrical connection between the power management chip 510 and the battery 530 and the electrical device 550, thereby respectively charging the battery 530 and supplying power to the electrical device 550.

[0062] In the electronic device 1 provided in the embodiment of the present application, at least two charging links 100 can be used to independently charge the power module 500. Specifically, when the electronic device 1 uses the first charging link 100a to charge the power module 500, that is, when the electronic device 1 performs wired charging, the controller 300 controls the bidirectional switch device 110 of the first charging link 100a in the electronic device 1 to turn on and the bidirectional switch device 110 of the second charging link 100b to turn off, and the current can be connected from the charging access terminal 130 of the first charging link 100a to the first charging link 100a, and enter the power management chip 510 of the power module 500. At this time, the voltage of the input terminal 511 of the power management chip 510 is the same as that of the charging access terminal 130 of the first charging link 100a, which is also high voltage. The bidirectional switch device 110 in the second charging link 100b remains turned off, which can ensure that the voltage of the charging access terminal 130 of the second charging link 100b is not affected by the voltage of the first charging link 100a, thereby isolating the second charging link 100b from the first charging link 100a.

[0063] In addition, when the electronic device 1 is charged using the second charging link 100b, that is, when the electronic device 1 is wirelessly charged, if an abnormality is detected in the second charging link 100b, the controller 300 can be used to control the bidirectional switch device 110 in the second charging link 100b to be turned off, so as to ensure that the internal components of the electronic device 1 are not affected by the high voltage of the charging access terminal 130 of the second charging link 100b.

[0064] See also Figure 3 , Figure 4 and Figure 5 , Figure 3 for Figure 2 The schematic diagram of the structure of the bidirectional switch device 110 in the electronic device 1 in the first embodiment is shown. Figure 4 for Figure 3 The schematic diagram of the structure of the bidirectional switch device 110 with the first ohmic contact electrode 50 and the second ohmic contact electrode 60 removed is shown. Figure 5 for Figure 3 The schematic diagram of the top view of the bidirectional switch device 110 is shown. Figure 5 The first P-GaN island 30 and the second P-GaN island 40 are shown using dotted lines to indicate the structure from a perspective.

[0065] For the convenience of description, we define Figure 3 The length direction of the bidirectional switch device 110 is the X-axis direction, the width direction is the Y-axis direction, and the thickness direction is the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The words "upper", "lower", etc. mentioned in the description of the bidirectional switch device 110 in the embodiment of the present application are based on the attached specification. Figure 3The description of the orientation shown uses the positive direction of the Z axis as “up” and the negative direction of the Z axis as “down”, which does not constitute a limitation on the bidirectional switch device 110 in actual application scenarios.

[0066] The width of the bidirectional switch device 110 extending along the Y-axis direction is W. The bidirectional switch device 110 includes an epitaxial structure 10, a P-GaN layer 20, a first P-GaN island 30 (see Figure 4 ), the second P-GaN island 40 (see Figure 4 ), a first ohmic contact electrode 50, a second ohmic contact electrode 60, a first passivation layer 70 and a gate 80. Among them, the materials of the P-GaN layer 20, the first P-GaN island 30 and the second P-GaN island 40 are all P-type gallium nitride (GaN). Exemplarily, P-type gallium nitride can be obtained by performing p-type doping in gallium nitride. The specific p-type doping method can adopt existing means, which will not be repeated here.

[0067] The P-GaN layer 20, the first P-GaN island 30, the second P-GaN island 40, the first ohmic contact electrode 50, the second ohmic contact electrode 60 and the first passivation layer 70 are all disposed on the same surface of the epitaxial structure 10. In the width direction of the P-GaN layer 20, the first P-GaN island 30 and the second P-GaN island 40 are respectively located on both sides of the P-GaN layer 20, and are both spaced apart from the P-GaN layer 20. The first ohmic contact electrode 50 is electrically connected to the first P-GaN island 30, and the second ohmic contact electrode 60 is electrically connected to the second P-GaN island 40. The first passivation layer 70 is disposed between the P-GaN layer 20 and the first ohmic contact electrode 50, and is disposed around the first P-GaN island 30, and is disposed between the P-GaN layer 20 and the second ohmic contact electrode 60, and is disposed around the second P-GaN island 40.

[0068] The gate 80 is disposed on the surface of the P-GaN layer 20 away from the epitaxial structure 10, and is spaced apart from the first ohmic contact electrode 50 and the second ohmic contact electrode 60. In this embodiment, the first ohmic contact electrode 50 can be used as a drain electrode, connected to a high potential, and the second ohmic contact electrode 60 can be used as a source electrode, connected to a low potential. At this time, the first ohmic contact electrode 50 can be used as the second connection terminal 113 of the bidirectional switch device 110, the second ohmic contact electrode 60 can be used as the first connection terminal 111 of the bidirectional switch device 110, and the gate 80 can be used as the third connection terminal 115 of the bidirectional switch device 110. It can be understood that in other embodiments, the first ohmic contact electrode 50 can also serve as a source and be connected to a low potential, and the second ohmic contact electrode 60 can also serve as a drain and be connected to a high potential. At this time, the first ohmic contact electrode 50 serves as the first connection terminal 111 of the bidirectional switching device 110, the second ohmic contact electrode 60 serves as the second connection terminal 113 of the bidirectional switching device 110, and the gate 80 can serve as the third connection terminal 115 of the bidirectional switching device 110. The present application does not impose any restrictions on this.

[0069] For details, please refer to Figure 3 The epitaxial structure 10 includes a substrate 11, a nucleation layer 13, a buffer layer 15, a high-transition layer 17 and a barrier layer 19 which are stacked in sequence. The material of the substrate 11 can be Si, Al 2 O 3 , SiC or GaN. The nucleation layer 13 is disposed on the surface of the substrate 11. The material of the nucleation layer 13 can be AlN or GaN. Exemplarily, the thickness of the nucleation layer 13 can be 50nm to 200nm. The buffer layer 15 is disposed on the surface of the nucleation layer 13 away from the substrate 11. The buffer layer 15 can be AlN / GaN superlattice, Al x Ga 1-x N gradient layer or GaN layer. Exemplarily, the thickness of the buffer layer 15 can be 0.5 μm to 5 μm. The high migration layer 17 is arranged on the surface of the buffer layer 15 away from the substrate 11. The high migration layer 17 can be a GaN layer. Exemplarily, the thickness of the high migration layer 17 can be 10 nm to 200 nm. The barrier layer 19 is arranged on the surface of the high migration layer 17 away from the substrate 11. The barrier layer 19 can be Al x Ga 1-x N-layer, In x Al 1-x N layer or In x Al y Ga 1-x-y N layers. Exemplarily, the thickness of the barrier layer 19 may be 3 nm to 20 nm. In this embodiment, the length of the barrier layer 19 extending along the Y-axis direction is equal to the width W of the bidirectional switch device 110 extending along the Y-axis direction.

