A GaN bidirectional device with common gate structure

Abstract

The application belongs to the technical field of semiconductor, and particularly discloses a GaN bidirectional device with a common gate structure, which comprises a main body structure, a common gate structure and an outer ring structure, the outer ring structure is arranged around the inner circle of the cutting path, the main body structure comprises alternately arranged first main body units and second main body units, the first main body unit comprises a first source electrode and a first gate structure, and the second main body unit comprises a second source electrode and a second gate structure; the common gate structure comprises two drain electrodes, two third source electrodes and two resistors, the two resistors are connected in series, each third source electrode is connected with one resistor, and the two drain electrodes are connected with the first source electrode and the second source electrode, or the first gate structure and the second gate structure; one connection node between the two resistors is set as a low potential end, and the low potential end is connected with the outer ring structure and / or a substrate. The GaN bidirectional device can always extract a low potential during the working process of the device, and effectively improves the reliability of the device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of semiconductors, and particularly relates to a GaN bidirectional device containing a common gate structure. BACKGROUND

[0002] At present, bidirectional switches are involved in many fields, such as the photovoltaic industry, vehicle-mounted chargers, circuit breakers and the like. The traditional method of bidirectional devices is to use two high-voltage devices in opposite directions in series, but the on-resistance is doubled, and there are many disadvantages such as high cost of multiple devices.

[0003] Power GaN devices have many advantages such as high power density, high switching frequency and low dynamic loss, and in recent years, whether theoretical research or commercial promotion has made great progress, and there is a trend of replacing silicon devices in some fields. Power GaN devices are two-dimensional electron conduction in the horizontal direction, and have no strict directionality, so they are naturally easy to realize bidirectional devices.

[0004] At present, GaN bidirectional devices mainly include common-drain structures and common-source structures. The advantage of the common-source structure is that it can be controlled by one gate, but the depletion region and the drain electrode are not shared, so that the channel length is basically doubled, resulting in an increase in on-resistance. The common-drain structure has the advantages of cost and size due to the sharing of the drain electrode and the depletion region, so that the channel length does not increase and the on-resistance does not increase. It is the development focus in recent years. However, the bidirectional device of the common-drain structure has a complex working state, and any source electrode or gate electrode may be in a high-voltage state in a certain working state, which may cause high voltage in the peripheral area of the chip and have reliability risks. SUMMARY

[0005] In view of this, in order to overcome the defects of the prior art, the purpose of the application is to provide a GaN bidirectional device containing a common gate structure, which can always obtain a low potential during the working process and ensure the reliability of the device and optimize the performance of the device.

[0006] In order to achieve the above purpose, the application adopts the following technical scheme:

[0007] A GaN bidirectional device with a common gate structure, comprising a substrate, a stack structure and a dielectric layer arranged in sequence from bottom to top, the substrate has a cutting channel above it, the cutting channel penetrates the thickness direction of the dielectric layer and the stack structure, the GaN bidirectional device further comprises a main body structure, a common gate structure and an outer ring structure, the outer ring structure is arranged around the inner circle of the cutting channel and surrounds the outside of the main body structure and the common gate structure, the main body structure comprises first main body units and second main body units arranged alternately in a first direction, the first main body unit comprises a first source electrode and a first gate structure arranged around the outside of the first source electrode, and the second main body unit comprises a second source electrode and a second gate structure arranged around the outside of the second source electrode; wherein the first direction is parallel to the length direction or the width direction of the substrate.

[0008] The common gate structure comprises two drain electrodes, two third source electrodes, two resistors, a third gate electrode and a third field plate, the third gate electrode is connected with the third field plate, the two resistors are connected in series and each third source electrode is connected with one resistor, the two drain electrodes are connected with one first source electrode and one second source electrode respectively, or the two drain electrodes are connected with one first gate structure and one second gate structure respectively;

[0009] The outer ring structure at least comprises an outer ring field plate, one connection node between the two series-connected resistors is set as a low potential end, and the low potential end is electrically connected with the outer ring field plate and / or the substrate.

[0010] By arranging the common gate structure in the GaN bidirectional device, the common gate structure comprises two drain electrodes, two third source electrodes, two resistors, a third gate electrode and a third field plate, the two drain electrodes share one third gate electrode and one third field plate, the two drain electrodes serve as two input ends of the common gate structure, the two third source electrodes do not have separate electrodes, but are connected with the end of the resistor formed by the two-dimensional electron gas respectively; a low potential end is led out at one connection node between the two series-connected resistors, and the low potential end is electrically connected with the outer ring structure and / or the substrate, so as to ensure that the GaN bidirectional device can always extract a low potential during operation, thereby improving the reliability of the device and optimizing the performance of the device.

