Gallium nitride power device and method of manufacturing the same

Abstract

The application provides a gallium nitride power device, including: a substrate; a channel layer on the substrate; a barrier layer on the channel layer; a gate structure; a source ohmic contact metal and a drain ohmic contact metal; the gallium nitride power device further includes: a plurality of second p-type gallium nitride regions arranged at intervals along a first direction, the second p-type gallium nitride regions are formed above the barrier layer, and the second p-type gallium nitride regions are located on a side of the drain ohmic contact metal away from the gate structure; and a plurality of conductive connection structures arranged at intervals along the first direction, the conductive connection structures electrically connect the drain ohmic contact metal and the second p-type gallium nitride regions; wherein the second p-type gallium nitride regions are configured to generate holes near the second p-type gallium nitride regions after a voltage difference between the drain ohmic contact metal and the source ohmic contact metal is greater than a preset threshold value, so that the holes recombine with trap electrons near the drain ohmic contact metal to restore the conductivity of a two-dimensional electron gas channel.

Description

Technical Field

[0001] This application relates to the semiconductor field, and more particularly to a gallium nitride power device and a method for manufacturing the same. Background Technology

[0002] The description in this section provides only background information relevant to the disclosure of this application and does not constitute prior art.

[0003] Gallium nitride high electron mobility transistors (HEMTs) have been widely used in power electronics due to their advantages such as high breakdown voltage, high electron mobility, and low on-resistance. Typical GaN HEMT devices utilize the two-dimensional electron gas (2DEG) formed at the AlGaN / GaN heterojunction interface as the conductive channel.

[0004] For enhancement-mode (normally off) GaN HEMTs, the current mainstream technical solution is to set a p-type gallium nitride layer (p-GaN, p-type doped GaN, such as Mg doped) in the gate region. The p-GaN layer depletes the two-dimensional electron gas below it, thereby achieving the normally off characteristic of the device. Specifically, a typical gallium nitride enhancement-mode device structure includes: a gate, wherein the gate includes a p-type gallium nitride layer, a contact metal layer formed above the p-type gallium nitride layer, and a gate metal (GM) formed above the contact metal layer. The gallium nitride enhancement-mode device structure may also include a first field plate (FP1), a source ohmic contact metal, a drain ohmic metal (OHM), a second field plate (FP2) disposed in the same layer as the source ohmic contact metal and the drain ohmic metal, a third field plate (FP3) disposed in the same layer as the gate metal (GM), and a source-drain metal layer (M1) serving as a fourth field plate. The source ohmic contact metal and the drain ohmic metal (OHM) are electrically connected to the source metal layer and the drain metal layer respectively through contact vias (VIA).

[0005] A patent document CN112331719B published in the Chinese patent database discloses a semiconductor device and a method for manufacturing the semiconductor device. It discloses a structure in which multiple second p-type doped nitride semiconductor bumps are electrically connected to the drain through a drain field plate.

[0006] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0007] Through the inventor's ingenious discovery, hot electrons are generated during hard switching. These hot electrons trap near the drain, forming negatively charged trapped electrons. These negatively charged trapped electrons deplete the two-dimensional electron gas channel, thereby increasing the on-resistance of the device, leading to dynamic resistance degradation and affecting the device's efficiency and reliability.

[0008] Through the inventive discovery of the inventor, CN112331719B in the prior art is connected through a drain field plate. The drain field plate may introduce new electric field peaks, aggravate the hot electron effect, and cause dynamic resistance degradation.

[0009] Based on the aforementioned deficiencies in the prior art, this application provides a gallium nitride power device and its manufacturing method to improve the dynamic resistance characteristics of the device.