[0070] Combined with reference Figure 5, Figure 6 and Figure 7 , Figure 6 for Figure 5 The cross-sectional structure diagram of the bidirectional switch device 110 at AA is shown, Figure 7 for Figure 5 The cross-sectional structure diagram of the bidirectional switch device 110 at position BB is shown. Figure 6 The solid black circles represent electrons, and the hollow black circles represent holes.

[0071] The P-GaN layer 20 is disposed on the surface of the barrier layer 19 facing away from the substrate 11. In this embodiment, the material of the P-GaN layer 20 is Mg-doped gallium nitride (GaN). For example, the doping concentration of Mg in GaN can be 1×10 18 ~5×10 19 cm -3 . Exemplarily, the thickness of the P-GaN layer 20 may be 50nm to 200nm. The length direction of the P-GaN layer 20 is the Y-axis direction, and the width direction is the X-axis direction. In this embodiment, the P-GaN layer 20 extends continuously along the Y-axis direction. Specifically, the P-GaN layer 20 extends continuously from one end of the barrier layer 19 facing the negative direction of the Y-axis to the other end of the barrier layer 19 facing the positive direction of the Y-axis. The width of the P-GaN layer 20 is L P-GaN . For example, L P-GaN The P-GaN layer 20 includes a first end surface 21 (see Figure 5 ) and the second end surface 22 (see Figure 5 ), the first end face 21 and the second end face 22 are arranged opposite to each other along the width direction of the P-GaN layer 20, that is, they are arranged opposite to each other along the X-axis direction. In this embodiment, the first end face 21 faces the positive direction of the X-axis, and the second end face 22 faces the negative direction of the X-axis.

[0072] The first P-GaN island 30 and the second P-GaN island 40 are both arranged on the surface of the barrier layer 19 away from the substrate 11. The first P-GaN island 30 and the second P-GaN island 40 are respectively located on both sides of the P-GaN layer 20 along the width direction, and are spaced apart from the P-GaN layer 20. In this embodiment, the first P-GaN island 30 is located on one side of the P-GaN layer 20 along the positive direction of the X-axis, that is, the first P-GaN island 30 faces the first end face 21, and is opposite to the first end face 21 and is spaced apart. The second P-GaN island 40 is located on one side of the P-GaN layer 20 along the negative direction of the positive axis, that is, the second P-GaN island 40 faces the second end face 22, and is opposite to the second end face 22 and is spaced apart.

[0073] There may be M first P-GaN islands 30, M ≥ 2, and M is a natural number. Exemplarily, the number of first P-GaN islands 30 is 1 to 5. The width of each first P-GaN island 30 along the width direction of the P-GaN layer 20, that is, along the X-axis direction, is L P1-ISO . For example, L P1-ISO It can be 0.1μm to 0.5μm. The M first P-GaN islands 30 are arranged at intervals along the length direction of the P-GaN layer 20, that is, along the Y-axis direction. In this embodiment, the M first P-GaN islands 30 are evenly spaced along the length direction of the P-GaN layer 20, and the distance between two adjacent first P-GaN islands 30 is D1. The length of each first P-GaN island 30 along the length direction of the P-GaN layer 20, that is, along the Y-axis direction, is W1. The sum of the lengths of the M first P-GaN islands 30 is W1 c , the total length W1 of the M first P-GaN islands 30 c The ratio of the length W of the barrier layer 19 extending along the Y-axis direction, that is, the ratio of the width W of the bidirectional switch device 110 is W1. c / W. Exemplary, W1 c / W is 1% to 20%.

[0074] There may be N second P-GaN islands 40, N ≥ 2, and N is a natural number. Exemplarily, the number of second P-GaN islands 40 is 1 to 5. Among them, the number of second P-GaN islands 40 may be equal to or unequal to the number of first P-GaN islands 30. In this embodiment, N = M, that is, the number of second P-GaN islands 40 is equal to the number of first P-GaN islands 30. It can be understood that in other embodiments, N may not be equal to M, that is, the number of second P-GaN islands 40 may not be equal to the number of first P-GaN islands 30, for example, the number of second P-GaN islands 40 is 3, the number of first P-GaN islands 30 is 2, or the number of second P-GaN islands 40 is 2, and the number of first P-GaN islands 30 is 3. In addition, in the present embodiment, each second P-GaN island 40 is mirror-symmetrical with a first P-GaN island 30 about the P-GaN layer 20. It is understandable that in other embodiments, the second P-GaN island 40 may also be staggered with the first P-GaN island 30, that is, the second P-GaN island 40 is asymmetric with the first P-GaN island 30 about the P-GaN layer 20.

[0075] The width of each second P-GaN island 40 along the width direction of the P-GaN layer 20, that is, along the X-axis direction, is L P2-ISO . For example, L P2-ISO It can be 0.1 μm to 0.5 μm. In this embodiment, L P2-ISO =L P1-ISO. The N second P-GaN islands 40 are arranged at intervals along the length direction of the P-GaN layer 20, that is, along the Y-axis direction. The N second P-GaN islands 40 are evenly spaced along the length direction of the P-GaN layer 20, and the distance between two adjacent second P-GaN islands 40 is D2. In this embodiment, D2 = the distance D1 between two adjacent first P-GaN islands 30. The length of each second P-GaN island 40 along the length direction of the P-GaN layer 20, that is, along the Y-axis direction, is W2. The total length of the N second P-GaN islands 40 is W2 c The total width W2 of the N second P-GaN islands 40 is c The ratio of the length W of the barrier layer 19 extending along the Y-axis direction, that is, the ratio of the width W of the bidirectional switch device 110 is W2 c / W. Exemplary, W2 c / W is 1% to 20%.