[0011] According to some preferred embodiments of the present application, the resistors are located in the stacked structure, and the distance between the connection node of the low potential end and the two resistors is equal, so as to ensure that the outer ring structure and / or the substrate can stably maintain low voltage. In addition, in some embodiments of the present application, the stacked structure has a high concentration of two-dimensional electron gas, and the two-dimensional electron gas in the injection area is destroyed to form an electrically isolated region by performing a patterning process on the cap layer of the stacked structure and injecting ion materials, and the structure of the resistor is formed when the isolation is completed. Moreover, in the common gate structure of the present application, the two resistors are formed by taking the two ends of a long resistor formed by isolation as two electrodes, and taking an electrode (by setting a first connection part) at the middle point (low potential end) of the long resistor, so as to equivalently connect the entire long resistor as two series-connected resistors.

[0012] According to some preferred embodiments of the present application, one of the first main units and one of the second main units adjacent thereto has a common drain electrode, the first source electrode and the second source electrode are located on the side of the stacked structure away from the substrate, and the first gate structure and the second gate structure are located on the side of the dielectric layer away from the substrate.

[0013] The first gate structure comprises a first field plate and a first gate electrode located inside the first field plate, and the first field plate is connected with the first source electrode or the first gate electrode. The second gate structure comprises a second field plate and a second gate electrode located inside the second field plate, and the second field plate is connected with the second source electrode or the second gate electrode. In the present application, one of the first main units and one of the second main units adjacent thereto has a common drain electrode, that is, the first main unit and the second main unit share a common drain electrode, and the common drain electrode is not separately taken out as an electrode. The region where the main structure of the GaN bidirectional device of the present application is located constitutes the main functional area of the entire device.

[0014] According to some preferred embodiments of the present application, the outer ring structure is located on the side of the dielectric layer away from the substrate, and the outer ring structure further comprises a fourth gate electrode located outside the outer ring field plate, and the fourth gate electrode is connected with the outer ring field plate.

[0015] According to some preferred embodiments of the present application, the two drain electrodes are respectively connected with a first source electrode and a second source electrode.

[0016] According to some preferred embodiments of the present application, the two drain electrodes are respectively connected with a first gate electrode and a second gate electrode.

[0017] According to some preferred embodiments of the present application, the outer ring structure further comprises a first connecting portion and a second connecting portion, one side of the outer ring structure is provided with a notch downward from the top surface, the notch penetrates the thickness direction of the outer ring structure, the notch is communicated with the cutting channel, the notch is used for allowing the first connecting portion and the second connecting portion to pass through, the other part of the second connecting portion is located in the cutting channel, one end of the first connecting portion is connected with the low potential end, the other end of the first connecting portion is connected with one end of the second connecting portion, and the end of the second connecting portion away from the first connecting portion is connected with the substrate, so as to electrically connect the low potential end with the substrate. In some embodiments of the present application, the first connecting portion and the second connecting portion are both made of metal, and the mutual connection of the first connecting portion and the second connecting portion can electrically connect the low potential end with the substrate, so that the dynamic resistance of the device can be effectively reduced when the low potential end is connected with the substrate, and the reliability of the device can be improved.

[0018] According to some preferred embodiments of the present application, each end of the notch has a spacing between the side surface of the first connecting portion and the second connecting portion close to the end. The notch is thus arranged to further ensure that the first connecting portion and the second connecting portion are not connected with the outer ring field plate, so that the low potential end is only electrically connected with the substrate.

[0019] According to some preferred embodiments of the present application, the outer ring structure further comprises a first connecting portion, one end of the first connecting portion is connected with the low potential end, and the other end of the first connecting portion is connected with the outer ring field plate, so as to electrically connect the low potential end with the outer ring field plate. When the low potential end is connected with the outer ring field plate, the outer ring field plate can always be at a low potential, and the reliability of the device can be higher. In addition, the outer ring field plate connected with the low potential end can ensure that the terminal electric field of the first field plate and the second field plate of the main body structure is effectively controlled when the first field plate and the second field plate are at a high potential.

