A gallium nitride bidirectional switching device and a method of fabricating the same

Abstract

The application relates to the technical field of semiconductors, in particular to a gallium nitride bidirectional switch device and a preparation method thereof. The first cell structure and the second cell structure of the gallium nitride bidirectional switch device are compared with the existing discrete gallium nitride power device and Si power device, the source electrode and the gate electrode of the discrete gallium nitride power device are shared, the specific on-resistance of the device is significantly reduced, the area of the chip is effectively reduced, and the cost of the chip is reduced. The source metal electrode is introduced, the field plate of the bidirectional switch device and the substrate of the bidirectional switch device are electrically connected with the source electrode of the bidirectional switch device, the robustness of the bidirectional switch device is effectively improved, and the bidirectional switch device is easy to drive and control.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a gallium nitride bidirectional switch device and a preparation method thereof. Background Art

[0002] Bidirectional switching devices have important applications in AC-AC conversion, three-phase rectification / inversion, and microinverters. Traditionally, Si-based power devices require four discrete devices in a "two-in-series, two-in-parallel" configuration to achieve the functionality of a bidirectional switch, increasing system cost and complexity. Gallium nitride, a third-generation semiconductor material, boasts wide bandgap and high mobility, enabling higher switching frequencies and power densities. Furthermore, GaN devices utilize a lateral device structure, enabling better integrated designs. Multiple discrete Si-based power devices can be replaced with a single monolithic integrated GaN bidirectional switch.

[0003] like Figure 1~Figure 2 As shown, a monolithically integrated common-source GaN bidirectional switch device is equivalent to shorting the sources of two discrete GaN devices together. This common-source GaN bidirectional switch device is simple to control, requiring only one isolated drive circuit and no substrate control; the substrate can be directly connected to the source. However, common-source GaN bidirectional switches have drawbacks. The active area of ​​a common-source GaN bidirectional switch device cannot be significantly reduced compared to the area of ​​multiple discrete Si-based power devices. Therefore, reducing the active area of ​​the common-source GaN bidirectional switch device and optimizing the device's Ron,sp (specific on-resistance) to reduce chip cost are technical challenges that urgently need to be addressed. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a gallium nitride bidirectional switch device and a preparation method thereof.

[0005] To achieve the above objectives, the present invention provides a gallium nitride bidirectional switch device, comprising:

[0006] comprising a first cellular structure and a second cellular structure, wherein the second cellular structure and the first cellular structure are arranged in parallel;

[0007] The first cell structure includes: a substrate, a buffer layer located on the surface of the substrate, and a barrier layer located on the surface of the buffer layer; a first drain and a second drain, the first drain and the second drain being located on the surface of the barrier layer and spaced apart; a first gate, the first gate being located on the surface of the barrier layer and disposed between the first drain and the second drain; a dielectric layer, the dielectric layer being located on the surface of the barrier layer, the first gate, the first drain, and the second drain; a source metal electrode located on the surface of the dielectric layer; a first field plate structure and a second field plate structure, the first field plate structure and the second field plate structure being located in the dielectric layer and the first field plate structure being located between the first gate and the first drain, the second field plate structure being located between the first gate and the second drain, the first field plate structure and the second field plate structure being connected to the source metal electrode, so that the first field plate structure and the second field plate structure apply a source voltage to the barrier layer;

[0008] The second cellular structure includes: a substrate, a buffer layer located on the surface of the substrate, and a barrier layer located on the surface of the buffer layer; a third drain, a fourth drain, a second gate, a third gate and a source located on the surface of the barrier layer, the source being located between the third drain and the fourth drain, the second gate being located between the third drain and the source, and the third gate being located between the fourth drain and the source; a dielectric layer, the dielectric layer being located on the surfaces of the barrier layer, the third drain, the fourth drain, the second gate, the third gate and the source; and a source metal electrode located on the surface of the dielectric layer, the source metal electrode being connected to the source.

[0009] Optionally, the second cell structure further includes: a third field plate structure and a fourth field plate structure located in the dielectric layer, the third field plate structure being located between the second gate and the third drain, the fourth field plate structure being located between the second gate and the fourth drain, and the third field plate structure and the fourth field plate structure being connected to the source metal electrode.

[0010] Optionally, the first field plate structure to the fourth field plate structure all include single-layer field plates or multi-layer field plates.

[0011] Optionally, it includes at least one of the first cellular structures and at least one of the second cellular structures.

[0012] Optionally, the gate width of the second cellular structure is equal to the gate width of the first cellular structure, or the gate width of the second cellular structure is not equal to the gate width of the first cellular structure.

[0013] Optionally, the second cellular structure and the first cellular structure are arranged in parallel, and the adjacent second cellular structure and the first cellular structure, or the second cellular structure and the second cellular structure, or the first cellular structure and the first cellular structure share a drain.