[0076] Combined with reference Figure 5 and Figure 6 The first ohmic contact electrode 50 is disposed on the surface of the barrier layer 19 away from the substrate 11, and is located on the side of the M first P-GaN islands 30 away from the P-GaN layer 20, and is electrically connected to the M first P-GaN islands 30. The material of the first ohmic contact electrode 50 can be selected from an ohmic metal system. Exemplarily, the first ohmic contact electrode 50 can be Ti / Al / TiN, Ti / Al / Ti / Au or Ti / Al / Ni / Au.

[0077] In this embodiment, the first ohmic contact electrode 50 is in ohmic contact with the first P-GaN island 30 to achieve electrical connection between the first ohmic contact electrode 50 and the first P-GaN island 30. Here, "ohmic contact" means that a non-rectifying contact can be formed when a metal contacts a semiconductor. In addition, in this embodiment, the projection of the first ohmic contact electrode 50 on the surface of the barrier layer 19 at least partially covers the spacing area formed between two adjacent first P-GaN islands 30. Specifically, the first ohmic contact electrode 50 includes a first electrode portion 51 and a second electrode portion 52. In this embodiment, the first electrode portion 51 and the second electrode portion 52 are both extended continuously along the length direction of the P-GaN layer 20, that is, along the Y-axis direction. The first electrode portion 51 is provided on the surface of the barrier layer 19 away from the substrate 11, and is located on the side of the first P-GaN island 30 away from the P-GaN layer 20, and is spaced apart from the first P-GaN island 30. The second electrode portion 52 is disposed on the surface of the first electrode portion 51 away from the barrier layer 19 , and is connected between the first electrode portion 51 and the surface of each first P-GaN island 30 away from the barrier layer 19 , so as to achieve ohmic contact between the first ohmic contact electrode 50 and each first P-GaN island 30 .

[0078] In this embodiment, the projection of the second electrode portion 52 on the surface of the barrier layer 19 at least partially covers the area between the first electrode portion 51 and the first P-GaN, and at least partially covers the spacing area formed between two adjacent first P-GaN islands 30, so as to achieve that the projection of the first ohmic contact electrode 50 on the surface of the barrier layer 19 at least partially covers the spacing area formed between two adjacent first P-GaN islands 30.

[0079] The second ohmic contact electrode 60 is disposed on the surface of the barrier layer 19 away from the substrate 11, and is located on the side of the N second P-GaN islands 40 away from the P-GaN layer 20, and is electrically connected to the N second P-GaN islands 40. The material of the second ohmic contact electrode 60 can be selected from an ohmic metal system. Exemplarily, the second ohmic contact electrode 60 can be Ti / Al / TiN, Ti / Al / Ti / Au or Ti / Al / Ni / Au. In this embodiment, the distance between the second ohmic contact electrode 60 and the first ohmic contact electrode 50 is L D1D2 . For example, L D1D2 It can be 1 μm to 3 μm.

[0080] In the present embodiment, the second ohmic contact electrode 60 is in ohmic contact with the second P-GaN island 40 to achieve electrical connection between the second ohmic contact electrode 60 and the second P-GaN island 40. In addition, in the present embodiment, the projection of the second ohmic contact electrode 60 on the surface of the barrier layer 19 at least partially covers the spacing area formed between two adjacent second P-GaN islands 40. Specifically, the second ohmic contact electrode 60 includes a first portion 61 and a second portion 62. In the present embodiment, the first portion 61 and the second portion 62 both extend continuously along the length direction of the P-GaN layer 20, that is, along the Y-axis direction. The first portion 61 is provided on the surface of the barrier layer 19 away from the substrate 11, and is located on the side of the second P-GaN island 40 away from the P-GaN layer 20, and is spaced apart from the second P-GaN island 40. The second portion 62 is disposed on the surface of the first portion 61 away from the barrier layer 19 and connected between the first portion 61 and the surface of each second P-GaN island 40 away from the barrier layer 19 to achieve ohmic contact between the second ohmic contact electrode 60 and each second P-GaN island 40 .

[0081] In this embodiment, the projection of the second part 62 on the surface of the barrier layer 19 at least partially covers the area between the first part 61 and the second P-GaN island 40, and at least partially covers the spacing area formed between two adjacent second P-GaN islands 40, so as to achieve that the projection of the second ohmic contact electrode 60 on the surface of the barrier layer 19 at least partially covers the spacing area formed between two adjacent second P-GaN islands 40.

[0082] The first passivation layer 70 is disposed on the surface of the barrier layer 19 facing away from the substrate 11. The first passivation layer 70 is connected between the first ohmic contact electrode 50 and the second ohmic contact electrode 60, and covers the peripheral surface of the P-GaN layer 20, the peripheral surface of the first P-GaN island 30, and the peripheral surface of the second P-GaN island 40. For example, the first passivation layer 70 may be Si 3 N 4 Or SiO 2 Materials: Exemplarily, the thickness of the first passivation layer 70 may be 10 nm to 200 nm.

[0083] Specifically, the first passivation layer 70 includes a first passivation portion 71 and a second passivation portion 72. The first passivation portion 71 fills the gap between the P-GaN layer 20 and the first electrode portion 51, so that the first passivation layer 70 is connected between the P-GaN layer 20 and the first ohmic contact electrode 50, and covers part of the circumference of the P-GaN layer 20. At this time, the first passivation portion 71 is arranged around the circumference of each first P-GaN island 30, and covers the circumference of each first P-GaN island 30. The second passivation portion 72 fills the gap between the P-GaN layer 20 and the first portion 61, so that the first passivation layer 70 is connected between the P-GaN layer 20 and the second ohmic contact electrode 60, and covers part of the circumference of the P-GaN layer 20. At this time, the second passivation portion 72 is arranged around the circumference of each second P-GaN island 40, and covers the circumference of each second P-GaN island 40.