[0010] To achieve the above objectives, this application provides the following technical solution: a gallium nitride power device, comprising: Substrate; The trench layer located on the substrate; A barrier layer is located on the channel layer, and a two-dimensional electron gas channel is formed between the channel layer and the barrier layer; A gate structure located on the barrier layer, the gate structure comprising a first p-type gallium nitride region and a gate metal located on the first p-type gallium nitride region; The source ohmic contact metal and the drain ohmic contact metal pass through the barrier layer and contact the channel layer, and the source ohmic contact metal and the drain ohmic contact metal are respectively located on both sides of the gate structure; The drain ohmic contact metal extends along a first direction; The gallium nitride power device also includes: A plurality of second p-type gallium nitride regions are spaced apart along a first direction, the second p-type gallium nitride regions being formed above the barrier layer, and any one of the second p-type gallium nitride regions being located on the side of the drain ohmic contact metal opposite to the gate structure; and Multiple conductive connection structures are spaced apart along a first direction, and any one of the conductive connection structures electrically connects the drain ohmic contact metal to the corresponding second p-type gallium nitride region. In this configuration, any one of the second p-type gallium nitride regions is configured such that, after the voltage difference between the drain ohmic contact metal and the source ohmic contact metal exceeds a preset threshold, the second p-type gallium nitride region is used to generate holes in its vicinity, so that the holes recombine with the trapped electrons near the drain ohmic contact metal to restore the conductivity of the two-dimensional electron gas channel.

[0011] Preferably, the conductive connection structure and the gate metal are formed from the same metal layer and in the same process step.

[0012] Preferably, the second p-type gallium nitride region and the first p-type gallium nitride region are formed in the same process step.

[0013] Preferably, the second p-type gallium nitride region has the same thickness, doped ions, and doped ion concentration as the first p-type gallium nitride region.

[0014] Preferably, the second p-type gallium nitride region is disposed adjacent to the drain ohmic contact metal.

[0015] Preferably, the spacing between the second p-type gallium nitride region and the drain ohmic contact metal is between 0.5 μm and 1 μm.

[0016] Preferably, a first contact metal layer is disposed between the first p-type gallium nitride region and the gate metal, and a second contact metal layer is disposed between the second p-type gallium nitride region and the conductive connection structure. The first contact metal layer and the second contact metal layer are formed from the same metal layer and are formed in the same process step.

[0017] Preferably, it further includes: The first field plate is disposed above the gate metal; The second field plate is formed from the same metal layer as the source ohmic contact metal and is formed in the same process step; The third field plate is formed from the same metal layer as the conductive connection structure and is formed in the same process step.

[0018] Preferably, the second p-type gallium nitride region is configured such that, during the switching process of the power device, the second p-type gallium nitride region is used to generate holes in its vicinity, so that the holes recombine with trapped electrons near the drain ohmic contact metal to restore the conductivity of the two-dimensional electron gas channel.

[0019] This application discloses a method for manufacturing a gallium nitride power device, including the following steps: A channel layer and a barrier layer are sequentially formed on the substrate; A first p-type gallium nitride region and a plurality of second p-type gallium nitride regions are formed on the barrier layer, wherein the plurality of second p-type gallium nitride regions are arranged at intervals; A first dielectric layer is deposited in the first p-type gallium nitride region, the second p-type gallium nitride region, and the barrier layer not covered by the first p-type gallium nitride region and the second p-type gallium nitride region. Then, an ohmic opening is made in the source region and the drain region. The ohmic opening penetrates the first dielectric layer and the barrier layer and ends at the channel layer. After the ohmic opening, source ohmic contact metal and drain ohmic contact metal are formed; After forming the source ohmic contact metal and the drain ohmic contact metal, a second dielectric layer is deposited, and then a contact opening is formed directly above the first p-type gallium nitride region, the second p-type gallium nitride region, and the drain ohmic contact metal. After the contact opening is formed, conductive metal is deposited and patterned to form a gate metal and a plurality of conductive connection structures, wherein any one of the conductive connection structures electrically connects the drain ohmic contact metal to the corresponding second p-type gallium nitride region; wherein any one of the second p-type gallium nitride regions is configured such that when the drain ohmic contact metal is at a high potential, a hole is generated near the second p-type gallium nitride region, and the hole recombines with a trap electron near the drain ohmic contact metal.