[0014] Optionally, the second cellular structure and the first cellular structure are arranged in parallel and the adjacent active areas of the second cellular structure and the first cellular structure, or the active areas of the second cellular structure and the second cellular structure, or the active areas of the first cellular structure and the first cellular structure are separated.

[0015] Optionally, the second cellular structure and the first cellular structure are prepared on the same process platform.

[0016] The present invention also provides a method for preparing a gallium nitride bidirectional switch device, which is characterized by comprising:

[0017] Providing a substrate, the substrate comprising a first cellular structure region and a second cellular structure region;

[0018] forming a buffer layer on the surface of the substrate, and forming a barrier layer on the surface of the buffer layer;

[0019] A first drain, a second drain, and a first gate are formed on the surface of the barrier layer and in the first cellular structure region, and a third drain, a fourth drain, a second gate, a third gate, and a source are formed in the second cellular structure region; the first drain and the second drain are spaced apart, the first gate is disposed between the first drain and the second drain, the source is located between the third drain and the fourth drain, the second gate is located between the third drain and the source, and the third gate is located between the fourth drain and the source;

[0020] A dielectric layer is formed on the surfaces of the barrier layer, the first gate, the first drain, the second drain, the third drain, the fourth drain, the second gate, the third gate, and the source, and a first field plate structure and a second field plate structure are formed in the dielectric layer, the first field plate structure is located between the first gate and the first drain, and the second field plate structure is located between the first gate and the second drain;

[0021] A source metal electrode is formed on the surface of the dielectric layer and in the first cellular structure region and the second cellular structure region. The source metal electrode is connected to the source. The source metal electrode in the first cellular structure region is connected to the first field plate structure and the second field plate structure.

[0022] Optionally, a third field plate structure and a fourth field plate structure are formed in the dielectric layer, the third field plate structure is located between the second gate and the third drain, and the fourth field plate structure is located between the second gate and the fourth drain, and the third field plate structure and the fourth field plate structure are both connected to the source metal electrode in the second cell structure region.

[0023] In summary, the advantages and beneficial effects of the present invention are:

[0024] The present invention provides a gallium nitride bidirectional switch device and a preparation method thereof. The gallium nitride bidirectional switch device comprises: a first cellular structure and a second cellular structure, wherein the second cellular structure and the first cellular structure are arranged in parallel; the first cellular structure comprises: a substrate, a buffer layer located on the surface of the substrate, and a barrier layer located on the surface of the buffer layer; a first drain and a second drain, wherein the first drain and the second drain are located on the surface of the barrier layer and are spaced apart; a first gate, wherein the first gate is located on the surface of the barrier layer and is arranged between the first drain and the second drain; a dielectric layer, wherein the dielectric layer is located on the surface of the barrier layer, the first gate, the first drain and the second drain; a source metal electrode located on the surface of the dielectric layer; a first field plate structure and a second field plate structure, wherein the first field plate structure and the second field plate structure are located in the dielectric layer and the first field plate structure is located between the first gate and the first drain, and the second field plate structure Located between the first gate and the second drain, the first field plate structure and the second field plate structure are both connected to the source metal electrode, so that the first field plate structure and the second field plate structure apply a source voltage to the barrier layer; the second cellular structure includes: a substrate, a buffer layer located on the surface of the substrate, and a barrier layer located on the surface of the buffer layer; a third drain, a fourth drain, a second gate, a third gate and a source located on the surface of the barrier layer, the source is located between the third drain and the fourth drain, the second gate is located between the third drain and the source, and the third gate is located between the fourth drain and the source; a dielectric layer, the dielectric layer is located on the surfaces of the barrier layer, the third drain, the fourth drain, the second gate, the third gate and the source; a source metal electrode located on the surface of the dielectric layer, the source metal electrode is connected to the source.

[0025] Compared with existing discrete GaN power devices and Si power devices, by sharing the source and gate of discrete GaN power devices, the specific on-resistance of the obtained GaN power devices is significantly reduced, which effectively reduces the area of ​​the formed chip and thus reduces the chip cost.

[0026] The present invention introduces a source metal electrode, electrically connecting the field plate and the substrate of the bidirectional switch device to the source of the bidirectional switch device, effectively improving the robustness of the bidirectional switch device. In addition, the gallium nitride bidirectional switch device obtained by using the cellular structure of the gallium nitride bidirectional switch device only requires one drive circuit for control, thereby reducing the driving cost of the gallium nitride bidirectional switch device and thus reducing the cost of the gallium nitride bidirectional switch device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of a discrete GaN power device;

[0028] Figure 2 Schematic diagram of a common-source gallium nitride bidirectional switch device;

[0029] Figure 3 A schematic diagram of a gallium nitride bidirectional switch device provided in an embodiment of the present invention;

[0030] Figure 4 A schematic cross-sectional view of a first cell structure of a gallium nitride bidirectional switch device provided by an embodiment of the present invention;

[0031] Figure 5 A schematic cross-sectional view of a second cell structure of a gallium nitride bidirectional switch device provided by an embodiment of the present invention;