[0084] The gate 80 is disposed on the surface of the P-GaN layer 20 away from the barrier layer 19, so that the gate 80 is disposed on the side of the P-GaN layer 20 away from the epitaxial structure 10. In this embodiment, the gate 80 extends continuously along the length direction of the P-GaN layer 20, that is, along the Y-axis direction. Exemplarily, the gate 80 can be TiN / Al or Ni / Au. In this embodiment, the width of the gate 80 is L Gate .L Gate The thickness of the gate electrode 80 may be 0.2 μm to 0.4 μm. The gate electrode 80 includes a third end face 81 and a fourth end face 82, and the third end face 81 and the fourth end face 82 are arranged opposite to each other along the width direction of the gate electrode 80. In this embodiment, the first end face 21 of the P-GaN layer 20 protrudes toward the positive direction of the X-axis relative to the third end face 81 of the gate electrode 80, and the second end face 22 protrudes toward the negative direction of the X-axis relative to the fourth end face 82 of the gate electrode 80, so that the two end faces of the P-GaN layer 20 along the width direction protrude relative to the two end faces of the gate electrode 80 along the width direction of the P-GaN layer 20.

[0085] Continue reading Figure 5 and Figure 6In the bidirectional switch device 110 provided in this embodiment, the first ohmic contact electrode 50 is used as a drain and connected to a high potential, and the second ohmic contact electrode 60 is used as a source and connected to a low potential such as ground.

[0086] See also Figure 5 When the voltage between the gate 80 and the second ohmic contact electrode 60 is greater than the threshold voltage of the bidirectional switch device 110, a conductive channel is formed under the gate 80, the bidirectional switch device 110 is turned on, and the current can flow from the first ohmic contact electrode 50 to the second ohmic contact electrode 60. However, since the second ohmic contact electrode 60 is connected to a low potential, the second P-GaN island 40 under the second ohmic contact electrode 60 does not form a conductive channel, and the current flowing from the first ohmic contact electrode 50 to the second ohmic contact electrode 60 will be separated by the second P-GaN island 40. The current flow is as follows: Figure 5 As shown by the arrow in the middle. The introduction of the second P-GaN island 40 limits the flow direction of the current of the bidirectional switch device 110, so that the current flowing from the first ohmic contact electrode 50 to the second ohmic contact electrode 60 can only flow out from the channel formed between the two adjacent second P-GaN islands 40, so that the second ohmic contact electrode 60 has a gathering effect on the current. At this time, the second P-GaN island 40 blocks the current flowing through, generates a very high impedance, reduces the current flowing through, thereby helping to reduce the power consumption of the bidirectional switch device 110, and further can improve the short-circuit tolerance of the bidirectional switch device 110.

[0087] See also Figure 6, when the voltage between the gate 80 and the second ohmic contact electrode 60 is less than the threshold voltage of the bidirectional switch device 110, the channel under the gate 80 is closed, and the bidirectional switch device 110 is turned off. There is a strong electric field on the side of the gate 80 close to the first ohmic contact electrode 50, and the electrons in the metal of some gates 80 can be excited to become free electrons. Under the action of the electric field, the free electrons move from the gate 80 to the first ohmic contact electrode 50 along the surface of the barrier layer 19. Generally, due to material defects or process damage, there is often a high density of trap surface states on the surface of the barrier layer 19. During the movement of the free electrons on the surface of the barrier layer 19, they are easily captured by the trap surface states on the barrier layer 19. The captured electrons consume the two-dimensional electron gas in the channel under the barrier layer 19, resulting in the phenomenon of increased channel impedance and reduced output current, which is the so-called "current collapse effect". The present application arranges the first P-GaN island 30 on the side of the first ohmic contact electrode 50, and forms an ohmic contact between the first ohmic contact electrode 50 and the surface of the first P-GaN island 30. The first P-GaN island 30 will form holes under the high voltage condition of the first ohmic contact electrode 50, and the holes of the first P-GaN island 30 will be injected into the barrier layer 19 in a direction perpendicular to the surface of the barrier layer 19. The injected holes will neutralize the electrons captured by the surface traps of the barrier layer 19, thereby effectively alleviating or even eliminating the "current collapse effect" of the bidirectional switch device 110, and improving the reliability of the bidirectional switch device 110.

[0088] It can be understood that when the first ohmic contact electrode 50 in the bidirectional switch device 110 is connected to a low potential as a source, and the second ohmic contact electrode 60 is connected to a high potential as a drain. At this time, when the voltage between the gate 80 and the first ohmic contact electrode 50 is greater than the threshold voltage of the bidirectional switch device 110, a conductive channel is formed under the gate 80. The current flowing from the second ohmic contact electrode 60 to the first ohmic contact electrode 50 will be separated by the first P-GaN island 30, so that the first ohmic contact electrode 50 has a gathering effect on the current. The first P-GaN island 30 blocks the current flowing through, generates a very high impedance, reduces the current flowing through, thereby helping to reduce the power consumption of the bidirectional switch device 110, and then helps to improve the short-circuit tolerance of the bidirectional switch device 110. When the voltage between the gate 80 and the first ohmic contact electrode 50 is less than the threshold voltage of the bidirectional switch device 110, the channel under the gate 80 is closed. By arranging the second P-GaN island 40 on the side of the second ohmic contact electrode 60, and making the second ohmic contact electrode 60 form an ohmic contact with the surface of the second P-GaN island 40, the holes formed by the second P-GaN island 40 under the high voltage condition of the second ohmic contact electrode 60 can be injected into the barrier layer 19 in a direction perpendicular to the surface of the barrier layer 19, and neutralized with the electrons captured by the surface traps of the barrier layer 19, thereby effectively alleviating or even eliminating the "current collapse effect" of the bidirectional switch device 110, and improving the reliability of the bidirectional switch device 110.

[0089] The bidirectional switch device 110 provided in the embodiment of the present application, by simultaneously setting the first P-GaN island 30 on the side of the first ohmic contact electrode 50 and setting the second P-GaN island 40 on the side of the second ohmic contact electrode 60, ensures the short-circuit tolerance and reliability of the bidirectional switch device 110, and the bidirectional switch device 110 does not need to distinguish between the first ohmic contact electrode 50 and the second ohmic contact electrode 60 when in use, and is more convenient to use. Compared with the existing silicon (Si)-based MOS devices, the bidirectional switch device 110 provided in the embodiment of the present application is a high electron mobility transistor (HEMT) device based on gallium nitride (GaN), which does not require a body diode, solves the problem of the existing need to use two silicon (Si)-based MOS devices to achieve bidirectional shutdown, resulting in a large occupied area, and the bidirectional switch device 110 in the embodiment of the present application occupies a small area, which is conducive to the miniaturization of the assembled electronic device 1. On the other hand, the gallium nitride (GaN) material used has a higher critical electric field, unique and excellent dynamic on-resistance, and lower capacitance, which makes the bidirectional switch device have the advantages of fast switching speed, low on-resistance and high breakdown voltage, and has good application prospects in consumer electronics, data centers, industrial control and other fields.