[0020] The beneficial effects of this application, achieved through the above technical solution, are as follows: By retaining multiple second p-type gallium nitride regions (PG) near the drain ohmic contact metal (OHM) and electrically connecting the drain ohmic contact metal and the second p-type gallium nitride regions through multiple corresponding conductive connection structures (GM-2), no new electric field spikes are introduced, thus preventing dynamic resistance degradation. When the device operates in hard-switching mode and the drain is at a high potential, holes are generated near the second p-type gallium nitride regions. These holes recombine with negatively charged trapped electrons formed near the drain due to the hot electron trap effect, thereby eliminating the depletion effect of trapped electrons on the two-dimensional electron gas channel, restoring the device's on-resistance, and effectively suppressing the dynamic resistance degradation problem. Therefore, the gallium nitride power device of this invention has better dynamic resistance characteristics and exhibits lower conduction losses and higher reliability in hard-switching applications.

[0021] Specific embodiments of this application are disclosed in detail with reference to the following description and accompanying drawings, illustrating how the principles of this application can be employed. It should be understood that the embodiments of this application are not limited in scope. Within the spirit and scope of the appended claims, the embodiments of this application include many changes, modifications, and equivalents.

[0022] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0023] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0024] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this application in any way. Furthermore, the shapes and scales of the components in the drawings are merely illustrative to aid in understanding this application and do not specifically limit the shapes and scales of the components. Those skilled in the art, guided by the teachings of this application, can select various possible shapes and scales to implement this application according to specific circumstances. In the drawings: Figure 1 A schematic diagram of the structure of a gallium nitride power device in the prior art is shown.

[0025] Figure 2 A top view of the drain layout of the gallium nitride power device in this application is shown.

[0026] Figure 3A It shows Figure 2 Schematic diagram of section A'.

[0027] Figure 3B It shows Figure 2 Schematic diagram of section B' in the middle.

[0028] Figures 4A-4C It shows Figure 2 A schematic diagram of the manufacturing process of a portion of the drain terminal of a gallium nitride power device.

[0029] The reference numerals in the above figures are as follows: 1. Channel layer; 2. Barrier layer; 31. First p-type gallium nitride region; 32. Second p-type gallium nitride region; 41. First contact metal layer; 42. Second contact metal layer; 51. Source ohmic contact metal; 52. Drain ohmic contact metal; 61. Gate metal; 62. Conductive connection structure. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0031] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0034] It should be noted that in the description of this application, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "multiple" means two or more.

[0035] Reference Figure 2 , Figure 3A and Figure 3B As shown in the embodiment of this application, a gallium nitride power device is disclosed, comprising: a substrate; a channel layer 1 located on the substrate; a barrier layer 2 located on the channel layer 1, wherein a two-dimensional electron gas channel is formed between the channel layer 1 and the barrier layer 2; a gate structure located on the barrier layer 2, the gate structure comprising a first p-type gallium nitride region 31 and a gate metal 61 located on the first p-type gallium nitride region 31; a source ohmic contact metal 51 and a drain ohmic contact metal 52 passing through the barrier layer 2 and contacting the channel layer 1, wherein the source ohmic contact metal 51 and the drain ohmic contact metal 52 are respectively located on both sides of the gate structure.

[0036] The plurality of drain ohmic contact metals 52 extend along a first direction. The gallium nitride power device further includes: a plurality of second p-type gallium nitride regions 32 spaced apart along the first direction, the second p-type gallium nitride regions 32 being formed above the barrier layer 2 and located on the side of the drain ohmic contact metals 52 away from the gate structure; and a plurality of conductive connection structures 62 spaced apart along the first direction, the number of the conductive connection structures 62 being the same as the number of the second p-type gallium nitride regions 32, and corresponding one-to-one. Each of the conductive connection structures 62 electrically connects the drain ohmic contact metal 52 and the second p-type gallium nitride region 32 corresponding to the conductive connection structure 62; wherein, any one of the second p-type gallium nitride regions 32 is configured to generate holes in its vicinity after the voltage difference between the drain ohmic contact metal 52 and the source ohmic contact metal 51 exceeds a preset threshold, so that the holes recombine with the trapped electrons near the drain ohmic contact metal 52 to restore the conductivity of the two-dimensional electron gas channel.

[0037] Similar to existing technologies, the substrate can be a silicon (Si) substrate, or a substrate composed of several materials such as silicon on insulator (SOI). The substrate thickness typically ranges from 300µm to 3000µm. When using a Si substrate, its resistivity ranges from 0.001 to 5000 Ω·cm.