[0032] Figure 6 A schematic diagram of a perspective top view of a gallium nitride bidirectional switch device provided by an embodiment of the present invention;

[0033] Figure 7 A schematic diagram of a partially enlarged top view of a gallium nitride bidirectional switch device provided by an embodiment of the present invention;

[0034] Figure 8 A schematic diagram of an AA cross section of a gallium nitride bidirectional switch device provided by an embodiment of the present invention;

[0035] Figure 9 A schematic diagram of a BB cross-section of a gallium nitride bidirectional switch device provided by an embodiment of the present invention;

[0036] Figures 10 to 12 A schematic diagram of a gallium nitride bidirectional switch device provided in another embodiment of the present invention;

[0037] Figure 13 A schematic flow chart of a method for preparing a gallium nitride bidirectional device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] Power device performance is typically evaluated using the specific on-resistance (Ron,sp) = Ron*Area = Ron,pitch (Ω.mm)*Lpitch (mm). Ron,pitch is the on-resistance of a power device with a gate width of 1mm, and Lpitch is the lateral size of the GaN power device. Lpitch is one of the factors affecting Ron,pitch; the smaller Lpitch, the smaller Ron,pitch. Therefore, reducing the lateral size Lpitch of GaN power devices yields benefits in both on-resistance and chip area.

[0039] like Figure 1 As shown, the discrete GaN power device includes a source 10, a gate 30, and a drain 20. The lateral dimension of the discrete GaN power device is Lpitch=1 / 2*Ls+1 / 2*Ld+Lg+Lgs+Lgd, wherein Lpitch is the lateral dimension of the discrete GaN power device, Ls is the lateral dimension of the source 10, Ld is the lateral dimension of the drain 20, Lg is the lateral dimension of the gate 30, Lgs is the lateral dimension between the gate 30 and the source 10, and Lgd is the lateral dimension between the gate 30 and the drain 20.

[0040] like Figure 2 As shown, a discrete common-source GaN bidirectional switch device includes a source 10, two gates 30, and two drains 20. The lateral dimension Lpitch of the common-source GaN bidirectional switch device is Ls+Ld+2*Lg+2*Lgs+2*Lgd, where Ls is the lateral dimension of the source 10, Ld is the lateral dimension of the drain 20, Lg is the lateral dimension of the gate 30, Lgs is the lateral dimension between the gate 30 and the source 10, and Lgd is the lateral dimension between the gate 30 and the drain 20. The active area of ​​the discrete common-source GaN bidirectional switch device has no advantage over that of discrete GaN power devices or discrete Si-based power devices. The only advantage is the reduction in the area of ​​the overall chip and package formed based on the common-source GaN bidirectional switch device. Therefore, to reduce the active area of ​​the common-source GaN bidirectional switch device and optimize the device Ron,sp, the present invention provides a GaN bidirectional switch device and a preparation method thereof.

[0041] The following will describe the embodiments of the present invention in detail with reference to the accompanying drawings and examples, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve corresponding technical effects can be fully understood and implemented accordingly. The embodiments of the present invention and the various features therein can be combined with each other without conflict, and the resulting technical solutions are all within the scope of protection of the present invention. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0042] It should be understood that although the terms "first", "second", "third", etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part. Spatial relationship terms such as "above...", "above...", "below...", "below...", etc., may be used here for convenience of description to describe the relationship between an element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatial relationship terms are intended to also include different orientations of the device in use and operation.

[0043] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and are not to be construed as limiting the present invention.

[0044] The present invention provides a gallium nitride bidirectional switch device, such as Figure 3 Shown, including:

[0045] A substrate 111, a buffer layer 112 located on a surface of the substrate, and a barrier layer 113 located on a surface of the buffer layer;

[0046] A first drain electrode 201, a second drain electrode 202, and a first gate electrode 301 are located on the surface of the barrier layer, wherein the first drain electrode 201 and the second drain electrode 202 are spaced apart, and the first gate electrode 301 is located between the first drain electrode 201 and the second drain electrode 202;

[0047] a dielectric layer 80 , the dielectric layer 80 being located on surfaces of the barrier layer 13 , the first drain electrode 201 , the second drain electrode 202 , and the first gate electrode 301 ;

[0048] a first field plate structure 501 and a second field plate structure 502 located in the dielectric layer, wherein the first field plate structure 501 is located between the first gate 301 and the first drain 201 , and the second field plate structure 502 is located between the first gate 301 and the second drain 202 ;

[0049] A gate metal electrode 90 is located on the surface of the dielectric layer 80 , and the gate metal electrode 90 is connected to the first field plate structure 501 and the second field plate structure 502 .