[0090] In addition, by setting the sum of the lengths W1 of the M first P-GaN islands 30 c The ratio W1 of the length W of the barrier layer 19 c / W=1%~20%, which ensures that the width of the channel between adjacent first P-GaN islands 30 is wide enough, and the impedance of the first P-GaN island 30 to the current is not particularly large, thereby facilitating the normal operation of the bidirectional switch device 110. Similarly, by setting the total length W2 of the N second P-GaN islands 40 to c The ratio W2 of the length W of the barrier layer 19 c / W=1%-20%, which ensures that the width of the channel between adjacent second P-GaN islands 40 is wide enough, and the impedance of the second P-GaN islands 40 to the current is not particularly large, thereby facilitating the normal operation of the bidirectional switch device 110.

[0091] In addition, when the bidirectional switch device 110 is in the off state, the electric field will gather on both sides of the gate 80 and the P-GaN layer 20 along the width direction of the P-GaN layer 20. In the embodiment of the present application, M first P-GaN islands 30 are arranged to be spaced apart from each other, and the projection of the first ohmic contact electrode 50 on the surface of the barrier layer 19 covers the spaced area formed between the M first P-GaN islands 30, so that the portion of the first ohmic contact electrode 50 covering the spaced area between the M first P-GaN islands 30 can act as a field plate structure, which can attract the electric field, so that the electric field gathered at the corners of the gate 80 and the P-GaN layer 20 can be dispersed, thereby facilitating the improvement of the breakdown voltage of the bidirectional switch device 110. In addition, in the embodiment of the present application, N second P-GaN islands 40 are arranged to be spaced apart from each other, and the projection of the second ohmic contact electrode 60 on the surface of the barrier layer 19 covers the spacing area formed between the N second P-GaN islands 40, so that the part of the second ohmic contact electrode 60 covering the spacing area between the N second P-GaN islands 40 can act as a field plate structure, which can attract the electric field, thereby dispersing the electric field gathered at the corners of the gate 80 and the P-GaN layer 20, thereby facilitating the improvement of the breakdown voltage of the bidirectional switch device 110.

[0092] See also Figure 8 , Figure 8 FIG. 1 is a schematic structural diagram of the bidirectional switch device 110 in the second embodiment.

[0093] The bidirectional switch device 110 of the second embodiment is different from the bidirectional switch device 110 of the first embodiment in that the bidirectional switch device 110 of the second embodiment further includes a second passivation layer 90 , a first electrical connection 94 , a second electrical connection 95 and a third electrical connection 96 .

[0094] Specifically, the second passivation layer 90 is disposed on the side of the first ohmic contact electrode 50, the second ohmic contact electrode 60 and the gate 80 away from the barrier layer 19, and covers the first passivation layer 70. Exemplarily, the thickness of the second passivation layer 90 may be 200nm to 500nm. Exemplarily, the material of the second passivation layer 90 may be Si 3 N 4 Or SiO 2 Material.

[0095] In this embodiment, the second passivation layer 90 is provided with a first hole 91, a second hole 92 and a third hole 93. The first hole 91 penetrates the second passivation layer 90 along the thickness direction of the second passivation layer 90 and exposes a portion of the surface of the first ohmic contact electrode 50. The second hole 92 penetrates the second passivation layer 90 along the thickness direction of the second passivation layer 90 and exposes a portion of the surface of the second ohmic contact electrode 60. The third hole 93 penetrates the second passivation layer 90 along the thickness direction of the second passivation layer 90 and exposes a portion of the surface of the gate 80.

[0096] The first electrical connector 94, the second electrical connector 95 and the third electrical connector 96 are all provided through the second passivation layer 90 along the thickness direction of the second passivation layer 90. Among them, the first electrical connector 94 is electrically connected to the first ohmic contact electrode 50, the second electrical connector 95 is electrically connected to the second ohmic contact electrode 60, and the third electrical connector 96 is electrically connected to the gate 80. Exemplarily, the first electrical connector 94, the second electrical connector 95 and the third electrical connector 96 can be Ti / Au respectively. Specifically, the first electrical connector 94 is connected between the hole wall of the first hole 91 and the partial surface of the first ohmic contact electrode 50 away from the barrier layer 19 to realize the electrical connection between the first electrical connector 94 and the first ohmic contact electrode 50. The second electrical connector 95 is connected between the hole wall of the second hole 92 and the partial surface of the second ohmic contact electrode 60 away from the barrier layer 19 to realize the electrical connection between the second electrical connector 95 and the second ohmic contact electrode 60. The third electrical connection member 96 is connected between the hole wall of the third hole 93 and a portion of the surface of the gate 80 facing away from the P-GaN layer 20 , so as to achieve electrical connection between the third electrical connection member 96 and the gate 80 .

[0097] In the bidirectional switch device 110 of this embodiment, the second passivation layer 90 can enhance the protection of the surface of the bidirectional switch device 110 and further reduce the influence of oxygen or water vapor in the air on the surface of the bidirectional switch device 110. The first electrical connector 94, the second electrical connector 95 and the third electrical connector 96 can be used to interconnect with external devices, thereby realizing the electrical connection between the bidirectional switch device 110 and the external devices.

[0098] See also Fig. 9 , Fig.10 and Fig.11 , Fig. 9for Figure 3 The schematic diagram of the preparation process of the bidirectional switch device 110 is shown in FIG. Fig.10 for Figure 3 A schematic diagram of some preparation steps of the structure of the bidirectional switch device 110 is shown, Fig.11 for Figure 3 A schematic diagram of another part of the preparation steps of the structure of the bidirectional switch device 110 is shown.