[0020] According to some preferred embodiments of the present application, the outer ring structure further comprises a third connecting portion, the bottom of the third connecting portion is located in the cutting channel, one end of the third connecting portion is connected with the substrate, and the other end of the third connecting portion is connected with the fourth gate electrode, so as to electrically connect the low potential end with the outer ring field plate and the substrate. In some embodiments of the present application, the third connecting portion is also made of metal. In the present application, the low potential end is connected with the outer ring field plate, and the third connecting portion is connected with the fourth gate electrode, and the fourth gate electrode is connected with the outer ring field plate, so that a connection is formed between the outer ring field plate and the conductive substrate, and the low potential end is electrically connected with the outer ring field plate and the substrate. When the low potential end is connected with the outer ring field plate and the substrate, the outer ring field plate of the device can be at the same potential as the substrate, and the reliability of the device can be further improved.

[0021] According to some preferred embodiments of the invention, all the first source electrodes are connected in parallel to form a first output interface, all the first gate electrodes are connected in parallel to form a second output interface, all the second source electrodes are connected in parallel to form a third output interface, and all the second gate electrodes are connected in parallel to form a fourth output interface.

[0022] Due to the adoption of the above technical solutions, compared with the prior art, the advantages of the present invention are as follows: The GaN bidirectional device with a common gate structure of the present invention, by setting a common gate structure and leading out a low potential end in the common gate structure, and the low potential end being connected to at least one of the outer ring structure and the substrate, can realize that the GaN bidirectional device can always extract a low potential during operation, which is beneficial to improving the reliability of the GaN bidirectional device and optimizing the device performance. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a top view of the GaN bidirectional device in Embodiment 1 of the present invention;

[0025] Figure 2 This is a top view of the GaN bidirectional device in Embodiment 2 of the present invention;

[0026] Figure 3 This is a top view of the GaN bidirectional device in Embodiment 3 of the present invention;

[0027] Figure 4 for Figure 1 A cross-sectional view of the structure along the direction of the dashed line A;

[0028] Figure 5 for Figure 1 A cross-sectional view of the structure along the direction of dashed line B;

[0029] Figure 6 for Figure 1 A cross-sectional view of the structure along the direction of dashed line C;

[0030] Figure 7 for Figure 2 A cross-sectional view of the structure along the direction of the dashed line D;

[0031] Figure 8 for Figure 3 A cross-sectional view of the structure along the direction of the dashed line E;

[0032] Figure 9 Equivalent circuit diagram of GaN bidirectional device in embodiment 1 of the present application;

[0033] Figure 10 Equivalent circuit diagram of GaN bidirectional device in embodiment 2 of the present application;

[0034] Figure 11 Equivalent circuit diagram of GaN bidirectional device in embodiment 3 of the present application;

[0035] In the drawings, reference numerals are as follows:

[0036] Substrate-1, nucleation layer-21, buffer layer-22, channel layer-23, barrier layer-24, cap layer-25, dielectric layer-3, dicing street-4, main structure-5, first source electrode-51, first gate electrode-52, first field plate-53, second source electrode-54, second gate electrode-55, second field plate-56, common drain electrode-57, common gate structure-6, drain electrode-61, third source electrode-62, resistor-63, third gate electrode-64, third field plate-65, low potential end-66, outer ring structure-7, outer ring field plate-71, fourth gate electrode-72, notch-73, first connecting part-81, second connecting part-82, third connecting part-83, metal connecting strip-84, first output interface-91, second output interface-92, third output interface-93, fourth output interface-94. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the scope of protection of the present application.

[0038] Embodiment 1: The present embodiment provides a GaN bidirectional device containing a common gate structure 6, as shown in Figure 1 , Figures 4 to 6As shown, the structure includes a main body structure 5, a common gate structure 6, an outer ring structure 7, and a substrate 1, a laminated structure, and a dielectric layer 3 arranged in order from bottom to top, and the substrate 1 has a cutting channel 4 above it, which penetrates the thickness direction of the dielectric layer 3 and the laminated structure. Among them, the outer ring structure 7 is arranged along the inner ring of the cutting channel 4 and surrounds the outside of the main body structure 5 and the common gate structure 6. Specifically, the laminated structure includes a nucleation layer 21, a buffer layer 22, a channel layer 23, a barrier layer 24, and a cap layer 25 arranged in order from bottom to top, and the heterojunction interface between the channel layer 23 and the barrier layer 24 has a two-dimensional electron gas.