[0050] Specifically, in the embodiment of the present invention, the lateral dimension Lpitch of the gallium nitride bidirectional switch device is Ld+Lg+2Lgd, wherein the distance between the first gate 301 and the first drain 201 is equal to the distance between the second drain 202. Figure 2 In comparison, the lateral dimensions of the gallium nitride bidirectional switch device are significantly reduced. If calculated based on the dimensions of a typical 650V power device, the area can be reduced by approximately 13%, and the specific on-resistance Ron,sp of the power device is reduced by approximately 27%. That is, the active area of ​​the chip with the same on-resistance is reduced by approximately 27%.

[0051] Although the GaN bidirectional switch device has significantly reduced chip area and specific on-resistance Ron,sp, it lacks a source. Therefore, the drive of the first gate 301 cannot reference the voltage of the grounded source like conventional GaN devices. This results in the first gate 301 having no reference ground, and thus, the first gate 301 cannot be normally turned on. If the first gate 301 references the voltage of the first drain 201 or the second drain 202, a high-voltage isolation drive must be provided. However, the design of the high-voltage isolation drive circuit is complex, resulting in increased cost and increased safety of the GaN bidirectional switch device. Furthermore, the field plates of the GaN bidirectional switch device, namely the first field plate structure 501 and the first field plate structure 502, can only be connected to the first gate 301 to form a gate field plate structure. This gate field plate structure increases the parasitic capacitance Cgd between the gate and drain of the GaN bidirectional switch device. A larger parasitic capacitance Cgd between the gate and drain increases the Miller ratio (i.e., the parasitic capacitance Cgd between the gate and drain) of the GaN power bidirectional switch device. This increases the risk of the GaN bidirectional switch device being falsely turned on under high dv / dt conditions. Therefore, to address the above technical issues, the present invention provides a GaN bidirectional switch device and a method for preparing the same.

[0052] The present invention also provides a gallium nitride bidirectional switch device, such as Figure 4~Figure 5 As shown, it includes: a first cellular structure cell1 and a second cellular structure cell2, wherein the first cellular structure cell1 and the second cellular structure cell2 are arranged in parallel;

[0053] The first cell structure cell1 includes: a substrate 111, a buffer layer 112 located on the surface of the substrate 111, a barrier layer 113 located on the surface of the buffer layer 112; a first drain 201 and a second drain 202, the first drain 201 and the second drain 202 being located on the surface of the barrier layer 113 and spaced apart; a first gate 301, the first gate 301 being located on the surface of the barrier layer 111 and being disposed between the first drain 201 and the second drain 202; a dielectric layer 80, the dielectric layer 80 being located on the surface of the barrier layer 113, the first gate 301, the first drain 201, and the second drain 202. a source metal electrode 101 located on the surface of the dielectric layer 80; a first field plate structure 501 and a second field plate structure 502, wherein the first field plate structure 501 and the second field plate structure 502 are located in the dielectric layer 80 and the first field plate structure 501 is located between the first gate 301 and the first drain 201, and the second field plate structure 502 is located between the first gate 301 and the second drain 202, and the first field plate structure 501 and the second field plate structure 502 are both connected to the source metal electrode 101, so that the first field plate structure 501 and the second field plate structure 502 apply a source voltage to the barrier layer 113;

[0054] The second cell structure cell2 includes: a substrate 111, a buffer layer 112 located on the surface of the substrate 111, a barrier layer 113 located on the surface of the buffer layer 112; a third drain 203, a fourth drain 204, a second gate 302, a third gate 303 and a source 10 located on the surface of the barrier layer 113, the source 10 being located between the third drain 203 and the fourth drain 204, the second gate 302 being located between the third drain 203 and the source 10, and the third gate 303 being located between the fourth drain 204 and the source 10; a dielectric layer 80, the dielectric layer 80 being located between the barrier layer 113, the third drain 203, the second gate 302 and the third gate 303 The surfaces of the four drains 204, the second gate 302, the third gate 303 and the source 10; the source metal electrode 102 located on the surface of the dielectric layer 80, the source metal electrode 102 being connected to the source 10; the third field plate structure 503 and the fourth field plate structure 503, the third field plate structure 503 and the fourth field plate structure 503 being located in the dielectric layer 80 and the third field plate structure 503 being located between the second gate 302 and the third drain 203, the fourth field plate structure 504 being located between the third gate 303 and the fourth drain 204, and the third field plate structure 503 and the fourth field plate structure 504 being both connected to the source metal electrode 102.

[0055] In an embodiment of the present invention, the lateral dimension of the first cell structure cell1 of the gallium nitride bidirectional switch device is Lpitch=Ld+Lg+2Lgd, where Ld is the lateral dimension of the first drain 201 or the second drain 202, Lg is the lateral dimension of the first gate 301, and Lgd is the lateral dimension between the first gate 301 and the first drain 201 or between the first gate 301 and the second drain 202. The distance between the first drain 201 and the first gate 301 is equal to the distance between the second drain 202 and the first gate 301. As can be seen from the expressions, the lateral dimension (chip area) and specific on-resistance Ron,sp of the first cell structure cell1 of the gallium nitride bidirectional switch device are significantly reduced, so that the lateral dimension (chip area) and specific on-resistance Ron,sp of the fabricated gallium nitride bidirectional switch device are also significantly reduced, thereby reducing chip cost.