[0038] Typically, a buffer layer, a channel layer 1, and a barrier layer 2 are sequentially formed on top of the substrate using an MOVCD.

[0039] The buffer layer can be made of different materials depending on the substrate and specific requirements. For example, when using a silicon substrate, it can consist of an AlN nucleation layer, one or more AlGaN transition layers, a superlattice buffer layer formed by alternating AlN and AlGaN layers, and a high-carbon layer (carbon concentration greater than 10). 18 cm -3 It can be composed of GaN layers, or sequentially of AlN nucleation layers, one or more AlGaN layers, and high carbon (carbon concentration greater than 10). 18 cm -3 It consists of GaN layers.

[0040] Channel layer 1 can be formed of a semiconductor material, for example, low-carbon (carbon concentration less than 10). 18 cm -3 The barrier layer 2 can be formed of a semiconductor material, such as a ternary or quaternary alloy compound based on gallium nitride, or Al. x Ga 1x N, AlInGaN, In x Ga1x N, Al x In 1x Al, AlScN.

[0041] Similar to existing technologies, in this embodiment, the gate structure includes a first p-type gallium nitride region 31 (p-GaN), a first contact metal layer 41 formed above the first p-type gallium nitride region 31, and a gate metal 61 formed above the first contact metal layer 41. The first p-type gallium nitride region 31 is typically doped with magnesium, etc. The first contact metal layer 41 can be a combination of TiN, Ti-related materials, or a combination of Ni / Au, or other similar metal combinations, etc. Source ohmic contact metal 51 and drain ohmic contact metal 52 are used to form the source region and drain region, respectively, which are located on opposite sides of the gate structure. The source ohmic contact metal 51 and drain ohmic contact metal 52 pass through the barrier layer 2 through ohmic openings and contact the channel layer 1.

[0042] Reference Figure 3A As shown, it can be understood that the cross section AA' of the gallium nitride power device in the embodiments of this application is consistent with that of the conventional gallium nitride enhancement-mode device.

[0043] Reference Figure 3B As shown, unlike existing technologies, the gallium nitride power device further includes a second p-type gallium nitride region 32 and a conductive connection structure 62. The second p-type gallium nitride region 32 is formed above the barrier layer 2 and is located on the side of the drain ohmic contact metal 52 facing away from the gate structure. Preferably, the second p-type gallium nitride region 32 is disposed adjacent to the drain ohmic contact metal 52. Preferably, the spacing between the second p-type gallium nitride region 32 and the drain ohmic contact metal 52 is between 0.5 μm and 1 μm. Unlike existing technologies, the side of the second p-type gallium nitride region 32 cannot be in close contact with the side of the drain ohmic contact metal 52. This is because, in low-temperature ohmic processes, the drain ohmic contact metal 52 needs to penetrate the barrier layer 2. In other words, the ohmic opening at the drain region must penetrate the barrier layer 2. If the distance between the second p-type gallium nitride region 32 and the ohmic opening is too small, the second p-type gallium nitride region 32 may be damaged during the ohmic opening process. Furthermore, hot electrons typically accumulate at the drain corner, and the function of the second p-type gallium nitride region 32 is to generate holes to neutralize hot electrons. If the second p-type gallium nitride region 32 is too far from the drain corner, the improvement in dynamic resistance will be insignificant.

[0044] Any of the conductive connection structures 62 electrically connects the drain ohmic contact metal 52 to the second p-type gallium nitride region 32. The second p-type gallium nitride region 32 is configured to generate holes in its vicinity after the voltage difference between the drain ohmic contact metal 52 and the source ohmic contact metal 51 exceeds a preset threshold, so that the holes recombine with trapped electrons near the drain ohmic contact metal 52 to restore the conductivity of the two-dimensional electron gas channel.

[0045] Each of the conductive connection structures 62 includes a first vertical connection portion located directly above the second p-type gallium nitride region 32 corresponding to the conductive connection structure 62 and extending along the thickness direction of the gallium nitride power device; a second vertical connection portion located directly above the drain ohmic contact metal 52 and extending along the thickness direction of the gallium nitride power device; and a horizontal portion connecting the first and second vertical connection portions. Generally, the first vertical connection portion, the second vertical connection portion, and the horizontal portion have the same length along the first direction. The horizontal portion extends along the second direction. The first direction, the second direction, and the thickness direction of the gallium nitride power device are all perpendicular to each other.