[0099] The present application also provides a method for preparing a bidirectional switch device 110 according to the second embodiment, including:

[0100] An epitaxial structure 10 is provided, and the epitaxial structure 10 includes a barrier layer 19. In this embodiment, the surface of the barrier layer 19 includes a first region 191, a second region 192, a third region 193, a fourth region 194, and a fifth region 195. The second region 192 and the third region 193 are located on both sides of the first region 191 along the width direction, and are both spaced apart from the first region 191. There are M second regions 192, and N third regions 193, M≥2, N≥2, and M and N are both natural numbers. The M second regions 192 are spaced apart along the length direction of the first region 191, and the N third regions 193 are spaced apart along the length direction of the first region 191. The fourth region 194 is located on a side of the second region 192 away from the first region 191, and is spaced apart from the second region 192. The fifth region 195 is located on a side of the third region 193 away from the first region 191, and is spaced apart from the third region 193.

[0101] A P-GaN material layer is prepared on the surface of the barrier layer 19, and the P-GaN material layer is patterned to obtain a P-GaN layer 20, M first P-GaN islands 30, and N second P-GaN islands 40. In the present embodiment, a P-GaN material layer is prepared on the surface of the barrier layer 19, and the P-GaN material layer covering the first region 191, the second region 192, and the third region 193 is etched and retained, and the portion of the P-GaN material layer covering the first region 191 forms the P-GaN layer 20, the portion of the P-GaN material layer covering the second region 192 forms the M first P-GaN islands 30, and the portion of the P-GaN material layer covering the third region 193 forms the N second P-GaN islands 40. In this embodiment, a P-GaN material layer is first prepared on the surface of the barrier layer 19 , and then the P-GaN material layer is etched using a Cl-based gas to retain the P-GaN material layer covering the first region 191 , the second region 192 , and the third region 193 , and the remaining regions stop at the surface of the barrier layer 19 .

[0102] A first passivation layer 70 is formed on the surface of the barrier layer 19. The first passivation layer 70 covers the peripheral surface of the P-GaN layer 20, the peripheral surface of the first P-GaN island 30, and the peripheral surface of the second P-GaN island 40. In this embodiment, a layer of Si is grown by plasma enhanced chemical vapor deposition (PECVD). 3 N 4 Or SiO 2 The material serves as the first passivation layer 70. The first passivation layer 70 covers the fourth region 194, the fifth region 195 and the surface of the P-GaN layer 20 away from the barrier layer 19. The first passivation layer 70 can passivate the surface of the bidirectional switch device 110, and the first passivation layer 70 can be used to reduce the surface traps of the barrier layer 19 in the bidirectional switch device 110 and reduce the current collapse effect.

[0103] The first passivation layer 70 is etched to expose a portion of the surface of the barrier layer 19, and a first ohmic contact electrode 50 and a second ohmic contact electrode 60 are prepared on the surface of the exposed barrier layer 19. The first ohmic contact electrode 50 is located on a side of the M first P-GaN islands 30 away from the P-GaN layer 20, and is electrically connected to each of the first P-GaN islands 30. The second ohmic contact electrode 60 is located on a side of the N second P-GaN islands 40 away from the P-GaN layer 20, and is electrically connected to each of the second P-GaN islands 40. In this embodiment, the first passivation layer 70 is etched using a F-based gas to expose the fourth region 194 and the fifth region 195, and then ohmic metal is deposited in the fourth region 194 and the fifth region 195, and then annealed in a rapid annealing furnace to form a first ohmic contact electrode 50 and a second ohmic contact electrode 60, the first ohmic contact electrode 50 covers the fourth region 194, the surface of the first passivation layer 70 away from the barrier layer 19, and the surface of the M first P-GaN islands 30 away from the barrier layer 19, and the second ohmic contact electrode 60 covers the fifth region 195, the surface of the first passivation layer 70 away from the barrier layer 19, and the surface of the N second P-GaN islands 40 away from the barrier layer 19. The annealing time and temperature depend on the selected ohmic metal system. During the annealing process, the first passivation layer 70 can also protect the surface structure of the bidirectional switch device 110 from being damaged.

[0104] The first passivation layer 70 is etched to expose the surface of the P-GaN layer 20 away from the barrier layer 19, and a gate 80 is prepared on the surface of the P-GaN layer 20 away from the barrier layer 19. In this embodiment, the first passivation layer 70 is etched to expose the surface of the P-GaN layer 20, and a gate 80 is prepared on the surface of the P-GaN layer 20 away from the barrier layer 19. In this embodiment, the first passivation layer 70 corresponding to the gate 80 region is etched using a F-based gas until the surface of the P-GaN layer 20 away from the barrier layer 19 is exposed. Then a layer of gate 80 metal is deposited on the exposed surface of the P-GaN layer 20 away from the barrier layer 19 to prepare the gate 80.

[0105] A second passivation layer 90 is prepared, and the second passivation layer 90 covers the first ohmic contact electrode 50, the second ohmic contact electrode 60, the first passivation layer 70 and the surface of the gate 80 away from the barrier layer 19. In this embodiment, a layer of Si is deposited by PECVD. 3 N 4 Or SiO 2 The material serves as the second passivation layer 90 . The second passivation layer 90 can enhance the protection of the surface of the bidirectional switch device 110 and further reduce the influence of oxygen or water vapor in the air on the surface of the bidirectional switch device 110 .

[0106] The second passivation layer 90 is etched to expose the partial surfaces of the first ohmic contact electrode 50, the second ohmic contact electrode 60 and the gate 80 away from the barrier layer 19, and a first electrical connector 94 is prepared on the surface of the first ohmic contact electrode 50 away from the barrier layer 19, a second electrical connector 95 is prepared on the surface of the second ohmic contact electrode 60 away from the barrier layer 19, and a third electrical connector 96 is prepared on the surface of the gate 80 away from the barrier layer 19. In this embodiment, the partial regions of the second passivation layer 90 corresponding to the first ohmic contact electrode 50, the second ohmic contact electrode 60 and the gate 80 are etched and opened respectively by using a gas containing a F group until the surfaces of the first ohmic contact electrode 50, the second ohmic contact electrode 60 and the gate 80 away from the barrier layer 19 are exposed, thereby preparing a first hole 91, a second hole 92 and a third hole 93. Finally, Ti / Au is deposited in the first hole 91, the second hole 92, and the third hole 93 as the Pad interconnection metal, so as to obtain the first electrical connection 94 in the first hole 91, the second electrical connection 95 in the second hole 92, and the third electrical connection 96 in the third hole 93, respectively, to complete the preparation of the bidirectional switch device 110. At this time, the first electrical connection 94 is electrically connected to a portion of the surface of the first ohmic contact electrode 50, the second electrical connection 95 is electrically connected to a portion of the surface of the second ohmic contact electrode 60, and the third electrical connection 96 is electrically connected to a portion of the surface of the gate 80, so that the bidirectional switch device 110 is electrically connected to external devices through the first electrical connection 94, the second electrical connection 95, and the third electrical connection 96.