[0039] Further, as shown, Figure 1 The main body structure 5 includes first main body units and second main body units arranged alternately along the length direction of the substrate 1, and one first main body unit and one second main body unit adjacent thereto have a common drain electrode 57, that is, the first main body unit and the second main body unit share a drain electrode, and the common drain electrode 57 does not have a separate electrode.

[0040] Specifically, the first main body unit includes a first source electrode 51 and a first gate structure arranged outside the first source electrode 51, and the second main body unit includes a second source electrode 54 and a second gate structure arranged outside the second source electrode 54; the first source electrode 51 and the second source electrode 54 are arranged on the side of the laminated structure away from the substrate 1, and the first source electrode 51 and the second source electrode 54 are both located in the barrier layer 24, the cap layer 25 and the dielectric layer 3. The first gate structure and the second gate structure are both arranged on the side of the dielectric layer 3 away from the substrate 1, wherein the first gate structure includes a first field plate 53 and a first gate electrode 52 located inside the first field plate 53, and the second gate structure includes a second field plate 56 and a second gate electrode 55 located inside the second field plate 56. In this embodiment, the first field plate 53 is connected with the first gate electrode 52, and the second field plate 56 is connected with the second gate electrode 55.

[0041] Further, as shown, Figure 1 The common gate structure 6 includes two drain electrodes 61, two third source electrodes 62, two resistors 63, one third gate electrode 64, and one third field plate 65, the third gate electrode 64 and the third field plate 65 are both arranged on the side of the dielectric layer 3 away from the substrate 1, the third source electrode 62 and the drain electrode 61 are both arranged on the side of the laminated structure away from the substrate 1, and the third source electrode 62 and the drain electrode 61 are both located in the barrier layer 24, the cap layer 25 and the dielectric layer 3; the resistor 63 is located in the laminated structure, specifically, by performing a patterning process on the cap layer 25 of the laminated structure and injecting ion materials, the two-dimensional electron gas of the injection area is destroyed to form an electrical isolation region, and the structure of the resistor 63 is formed during the isolation.

[0042] The third gate electrode 64 is connected with the third field plate 65. In the embodiment, two metal connecting strips 84 are further arranged between the common gate structure 6 and the main body structure 5. One of the drain electrodes 61 is connected with one of the first source electrodes 51 through one of the metal connecting strips 84, and the other of the drain electrodes 61 is connected with the second source electrode 54 through the other of the metal connecting strips 84. The length of one of the first source electrodes 51 corresponding to one of the first main body units and the length of one of the second source electrodes 54 corresponding to one of the second main body units are shorter than the lengths of the other first main body units and the other second main body units, so as to facilitate the arrangement of the common gate structure 6. In addition, the two resistors 63 are connected in series, and each of the third source electrodes 62 is connected with one end of one of the resistors 63. One of the connecting nodes between the two series-connected resistors 63 is set as the low potential end 66, and the distance between the connecting node set as the low potential end 66 and the two resistors 63 is equal.

[0043] Further, as shown in Figure 1 the outer ring structure 7 is also located on the side of the dielectric layer 3 away from the substrate 1. The outer ring structure 7 comprises an outer ring field plate 71 and a fourth gate electrode 72 located outside the outer ring field plate 71. The fourth gate electrode 72 is connected with the outer ring field plate 71. In the embodiment, a first connecting part 81 made of metal is arranged between the resistor 63 and the outer ring field plate 71. One end of the first connecting part 81 is connected with the low potential end 66, and the other end of the first connecting part 81 is connected with the outer ring field plate 71, so as to electrically connect the low potential end 66 with the outer ring field plate 71.

[0044] The equivalent circuit diagram of the GaN bidirectional device of the embodiment is shown in Figure 9 which, all of the first source electrodes 51 are connected in parallel to form a first output interface 91, all of the first gate electrodes 52 are connected in parallel to form a second output interface 92, all of the second source electrodes 54 are connected in parallel to form a third output interface 93, and all of the second gate electrodes 55 are connected in parallel to form a fourth output interface 94. The two third source electrodes 62 of the common gate structure 6 are electrically connected with one corresponding resistor 63 respectively, the two drain electrodes 61 of the common gate structure 6 are electrically connected with one first source electrode 51 and one second source electrode 54 respectively, the common gate structure 6 shares one third gate electrode 64 and one third field plate 65, and the common gate structure 6 has the low potential end 66 which is electrically connected with the outer ring field plate 71. In the embodiment, when the low potential end 66 is connected with the outer ring field plate 71, the outer ring field plate 71 can always be at a low potential, which can effectively improve the reliability of the device. In addition, the outer ring field plate 71 connected with the low potential end 66 can ensure that the terminal electric field of the first field plate 53 and the second field plate 56 of the main body structure 5 is effectively controlled when the first field plate 53 and the second field plate 56 are at a high potential, which is conducive to optimizing the performance of the device.