[0046] In this embodiment, the second p-type gallium nitride region 32 is formed in the same process step as the first p-type gallium nitride region 31. The second p-type gallium nitride region 32 has the same thickness, dopant ions, and dopant ion concentration as the first p-type gallium nitride region 31. In this embodiment, the first p-type gallium nitride region 31 and the second p-type gallium nitride region 32 are typically doped with magnesium, etc. Of course, in other optional embodiments, the dopant ions of the first p-type gallium nitride region 31 and the second p-type gallium nitride region 32 can also be Zn, Be, etc.

[0047] The conductive connection structure 62 and the gate metal 61 are formed from the same metal layer and in the same process step. The materials of the conductive connection structure 62 and the gate metal 61 can be TiN, Ti-related combinations, Ni / Au combinations, or other similar metal combinations.

[0048] A first contact metal layer 41 is disposed between the first p-type gallium nitride region 31 and the gate metal 61, and a second contact metal layer 42 is disposed between the second p-type gallium nitride region 32 and the conductive connection structure 62. The first contact metal layer 41 and the second contact metal layer 42 are formed from the same metal layer and in the same process step. The materials of the first contact metal layer 41 and the second contact metal layer 42 are selected from at least one of the following: TiN, TaN, ZrN, Ni / Au, Ni / Ti / Au, Pd / Au, Ti / TiN / Cu, Ti / Al / TiN.

[0049] Combination Figure 3A and Figure 3B As shown, the second p-type gallium nitride region 32 (and the second contact metal layer 42) extends along the length direction (first direction) of the drain fingers, gate fingers, and source fingers. However, it is clear that the second p-type gallium nitride region 32 (and the second contact metal layer 42) and the conductive connection structure 62 only extend a predetermined value along the first direction, and do not have the length of these fingers. Generally, the length of one second p-type gallium nitride region 32 along the drain finger extension direction is 1-2 μm, and the spacing formed between multiple second p-type gallium nitride regions 32 and multiple conductive connection structures 32 can be set as needed. If the length of the second p-type gallium nitride region 32 is too large, due to its proximity effect, the conduction state will hinder the electron velocity, and the device resistance will increase; if the length of the second p-type gallium nitride region 32 is too small, the hole injection effect is weakened, and the improvement in dynamic resistance is not significant. The core function of the second p-type gallium nitride region 32 is to generate holes during hard switching, which recombine with trapped electrons near the drain, restoring the conductivity of the two-dimensional electron gas channel 4. The specific working mechanism is as follows: When the device performs a hard switch operation and is in the off state, the potential of the drain ohmic contact metal 52 rises to a high voltage (e.g., 200-600V), while the potential of the source ohmic contact metal 51 is close to zero. Since the second p-type gallium nitride region 32 is electrically connected to the drain ohmic contact metal 52 through the conductive connection structure 62, the potential of the second p-type gallium nitride region 32 is pulled up to near the drain potential. At this time, the second p-type gallium nitride region 32 and the underlying barrier layer 2 (AlGaN layer) form a forward-biased pn junction.

[0050] Under the influence of a strong electric field, the pn junction undergoes collisional ionization, generating a large number of electron-hole pairs. Newly generated holes accumulate near the second p-type gallium nitride region 32 under the influence of the electric field. Simultaneously, high-energy hot electrons generated during the hard-switching process are captured by semiconductor defects or interface states near the drain, forming negatively charged trapped electrons. These trapped electrons deplete the underlying two-dimensional electron gas channel, leading to a decrease in the two-dimensional electron gas concentration and a significant increase in the device's on-resistance.

[0051] Because the second p-type gallium nitride region 32 is adjacent to the drain ohmic contact metal 52, the holes accumulated nearby are spatially very close to the trapped electrons near the drain, and the positive and negative charges attract each other and recombine. After the trapped electrons are neutralized by the holes, their depletion effect on the two-dimensional electron gas channel disappears, the concentration of the two-dimensional electron gas returns to normal, and the on-resistance of the device decreases back to normal, thereby effectively suppressing the dynamic resistance degradation problem and ensuring the efficient operation of the device in high-frequency hard-switching scenarios.