[0056] In the embodiment of the present invention, the substrate 111 includes one of a Si substrate, a SiC substrate, an AlN substrate, and an Al2O3 substrate.

[0057] In the embodiment of the present invention, the buffer layer 112 is a GaN layer.

[0058] In the embodiment of the present invention, the barrier layer 113 is one of an AlGaN barrier layer, an AlN barrier layer, and an InAlN barrier layer.

[0059] In an embodiment of the present invention, the first field plate structure 501 and the second field plate structure 502 are connected to the source metal electrode 101 of the first cell structure cell1, and the third field plate structure 503 and the fourth field plate structure 504 are connected to the source metal electrode 102 of the second cell structure cell2. The first field plate structure 501 to the fourth field plate structure 504 are all source field plates, so that the first field plate structure 501 to the fourth field plate structure 504 apply a source voltage to the barrier layer 113.

[0060] In the embodiment of the present invention, the first field plate structure 501 to the fourth field plate structure 504 are arranged in the dielectric layer 80 and connected to the corresponding source metal electrode 101 of the first cell structure cell1 and the source metal electrode 102 of the second cell structure cell2 through the through-hole metal 60.

[0061] In the embodiment of the present invention, Figure 4As shown, the first field plate junction 501 and the second field plate structure 502 in the first cell structure cell1 of the gallium nitride bidirectional switch device are both two-layer field plates. The first field plate 511 in the first field plate structure 501 and the first field plate 521 in the second field plate structure 502 are at the same distance from the barrier layer 113 and at the same distance from the first gate 301. The second field plate 512 in the first field plate structure 501 and the second field plate 522 in the second field plate structure 502 are at the same distance from the barrier layer 11 and at the same distance from the first gate 301. The distance between the first field plate and the barrier layer 113 is smaller than the distance between the second field plate and the barrier layer 113, and the distance between the first field plate and the first gate 301 is smaller than the distance between the second field plate and the first gate 301.

[0062] like Figure 5 As shown, the third field plate structure 503 and the fourth field plate structure 504 in the second cell structure cell2 of the gallium nitride bidirectional switch device are both two-layer field plates, the first field plate 531 in the third field plate structure 503 and the first field plate 541 in the fourth field plate structure 504 are at the same distance from the barrier layer 113, and the distance between the first field plate 531 in the third field plate structure 503 and the second gate 302 is the same as the distance between the first field plate 541 in the fourth field plate structure 504 and the third gate 303. 03 and the second field plate 542 in the fourth field plate structure 504 are at the same distance from the barrier layer 113, and the distance between the second field plate 532 in the third field plate structure 503 and the second gate 302 is the same as the distance between the second field plate 542 in the fourth field plate structure 504 and the third gate 303, wherein the distance between the first field plate and the barrier layer 113 is smaller than the distance between the second field plate and the barrier layer 113, and the distance between the first field plate and the second gate 302 is smaller than the distance between the second field plate and the third gate 303.

[0063] In other embodiments, the distance between the first field plate and the first gate is greater than the distance between the second field plate and the first gate, and the distance between the first field plate and the second gate in the second cellular structure is greater than the distance between the second field plate and the fourth gate.

[0064] In other embodiments, the first to fourth field plate structures in the gallium nitride bidirectional switch device are single-layer field plates, three-layer field plates, or other suitable number of field plate layers.

[0065] In an embodiment of the present invention, the first gate 301 in the first cell structure cell1 further includes a first gate metal electrode 401, which is located on the surface of the first gate 301; the second gate 302 in the second cell structure cell2 further includes a second gate metal electrode 402, which is located on the surface of the second gate 302; the third gate 303 in the second cell structure cell2 further includes a third gate metal electrode 403, which is located on the surface of the third gate 303.

[0066] In the embodiment of the present invention, the first gate 301 to the third gate 303 are formed of a material selected from the group consisting of a PGaN layer, a MIS layer, and a recessed MIS layer.

[0067] In the embodiment of the present invention, Figure 4 As shown, a first drain metal electrode 701 is provided on the surface of the dielectric layer 80 in the first cell structure cell1 and in the area of ​​the orthographic projection of the first drain electrode 201, and a second drain metal electrode 702 is provided in the area of ​​the orthographic projection of the second drain electrode 202. The first metal drain electrode 701 and the second metal drain electrode 702 are connected to the corresponding first drain electrode 201 and the second drain electrode 202 through the through-hole metal 60;

[0068] A third drain metal electrode 703 is provided on the surface of the dielectric layer 80 in the second cell structure cell2 and in the area where the third drain 203 is projected, and a fourth drain metal electrode 704 is provided in the area where the fourth drain 204 is projected. The third metal drain 703 and the fourth metal drain 704 are connected to the corresponding third drain 203 and the fourth drain 204 through a through-hole metal 60.