[0107] See also Fig.12 and Fig.13 , Fig.12 is a schematic structural diagram of a bidirectional switch device 110 in a third embodiment, Fig.13 for Fig.12 A schematic top view of the structure of the bidirectional switch device 110 is shown.

[0108] The bidirectional switch device 110 of the third embodiment is different from the bidirectional switch device 110 of the second embodiment in that the bidirectional switch device 110 of the third embodiment further includes a first field plate 97 .

[0109] Combined with reference Fig.14 and Fig.15 , Fig.14 for Fig.12 The cross-sectional structure diagram of the bidirectional switch device 110 at AA is shown, Fig.15 for Fig.12 The schematic diagram of the cross-sectional structure of the bidirectional switch device 110 at BB is shown. Specifically, the first field plate 97 is arranged on the surface of the second passivation layer 90 away from the barrier layer 19. There can be multiple first field plates 97, and the multiple first field plates 97 include a first plate 971 and a second plate 972, and the first plate 971 and the second plate 972 are both arranged on the surface of the second passivation layer 90 away from the barrier layer 19. Along the width direction of the P-GaN layer 20, that is, along the X-axis direction, the projections of the first plate 971 and the second plate 972 on the P-GaN layer 20 are respectively located on opposite sides of the gate 80. In this embodiment, there are two first field plates 97, one first field plate 97 is the first plate 971, and the other first field plate 97 is the second plate 972. Exemplarily, in this embodiment, the first field plate 97 is prepared before the steps of preparing the first electrical connector 94, the second electrical connector 95 and the third electrical connector 96.

[0110] In the bidirectional switch device 110 provided in this embodiment, the breakdown voltage of the bidirectional switch device 110 can be increased by providing the first field plate 97. In addition, the first field plate 97 of this embodiment floats above the gate 80 and is not electrically connected to the gate 80, so that the potentials of the first field plate 97 and the gate 80 can be adjusted separately.

[0111] See also Fig.16 and Fig.17 , Fig.16 is a schematic structural diagram of the bidirectional switch device 110 in the fourth embodiment, Fig.17 for Fig.16 A schematic top view of the structure of the bidirectional switch device 110 is shown.

[0112] The bidirectional switch device 110 of the fourth embodiment is different from the bidirectional switch device 110 of the second embodiment in that the bidirectional switch device 110 of the third embodiment further includes a second field plate 98 .

[0113] Combined with reference Fig.18 and Fig.19 , Fig.18 for Fig.17 The cross-sectional structure diagram of the bidirectional switch device 110 at AA is shown, Fig.19 for Fig.17 The schematic diagram of the cross-sectional structure of the bidirectional switch device 110 at BB is shown. Specifically, the second field plate 98 is arranged in the second passivation layer 90 and is electrically connected to the gate 80. Among them, there can be multiple second field plates 98, and the multiple second field plates include a first sub-plate 981 and a second sub-plate 982, and the first sub-plate 981 and the second sub-plate 982 are both arranged in the second passivation layer 90. Along the width direction of the P-GaN layer, that is, along the X-axis direction, the first sub-plate 981 and the second sub-plate 982 are respectively located on opposite sides of the gate 80, and are both electrically connected to the gate 80. In this embodiment, there are two second field plates 98, one second field plate 98 is the first sub-plate 981, and the other second field plate 98 is the second sub-plate 982, and the first sub-plate 981 and the second sub-plate 982 are both protruding from the surface of the gate 80 away from the P-GaN layer 20 along the thickness direction of the gate 80 relative to the gate 80. Illustratively, in this embodiment, before the steps of preparing the first electrical connector 94 , the second electrical connector 95 , and the third electrical connector 96 , the second field plate 98 is prepared.

[0114] In the bidirectional switch device 110 provided in this embodiment, the breakdown voltage of the bidirectional switch device 110 can be increased by providing the second field plate 98. In addition, the second field plate 98 of this embodiment is electrically connected to the gate 80, and the second field plate 98 and the gate 80 can be completed at the same time when the gate 80 is prepared, and the process is relatively simple.

[0115] What is disclosed above is only a preferred embodiment of the present application, and it certainly cannot be used to limit the scope of rights of the present application. Ordinary technicians in this field can understand that all or part of the processes of implementing the above embodiments and equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. A bidirectional switch device, It is characterized in that The bidirectional switch device comprises an epitaxial structure, a P-GaN layer, a first P-GaN island, a second P-GaN island, a first ohmic contact electrode, a second ohmic contact electrode and a gate, the epitaxial structure comprises a barrier layer, the P-GaN layer, the first P-GaN island, the second P-GaN island, the first ohmic contact electrode and the second ohmic contact electrode are all arranged on the same surface of the barrier layer, wherein along the width direction of the P-GaN layer, the first P-GaN island and the second P-GaN island are respectively located on both sides of the P-GaN layer, and are both spaced apart from the P-GaN layer, there are M first P-GaN islands, there are N second P-GaN islands, M≥2, N≥2, and both M and N are natural numbers, along the length direction of the P-GaN layer, M first P-GaN islands are spaced apart, and N second P-GaN islands are spaced apart; The first ohmic contact electrode is located on a side of the M first P-GaN islands away from the P-GaN layer, and is electrically connected to each of the first P-GaN islands; The second ohmic contact electrode is located on a side of the N second P-GaN islands away from the P-GaN layer, and is electrically connected to each of the second P-GaN islands; The gate is disposed on a surface of the P-GaN layer away from the barrier layer, and is spaced apart from the first ohmic contact electrode and the second ohmic contact electrode.