[0045] Embodiment 2: The embodiment provides a GaN bidirectional device containing a common gate structure 6, as shown in the figure. Figure 2 and Figure 7 As shown in the figure, the common gate structure 6 includes a main body structure 5, a common gate structure 6, an outer ring structure 7, and a substrate 1, a laminated structure and a dielectric layer 3 arranged in order from bottom to top, and the substrate 1 has a cutting channel 4 above it, which penetrates the thickness direction of the dielectric layer 3 and the laminated structure. Among them, the outer ring structure 7 is arranged along the inner ring of the cutting channel 4 and surrounds the outside of the main body structure 5 and the common gate structure 6. Specifically, the laminated structure includes a nucleation layer 21, a buffer layer 22, a channel layer 23, a barrier layer 24 and a cap layer 25 arranged in order from bottom to top, and the heterojunction interface between the channel layer 23 and the barrier layer 24 has a two-dimensional electron gas.

[0046] Further, as shown in the figure, Figure 2 The main body structure 5 includes first main body units and second main body units arranged alternately along the length direction of the substrate 1, and a common drain electrode 57 is provided between one first main body unit and one second main body unit adjacent thereto, that is, the first main body unit and the second main body unit share a drain electrode, and the common drain electrode 57 does not separately lead out an electrode.

[0047] Specifically, the first main body unit includes a first source electrode 51 and a first gate structure arranged outside the first source electrode 51, and the second main body unit includes a second source electrode 54 and a second gate structure arranged outside the second source electrode 54; the first source electrode 51 and the second source electrode 54 are arranged on the side of the laminated structure away from the substrate 1, and the first source electrode 51 and the second source electrode 54 are both located in the barrier layer 24, the cap layer 25 and the dielectric layer 3. The first gate structure and the second gate structure are both arranged on the side of the dielectric layer 3 away from the substrate 1, wherein the first gate structure includes a first field plate 53 and a first gate electrode 52 located inside the first field plate 53, and the second gate structure includes a second field plate 56 and a second gate electrode 55 located inside the second field plate 56, and the first field plate 53 and the first gate electrode 52 are connected in the embodiment, and the second field plate 56 and the second gate electrode 55 are connected.

[0048] Further, as shown in the figure, Figure 2 The common gate structure 6 includes two drain electrodes 61, two third source electrodes 62, two resistors 63, one third gate electrode 64 and one third field plate 65, the third gate electrode 64 and the third field plate 65 are both arranged on the side of the dielectric layer 3 away from the substrate 1, the third source electrode 62 and the drain electrode 61 are both arranged on the side of the laminated structure away from the substrate 1, and the third source electrode 62 and the drain electrode 61 are both located in the barrier layer 24, the cap layer 25 and the dielectric layer 3; the resistor 63 is located in the laminated structure, specifically, by performing a patterning process on the cap layer 25 of the laminated structure and implanting ion materials, the two-dimensional electron gas of the implanted area is destroyed to form an electrical isolation region, and the structure of the resistor 63 is formed during isolation.

[0049] The third gate electrode 64 is connected with the third field plate 65. In the embodiment, two metal connecting strips 84 are further arranged between the common gate structure 6 and the main body structure 5. One of the drain electrodes 61 is connected with one of the first source electrodes 51 through one of the metal connecting strips 84, and the other of the drain electrodes 61 is connected with the second source electrode 54 through the other of the metal connecting strips 84. The length of one of the first source electrodes 51 corresponding to one of the first main body units and the length of the second source electrode 54 corresponding to one of the second main body units are shorter than the lengths of the other first main body units and the other second main body units, so as to facilitate the arrangement of the common gate structure 6. In addition, the two resistors 63 are connected in series, and each of the third source electrodes 62 is connected with one end of one of the resistors 63. One of the connecting nodes between the two series-connected resistors 63 is set as the low potential end 66, and the distance between the connecting node set as the low potential end 66 and the two resistors 63 is equal.