[0069] In the embodiment of the present invention, the gallium nitride bidirectional switch device includes at least one first cell structure cell1 and at least one second cell structure cell2.

[0070] The second cell structure cell2 and the first cell structure cell1 are arranged in parallel, and the adjacent second cell structure cell2 and the first cell structure cell1 or the second cell structure cell2 and the second cell structure cell2 or the first cell structure cell1 and the first cell structure cell1 share a drain.

[0071] In the embodiment of the present invention, Figure 6-Figure 7As shown, the gallium nitride bidirectional device includes a plurality of first cellular structures cell1 and a plurality of second cellular structures cell2, the first cellular structures cell1 and the second cellular structures cell2 are dispersedly arranged, and the ports on the same side of the first cellular structure cell1 and the second cellular structure cell2 are interconnected, so that the gallium nitride bidirectional device is comb-shaped; as shown Figure 8 As shown, it is a schematic cross-sectional view AA of the interconnection of two adjacent first cell structures cell1 and second cell structures cell2, wherein the second drain in the first cell structure cell1 and the fourth drain in the second cell structure cell2 are the first common drain 205, and the first common drain 205 is connected to the first common drain metal electrode 705 through the through-hole metal 60; Figure 9 As shown, it is a cross-sectional schematic diagram of the interconnection of two adjacent first cell structures cell1, where the second drains in the two adjacent first cell structures cell1 are the second common drain 206, which is connected to the second common drain metal electrode 706 through the through-hole metal 60.

[0072] The source electrode 10 in the second cell structure cell2 serves as the source electrode of the gallium nitride bidirectional device. Since the ports on the same side of the first cell structure cell1 and the second cell structure cell2 are interconnected, the source metal electrode 101 in the first cell structure cell1 region is interconnected with the source electrode 10 in the second cell structure cell2. Therefore, during the application of the prepared gallium nitride bidirectional switch device, the source metal electrode 101 in the first cell structure cell1 region is connected to the source electrode 10 in the second cell structure cell2, that is, connected to the source electrode of the gallium nitride bidirectional device. The source of the device is connected to the ground, providing a reference ground for the first gate 301. The first gate 301 uses the source 10 as a reference electrode, so that the first gate 301 is normally turned on, and the formed gallium nitride bidirectional switch device is normally turned on. This avoids the situation where the gallium nitride bidirectional switch device has no source and the first gate 301 has no reference ground, resulting in the gallium nitride bidirectional switch device being unable to turn on normally, or the first gate 301 can only refer to the voltage of the first drain 201 or the second drain 202. This avoids the need to set a high-voltage isolation drive circuit for the gallium nitride bidirectional switch device, effectively improving the robustness of the bidirectional switch device and facilitating drive control.

[0073] At the same time, the first field plate structure 501 and the second field plate structure 502 of the first cellular structure cell1 are both connected to the source metal electrode 101 of the first cellular structure cell1 region. The first field plate structure 501 and the second field plate structure 502 are source field plate structures, which avoid the increase of the parasitic capacitance Cgd between the gate and the drain of the gallium nitride bidirectional switch device caused by the gate field plate, thereby avoiding the risk of false start-up of the gallium nitride bidirectional switch device and effectively improving the robustness of the bidirectional switch device.

[0074] In the embodiment of the present invention, the gate width Wg of the second cell structure cell2 is equal to the gate width Wg of the first cell structure.

[0075] In other embodiments, the gate width of the second cellular structure is greater than the gate width of the first cellular structure, or the gate width of the second cellular structure is less than the gate width of the first cellular structure.

[0076] In other embodiments, such as Figure 10 As shown, the gallium nitride bidirectional device includes a plurality of first cell structures cell1 and a plurality of second cell structures cell2, the first cell structures cell1 and the second cell structures cell2 are dispersedly arranged, and ports on both sides of the first cell structures cell1 and the second cell structures cell2 are interconnected.

[0077] In other embodiments, such as Figure 11 As shown, the gallium nitride bidirectional device includes a plurality of first cell structures cell1 and one second cell structure cell2, wherein the second cell structure cell2 is located on one side of the gallium nitride bidirectional device, and adjacent first cell structures cell1 and the first cell structure cell1 and the second cell structure cell2 share a drain, the active regions of the first cell structure cell1 and the second cell structure cell2 are connected, and the gate width Wg2 of the second cell structure is smaller than the gate width Wg1 of the first cell structure.

[0078] The second cellular structure and the first cellular structure are arranged in parallel and the active area of ​​the second cellular structure is separated from the active area of ​​the first cellular structure, or the active area of ​​the second cellular structure is separated from the active area of ​​the second cellular structure, or the active area of ​​the first cellular structure is separated from the active area of ​​the first cellular structure.