2. The bidirectional switch device according to claim 1, It is characterized in that Along the length direction of the P-GaN layer, the length of the barrier layer is W, and the total length of the M first P-GaN islands is W1 c , W1 c / W=1%~20%, the total length of the N second P-GaN islands is W2 c , W2 c / W=1%~20%.

3. The bidirectional switch device according to claim 1, It is characterized in that The M first P-GaN islands are evenly spaced, and the distance between two adjacent first P-GaN islands is D1; ​​the N second P-GaN islands are evenly spaced, and the distance between two adjacent second P-GaN islands is D2, and D1=D2.

4. The bidirectional switch device according to claim 1, It is characterized in that M=N, and each of the second P-GaN islands is mirror-symmetrical to one of the first P-GaN islands with respect to the P-GaN layer.

5. The bidirectional switch device according to any one of claims 1 to 4, It is characterized in that The projection of the first ohmic contact electrode on the surface of the barrier layer at least partially covers the area between two adjacent first P-GaN islands.

6. The bidirectional switch device according to claim 5, It is characterized in that The first ohmic contact electrode includes a first electrode portion and a second electrode portion, the first electrode portion is arranged on the surface of the barrier layer and is located on the side of the first P-GaN island away from the P-GaN layer, and is spaced apart from the first P-GaN island, the second electrode portion is arranged on the surface of the first electrode portion away from the barrier layer, and is connected between the first electrode portion and each of the first P-GaN islands, and the projection of the second electrode portion on the surface of the barrier layer at least partially covers the area spaced between the first electrode portion and the first P-GaN island, and at least partially covers the area spaced between two adjacent first P-GaN islands.

7. The bidirectional switch device according to claim 5, It is characterized in that The projection of the second ohmic contact electrode on the surface of the barrier layer at least partially covers the area between two adjacent second P-GaN islands.

8. The bidirectional switch device according to any one of claims 1 to 4, It is characterized in that Along the width direction of the P-GaN layer, the width of each of the first P-GaN islands is L P1-ISO , L P1-ISO =0.1μm~0.5μm, the width of each of the second P-GaN islands is L P2-ISO , L P2-ISO =0.1μm~0.5μm.

9. The bidirectional switch device according to any one of claims 1 to 4, It is characterized in that The width of the P-GaN layer is L P-GaN , L P-GaN =0.1μm~0.5μm.

10. The bidirectional switch device according to any one of claims 1 to 4, It is characterized in that The bidirectional switch device also includes a first passivation layer, which is arranged on the surface of the barrier layer, connected between the first ohmic contact electrode and the second ohmic contact electrode, and covers the peripheral surface of the P-GaN layer, the peripheral surface of the first P-GaN island, and the peripheral surface of the second P-GaN island.

11. The bidirectional switch device according to claim 10, It is characterized in that The bidirectional switch device also includes a second passivation layer and a first field plate. The second passivation layer is arranged on a side of the first ohmic contact electrode, the second ohmic contact electrode and the gate away from the barrier layer and covers the first passivation layer. The first field plate is arranged on a surface of the second passivation layer away from the barrier layer.

12. The bidirectional switch device according to claim 11, It is characterized in that There are multiple first field plates, including a first plate and a second plate. The first plate and the second plate are both arranged on the surface of the second passivation layer away from the barrier layer. Along the width direction of the P-GaN layer, the projections of the first plate and the second plate on the P-GaN layer are respectively located on opposite sides of the gate.

13. The bidirectional switch device according to claim 10, It is characterized in that The bidirectional switch device also includes a second passivation layer and a second field plate. The second passivation layer is arranged on the side of the first ohmic contact electrode, the second ohmic contact electrode and the gate away from the barrier layer and covers the first passivation layer. The second field plate is arranged in the second passivation layer and is electrically connected to the gate.

14. The bidirectional switch device according to claim 13, It is characterized in that There are multiple second field plates, and the multiple second field plates include a first sub-plate and a second sub-plate. The first sub-plate and the second sub-plate are both arranged in the second passivation layer. Along the width direction of the P-GaN layer, the first sub-plate and the second sub-plate are respectively located on opposite sides of the gate and are both electrically connected to the gate.

15. An electronic device, It is characterized in that It includes a power module, a controller and at least two charging links, each of the charging links includes a charging access terminal and a bidirectional switch device as described in any one of claims 1 to 14, the charging access terminal is used to connect to an external power supply, the first ohmic contact electrode is electrically connected to the charging access terminal, the second ohmic contact electrode is electrically connected to the power module, and the gate is electrically connected to the controller.

16. The electronic device according to claim 15, It is characterized in that The at least two charging links include a first charging link and a second charging link, the charging access end of the first charging link is a wireless charging access end, and the charging access end of the second charging link is a wired charging access end.

17. A method for preparing a bidirectional switch device, It is characterized in that include: providing an epitaxial structure, the epitaxial structure comprising a barrier layer; A P-GaN material layer is prepared on the surface of the barrier layer, and the P-GaN material layer is patterned to obtain a P-GaN layer, M first P-GaN islands, and N second P-GaN islands, where M≥2, N≥2, and M and N are both natural numbers, and along the width direction of the P-GaN layer, the first P-GaN islands and the second P-GaN islands are respectively located on both sides of the P-GaN layer, and are both spaced apart from the P-GaN layer; Preparing a first passivation layer on the surface of the barrier layer, wherein the first passivation layer covers the peripheral surface of the P-GaN layer, the peripheral surface of the first P-GaN island, and the peripheral surface of the second P-GaN island; Etching the first passivation layer to expose the surface of the barrier layer, and preparing a first ohmic electrode and a second ohmic electrode on the surface of the exposed barrier layer, wherein the first ohmic electrode is located on a side of the M first P-GaN islands away from the P-GaN layer, and is electrically connected to each of the first P-GaN islands, and the second ohmic contact electrode is located on a side of the N second P-GaN islands away from the P-GaN layer, and is electrically connected to each of the second P-GaN islands; The first passivation layer is etched to expose a surface of the P-GaN layer away from the barrier layer, and a gate is prepared on the surface of the P-GaN layer away from the barrier layer.

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