[0050] Further, as shown in FIG. 7, the outer ring structure 7 is also located on the side of the dielectric layer 3 away from the substrate 1. The outer ring structure 7 comprises an outer ring field plate 71 and a fourth gate electrode 72 located outside the outer ring field plate 71. The fourth gate electrode 72 is connected with the outer ring field plate 71. In the embodiment, one side edge of the outer ring structure 7 corresponding to the position of the common gate structure 6 is provided with a notch 73 downward from the top surface thereof, which is in communication with the cutting channel 4 and penetrates the thickness direction of the outer ring structure 7. The notch 73 is used to disconnect the position of the outer ring structure 7 corresponding to the common gate structure 6. Figure 2 In the embodiment, the first connecting part 81 and the second connecting part 82 made of metal are arranged at the positions of the resistors 63 close to the notch 73. The notch 73 is used for the first connecting part 81 and the second connecting part 82 to pass through, and the other part of the second connecting part 82 is located in the cutting channel 4. In addition, each end of the notch 73 has a spacing with the side surface of the first connecting part 81 and the second connecting part 82 close thereto, so as to ensure that the first connecting part 81 and the second connecting part 82 are not connected with the outer ring structure 7. Specifically, one end of the first connecting part 81 is connected with the low potential end 66, the other end of the first connecting part 81 is connected with one end of the second connecting part 82, and the end of the second connecting part 82 away from the first connecting part 81 is connected with the substrate 1, so as to electrically connect the low potential end 66 with the substrate 1.

[0051] The equivalent circuit diagram of the GaN bidirectional device of the embodiment is shown in FIG. 8.

[0052] Figure 10 ​As shown, all the first source electrodes 51 are connected in parallel to form a first output interface 91, all the first gate electrodes 52 are connected in parallel to form a second output interface 92, all the second source electrodes 54 are connected in parallel to form a third output interface 93, and all the second gate electrodes 55 are connected in parallel to form a fourth output interface 94. The two third source electrodes 62 of the common gate structure 6 are electrically connected to a corresponding resistor 63, and the two drain electrodes 61 of the common gate structure 6 are electrically connected to a first source electrode 51 and a second source electrode 54, respectively. The common gate structure 6 shares a third gate electrode 64 and a third field plate 65. The common gate structure 6 has a low potential terminal 66 and the low potential terminal 66 is electrically connected to the substrate 1, which can effectively reduce the dynamic resistance of the device and thus help improve the reliability of the device.

[0053] Example 3: This example provides a GaN bidirectional device containing a common-gate structure 6, such as... Figure 3 and 8 As shown in the figure, the structure includes a main structure 5, a common gate structure 6, an outer ring structure 7, and a substrate 1, a stacked structure, and a dielectric layer 3 arranged sequentially from bottom to top. A dicing channel 4 is located above the substrate 1, penetrating the thickness direction of the dielectric layer 3 and the stacked structure. The outer ring structure 7 is arranged around the inner circle of the dicing channel 4 and surrounds the main structure 5 and the common gate structure 6. Specifically, the stacked structure includes a nucleation layer 21, a buffer layer 22, a channel layer 23, a barrier layer 24, and a capping layer 25 arranged sequentially from bottom to top. The heterojunction interface between the channel layer 23 and the barrier layer 24 has a two-dimensional electron gas.

[0054] Furthermore, such as Figure 3 As shown, the main structure 5 includes a first main unit and a second main unit arranged alternately along the length direction of the substrate 1. A first main unit and an adjacent second main unit have a common drain electrode 57, that is, the first main unit and the second main unit share a common drain electrode, and the common drain electrode 57 does not have a separate electrode.

[0055] Specifically, the first main body unit includes a first source electrode 51 and a first gate structure surrounding the first source electrode 51, and the second main body unit includes a second source electrode 54 and a second gate structure surrounding the second source electrode 54. The first source electrode 51 and the second source electrode 54 are disposed on the side of the stacked structure away from the substrate 1, and both the first source electrode 51 and the second source electrode 54 are located in the barrier layer 24, the capping layer 25, and the dielectric layer 3. The first gate structure and the second gate structure are both disposed on the side of the dielectric layer 3 away from the substrate 1. The first gate structure includes a first field plate 53 and a first gate electrode 52 located inside the first field plate 53, and the second gate structure includes a second field plate 56 and a second gate electrode 55 located inside the second field plate 56. In this embodiment, the first field plate 53 is connected to the first gate electrode 52, and the second field plate 56 is connected to the second gate electrode 55.