[0079] In other embodiments, Figure 12As shown, the gallium nitride bidirectional device includes multiple first cellular structures cell1 and one second cellular structure cell2, and one second cellular structure cell2 is located on one side of the gallium nitride bidirectional device, wherein adjacent first cellular structures cell1 share a drain, the active areas of multiple first cellular structures cell1 are separated from the active area of ​​one second cellular structure cell2, the second cellular structure cell2 does not share a drain with the multiple first cellular structures cell1, and the gate width Wg2 of the second cellular structure cell2 is smaller than the gate width Wg1 of the first cellular structure cell1.

[0080] In other embodiments, a distance La between the active area of ​​the second cellular structure cell2 and the active area of ​​the first cellular structure cell1 ranges from 1 um to 10 mm.

[0081] In an embodiment of the present invention, the second cellular structure cell2 and the first cellular structure cell2 are prepared on a unified process platform.

[0082] The present invention further provides a gallium nitride bidirectional switch device, comprising a plurality of the above-mentioned gallium nitride bidirectional switch devices, wherein the plurality of gallium nitride bidirectional switch devices are connected in series or in parallel.

[0083] The present invention also provides a method for preparing the first cell structure of a gallium nitride bidirectional switch device, comprising:

[0084] forming a first drain electrode, a second drain electrode, and a first gate electrode on the surface of the barrier layer, wherein the first drain electrode and the second drain electrode are spaced apart, and the first gate electrode is disposed between the first drain electrode and the second drain electrode;

[0085] A dielectric layer is formed on the surfaces of the first gate, the first drain, and the second drain, and a first field plate structure and a second field plate structure are formed in the dielectric layer, wherein the first field plate structure is located between the first gate and the first drain, and the second field plate structure is located between the first gate and the second drain;

[0086] A source metal electrode is provided on the surface of the dielectric layer, and the source metal electrode is connected to the first field plate structure and the second field plate structure.

[0087] In the embodiment of the present invention, Figure 4As shown, the first field plate structure 501 and the second field plate structure 502 are both two-layer field plates, the first field plate 511 in the first field plate structure 501 and the first field plate 521 in the second field plate structure 502 are at the same distance from the barrier layer 113 and the same distance from the first gate 301, the second field plate 512 in the first field plate structure 501 and the second field plate 522 in the second field plate structure 502 are at the same distance from the barrier layer 113 and the same distance from the first gate 301, wherein the distance between the first field plate and the barrier layer 113 is smaller than the distance between the second field plate and the barrier layer 113, and the distance between the first field plate and the first gate 301 is smaller than the distance between the second field plate and the first gate 301.

[0088] In the embodiment of the present invention, Figure 4 As shown, a first drain metal electrode 701 is provided on the surface of the dielectric layer 80 and in the area where the first drain 202 is projected, and a second drain metal electrode 702 is provided in the area where the second drain 202 is projected. The first metal drain 701 and the second metal drain 702 are connected to the corresponding first drain 201 and the second drain 202 through a through-hole metal 60.

[0089] In an embodiment of the present invention, the source metal electrode 101 , the first drain metal electrode 701 , and the second drain metal electrode 702 in the first cell structure are made of the same metal material and are manufactured simultaneously.

[0090] The embodiment of the present invention also provides a method for preparing a gallium nitride bidirectional device, such as Figure 13 Shown, including:

[0091] Step S10, providing a substrate, wherein the substrate includes a first cellular structure region and a second cellular structure region;

[0092] Step S20, forming a buffer layer on the surface of the substrate, and forming a barrier layer on the surface of the buffer layer;

[0093] Step S30, forming a first drain, a second drain, and a gate on the surface of the barrier layer and in the first cellular structure region, and forming a third drain, a fourth drain, a second gate, a third gate, and a source in the second cellular structure region, wherein the first drain and the second drain are spaced apart, the first gate is disposed between the first drain and the second drain, the source is located between the third drain and the fourth drain, the second gate is located between the third drain and the source, and the third gate is located between the fourth drain and the source;

[0094] Step S40, forming a dielectric layer on the surfaces of the barrier layer, the first gate, the first drain, the second drain, the third drain, the fourth drain, the second gate, the third gate, and the source, and forming a first field plate structure, a second field plate structure, a third field plate structure, and a fourth field plate structure in the dielectric layer, wherein the first field plate structure is located between the first gate and the first drain, the second field plate structure is located between the first gate and the second drain, the third field plate structure is located between the second gate and the third drain, and the fourth field plate structure is located between the second gate and the fourth drain;

[0095] Step S50: forming a source metal electrode on the surface of the dielectric layer and in the first cellular structure region and the second cellular structure region, wherein the source metal electrode in the first cellular structure region is connected to the first field plate structure and the second field plate structure, and the source metal electrode in the second cellular structure region is connected to the third field plate structure and the fourth field plate structure.

[0096] Finally, it should be noted that any modification or equivalent replacement of part or all of the technical features based on the device structure of the present invention and the technical solutions of the embodiments, which does not deviate from the essence of the corresponding technical solutions of the present invention, falls within the patent scope of the device structure of the present invention and the implementation scheme.

Claims

1. A gallium nitride bidirectional switch device, characterized in that: comprising a first cellular structure and a second cellular structure, wherein the second cellular structure and the first cellular structure are arranged in parallel; The first cell structure includes: a substrate, a buffer layer located on the surface of the substrate, and a barrier layer located on the surface of the buffer layer; a first drain and a second drain, the first drain and the second drain being located on the surface of the barrier layer and spaced apart; a first gate, the first gate being located on the surface of the barrier layer and disposed between the first drain and the second drain; a dielectric layer, the dielectric layer being located on the surface of the barrier layer, the first gate, the first drain, and the second drain; a source metal electrode located on the surface of the dielectric layer; a first field plate structure and a second field plate structure, the first field plate structure and the second field plate structure being located in the dielectric layer and the first field plate structure being located between the first gate and the first drain, the second field plate structure being located between the first gate and the second drain, the first field plate structure and the second field plate structure being connected to the source metal electrode, so that the first field plate structure and the second field plate structure apply a source voltage to the barrier layer; The second cellular structure includes: a substrate, a buffer layer located on the surface of the substrate, and a barrier layer located on the surface of the buffer layer; a third drain, a fourth drain, a second gate, a third gate and a source located on the surface of the barrier layer, the source being located between the third drain and the fourth drain, the second gate being located between the third drain and the source, and the third gate being located between the fourth drain and the source; a dielectric layer, the dielectric layer being located on the surfaces of the barrier layer, the third drain, the fourth drain, the second gate, the third gate and the source; and a source metal electrode located on the surface of the dielectric layer, the source metal electrode being connected to the source.

2. The gallium nitride bidirectional switch device according to claim 1, wherein: The second cellular structure also includes: a third field plate structure and a fourth field plate structure located in the dielectric layer, the third field plate structure is located between the second gate and the third drain, the fourth field plate structure is located between the second gate and the fourth drain, and the third field plate structure and the fourth field plate structure are both connected to the source metal electrode.

3. The gallium nitride bidirectional switch device according to claim 2, wherein: The first field plate structure to the fourth field plate structure each include a single-layer field plate or a multi-layer field plate.

4. The gallium nitride bidirectional switch device according to claim 1, wherein: It includes at least one of the first cellular structures and at least one of the second cellular structures.

5. The gallium nitride bidirectional switch device according to claim 1, wherein: The gate width of the second cell structure is equal to the gate width of the first cell structure, or the gate width of the second cell structure is not equal to the gate width of the first cell structure.

6. The gallium nitride bidirectional switch device according to claim 1, characterized in that: The second cellular structure and the first cellular structure are arranged in parallel, and the adjacent second cellular structure and the first cellular structure, or the second cellular structure and the second cellular structure, or the first cellular structure and the first cellular structure share a drain.

7. The gallium nitride bidirectional switch device according to claim 1, characterized in that: The second cellular structure and the first cellular structure are arranged in parallel, and the adjacent active areas of the second cellular structure and the first cellular structure, or the active areas of the second cellular structure and the second cellular structure, or the active areas of the first cellular structure and the first cellular structure are separated.

8. The gallium nitride bidirectional switch device according to claim 1, wherein: The second cellular structure and the first cellular structure are prepared on the same process platform.

9. A method for preparing a gallium nitride bidirectional switch device according to claim 1, characterized in that: include: Providing a substrate, the substrate comprising a first cellular structure region and a second cellular structure region; forming a buffer layer on the surface of the substrate, and forming a barrier layer on the surface of the buffer layer; A first drain, a second drain, and a first gate are formed on the surface of the barrier layer and in the first cellular structure region, and a third drain, a fourth drain, a second gate, a third gate, and a source are formed in the second cellular structure region; the first drain and the second drain are spaced apart, the first gate is disposed between the first drain and the second drain, the source is located between the third drain and the fourth drain, the second gate is located between the third drain and the source, and the third gate is located between the fourth drain and the source; A dielectric layer is formed on the surfaces of the barrier layer, the first gate, the first drain, the second drain, the third drain, the fourth drain, the second gate, the third gate, and the source, and a first field plate structure and a second field plate structure are formed in the dielectric layer, the first field plate structure is located between the first gate and the first drain, and the second field plate structure is located between the first gate and the second drain; A source metal electrode is formed on the surface of the dielectric layer and in the first cellular structure region and the second cellular structure region. The source metal electrode is connected to the source. The source metal electrode in the first cellular structure region is connected to the first field plate structure and the second field plate structure.

10. The method for preparing a gallium nitride bidirectional switch device according to claim 9, wherein: A third field plate structure and a fourth field plate structure are formed in the dielectric layer, the third field plate structure is located between the second gate and the third drain, the fourth field plate structure is located between the second gate and the fourth drain, and the third field plate structure and the fourth field plate structure are both connected to the source metal electrode of the second cellular structure region.

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