[0056] Furthermore, such as Figure 3 As shown, the common gate structure 6 includes two drain electrodes 61, two third source electrodes 62, two resistors 63, a third gate electrode 64, and a third field plate 65. The third gate electrode 64 and the third field plate 65 are both disposed on the side of the dielectric layer 3 away from the substrate 1. The third source electrode 62 and the drain electrode 61 are both disposed on the side of the stacked structure away from the substrate 1, and the third source electrode 62 and the drain electrode 61 are both located in the barrier layer 24, the capping layer 25, and the dielectric layer 3. The resistor 63 is located in the stacked structure. Specifically, by patterning and implanting ion material above the capping layer 25 of the stacked structure, the two-dimensional electron gas in the implanted region is destroyed to form an electrically isolated region, and the structure of resistor 63 is formed during isolation.

[0057] The third gate electrode 64 is connected to the third field plate 65. In this embodiment, two metal connecting strips 84 are also provided between the common gate structure 6 and the main body structure 5. One drain electrode 61 is connected to a first source electrode 51 through one metal connecting strip 84, and the other drain electrode 61 is connected to a second source electrode 54 through another metal connecting strip 84. The length of the first main body unit corresponding to one first source electrode 51 connected to the two drain electrodes 61 in the common gate structure 6 and the length of the second main body unit corresponding to one second source electrode 54 are shorter than the lengths of the other first and second main body units, to facilitate the configuration of the common gate structure 6. Furthermore, two resistors 63 are connected in series, and each third source electrode 62 is connected to one end of one resistor 63. A connection node between the two series-connected resistors 63 is set as a low-potential terminal 66, and the distance from the connection node set as the low-potential terminal 66 to the two resistors 63 is equal.

[0058] Furthermore, such as Figure 3As shown, the outer ring structure 7 is also located on the side of the dielectric layer 3 away from the substrate 1, and the outer ring structure 7 includes an outer ring field plate 71 and a fourth gate electrode 72 located outside the outer ring field plate 71, and the fourth gate electrode 72 is connected with the outer ring field plate 71. In the embodiment, a first connecting part 81 made of metal is arranged between the resistor 63 and the outer ring field plate 71, one end of the first connecting part 81 is connected with the low potential end 66, and the other end of the first connecting part 81 is connected with the outer ring field plate 71; and a third connecting part 83 made of metal is also arranged below the side of the outer ring structure 7, the bottom of the third connecting part 83 is located in the cutting path 4, one end of the third connecting part 83 is connected with the substrate 1, and the other end of the third connecting part 83 is connected with the fourth gate electrode 72. In the embodiment, through the arrangement of the first connecting part 81 and the third connecting part 83, the low potential end 66 is electrically connected with the outer ring field plate 71 and the substrate 1 at the same time.

[0059] The equivalent circuit diagram of the GaN bidirectional device of the embodiment is shown in Figure 11 As shown, all the first source electrodes 51 are connected in parallel to form a first output interface 91, all the first gate electrodes 52 are connected in parallel to form a second output interface 92, all the second source electrodes 54 are connected in parallel to form a third output interface 93, and all the second gate electrodes 55 are connected in parallel to form a fourth output interface 94; two third source electrodes 62 of the common gate structure 6 are respectively electrically connected with a corresponding resistor 63, two drain electrodes 61 of the common gate structure 6 are respectively electrically connected with a first source electrode 51 and a second source electrode 54, the common gate structure 6 shares a third gate electrode 64 and a third field plate 65, the common gate structure 6 has a low potential end 66 which is electrically connected with the outer ring field plate 71 and the substrate 1 at the same time, which can ensure that the outer ring field plate 71 and the substrate 1 of the device are at the same potential, and further improve the reliability of the device.

[0060] In some other embodiments of the present application, compared with the embodiments 1, 2 and 3, one drain electrode 61 in the common gate structure 6 can be connected with a first gate electrode 52 in the main body structure 5 through a metal connecting strip 84, and the other drain electrode 61 is connected with a second gate electrode 55 through another metal connecting strip 84, and other structures remain unchanged, and the technical solutions of electrically connecting the low potential end 66 with the outer ring field plate 71, electrically connecting the low potential end 66 with the substrate 1, and electrically connecting the low potential end 66 with the outer ring field plate 71 and the substrate 1 at the same time can also be realized.

[0061] The GaN bidirectional device in the application can always extract low potential in the working process by setting the common gate structure 6 and leading out the low potential end 66 in the common gate structure 6, and the low potential end 66 is connected with at least one of the outer ring structure 7 and the substrate 1, thereby effectively improving the reliability of the GaN bidirectional device.

[0062] The above embodiments of the application are only for illustrating the technical concept and characteristics of the application, and the purpose is to enable those skilled in the art to understand the content of the application and implement it, and cannot limit the protection scope of the application. Any equivalent changes or modifications made according to the spirit and essence of the application shall be covered within the protection scope of the application.

Claims

1. A GaN bidirectional device containing a common gate structure, comprising a substrate, a stack structure and a dielectric layer arranged in order from bottom to top, the substrate has a dicing lane above, the dicing lane penetrates through the thickness direction of the dielectric layer and the stack structure, characterized in that, The GaN bidirectional device further comprises a main body structure, a common gate structure and an outer ring structure, the outer ring structure is arranged in a ring along an inner circle of a scribe lane and surrounds outside the main body structure and the common gate structure, the main body structure comprises first main body units and second main body units arranged alternately in a first direction, the first main body unit comprises a first source electrode and a first gate structure arranged outside the first source electrode, and the second main body unit comprises a second source electrode and a second gate structure arranged outside the second source electrode, the first direction is parallel to a length direction or a width direction of the substrate; The common gate structure comprises two drain electrodes, two third source electrodes, two resistors, a third gate electrode and a third field plate, the third gate electrode is connected with the third field plate, the two resistors are connected in series, and each third source electrode is connected with one resistor, the two drain electrodes are connected with one first source electrode and one second source electrode respectively, or the two drain electrodes are connected with one first gate structure and one second gate structure respectively; The outer ring structure comprises at least an outer ring field plate, and a connection node between the two series-connected resistors is arranged as a low potential end, the low potential end is electrically connected with the outer ring field plate and / or the substrate.

2. The GaN diode device of claim 1, wherein, The resistors are located in a laminated structure, and the distance from the connection node arranged as the low potential end to the two resistors is equal.

3. The GaN diode device of claim 2, wherein, One of the first main body units and one of the second main body units adjacent to each other have a common drain electrode, the first source electrode and the second source electrode are located on a side of the laminated structure away from the substrate, and the first gate structure and the second gate structure are located on a side of the dielectric layer away from the substrate. The first gate structure comprises a first field plate and a first gate electrode located inside the first field plate, the first field plate is connected with the first source electrode or the first gate electrode, and the second gate structure comprises a second field plate and a second gate electrode located inside the second field plate, the second field plate is connected with the second source electrode or the second gate electrode.

4. The GaN bi-directional device of claim 3, wherein, The outer ring structure is located on a side of the dielectric layer away from the substrate, and the outer ring structure further comprises a fourth gate electrode located outside the outer ring field plate, and the fourth gate electrode is connected with the outer ring field plate.

5. The GaN diode device of claim 4, wherein, The two drain electrodes are connected with one first source electrode and one second source electrode respectively.

6. The GaN diode device of claim 4, wherein, The two drain electrodes are connected with one first gate electrode and one second gate electrode respectively.

7. The GaN diode device of claim 5 or 6, wherein, Further comprising a first connecting part and a second connecting part, one side edge of the outer ring structure is provided with a notch downward from a top surface of the outer ring structure, the notch penetrates through a thickness direction of the outer ring structure, the notch is communicated with the scribe lane, the notch is used for allowing part of the first connecting part and part of the second connecting part to pass through, another part of the second connecting part is located in the scribe lane, one end of the first connecting part is connected with the low potential end, the other end of the first connecting part is connected with one end of the second connecting part, and the end of the second connecting part away from the first connecting part is connected with the substrate, so as to electrically connect the low potential end with the substrate.

8. The GaN diode device of claim 7, wherein, Each end of the notch has a spacing between a side surface of the first connecting part and the second connecting part close to the end.

9. The GaN diode device of claim 5 or 6, wherein, The first connecting part has one end connected with the low potential end and the other end connected with the outer ring field plate, so as to electrically connect the low potential end with the outer ring field plate.

10. The GaN diode device of claim 9, wherein, The third connecting part has a bottom located in the cutting path, one end connected with the substrate and the other end connected with the fourth gate electrode, so as to electrically connect the low potential end with the outer ring field plate and the substrate.

11. The GaN diode device of claim 3, wherein, All the first source electrodes are connected in parallel to form a first output interface, all the first gate electrodes are connected in parallel to form a second output interface, all the second source electrodes are connected in parallel to form a third output interface, and all the second gate electrodes are connected in parallel to form a fourth output interface.

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