[0052] In addition, the gallium nitride power device also includes a first field plate disposed above the gate metal 61; a second field plate formed from the same metal layer as the source ohmic contact metal 51 and formed in the same process step; and a third field plate formed from the same metal layer as the conductive connection structure 62 and formed in the same process step. The source-drain metal layer (M1) serves as the fourth field plate, and the source ohmic contact metal 51 and the drain ohmic metal (OHM) are electrically connected to the source metal layer and the drain metal layer respectively through contact vias (VIA).

[0053] The manufacturing method of the gallium nitride power device in this embodiment is roughly as follows: A buffer layer, a channel layer 1, and a barrier layer 2 are sequentially formed on the substrate.

[0054] Reference Figure 4A As shown, a first p-type gallium nitride region 31, a first contact metal layer 41, a plurality of second p-type gallium nitride regions 32, and a second contact metal layer 42 are formed on the barrier layer 2. The plurality of second p-type gallium nitride regions 32 are arranged at intervals.

[0055] A first dielectric layer is deposited in the first contact metal layer 41, the second contact metal layer 42, the first p-type gallium nitride region 31, the second p-type gallium nitride region 32, and the barrier layer 2 not covered by the first p-type gallium nitride region 31 and the second p-type gallium nitride region. Then, ohmic openings are made in the source region and the drain region. The ohmic opening in the drain region is adjacent to the second p-type gallium nitride region 32. Generally, the ohmic opening passes through the first dielectric layer and the barrier layer 2 and terminates at the upper interface of the channel layer 1.

[0056] Reference Figure 4B As shown, after the ohmic opening, the ohmic contact metal OHM is deposited and patterned to form the source ohmic contact metal 51 and the drain ohmic contact metal 52.

[0057] After forming the source ohmic contact metal 51 and the drain ohmic contact metal 52, a second dielectric layer is deposited, and then a contact opening is formed directly above the first p-type gallium nitride region 31, the second p-type gallium nitride region 32, and the drain ohmic contact metal 52. Reference Figure 4CAs shown, after the contact opening is formed, conductive metal is deposited and patterned to form gate metal 61 and a plurality of conductive connection structures 62. Each of the conductive connection structures 62 electrically connects the drain ohmic contact metal 52 to the corresponding second p-type gallium nitride region 32. Each of the second p-type gallium nitride regions 32 is configured such that when the drain ohmic contact metal 52 is at a high potential, a hole is generated near the second p-type gallium nitride region 32, and the hole recombines with the trap electrons near the drain ohmic contact metal 52.

[0058] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed application subject matter.

Claims

1. A gallium nitride power device, comprising: Substrate; The trench layer located on the substrate; A barrier layer is located on the channel layer, and a two-dimensional electron gas channel is formed between the channel layer and the barrier layer; A gate structure located on the barrier layer, the gate structure comprising a first p-type gallium nitride region and a gate metal located on the first p-type gallium nitride region; The source ohmic contact metal and the drain ohmic contact metal pass through the barrier layer and contact the channel layer, and the source ohmic contact metal and the drain ohmic contact metal are respectively located on both sides of the gate structure; The characteristic feature is that the drain ohmic contact metal extends along a first direction; The gallium nitride power device also includes: A plurality of second p-type gallium nitride regions are spaced apart along a first direction, the second p-type gallium nitride regions being formed above the barrier layer, and any one of the second p-type gallium nitride regions being located on the side of the drain ohmic contact metal opposite to the gate structure; and Multiple conductive connection structures are spaced apart along a first direction, and any one of the conductive connection structures electrically connects the drain ohmic contact metal to the corresponding second p-type gallium nitride region. In this configuration, any one of the second p-type gallium nitride regions is configured such that, after the voltage difference between the drain ohmic contact metal and the source ohmic contact metal exceeds a preset threshold, the second p-type gallium nitride region is used to generate holes in its vicinity, so that the holes recombine with the trapped electrons near the drain ohmic contact metal to restore the conductivity of the two-dimensional electron gas channel.

2. The gallium nitride power device according to claim 1, characterized in that, The conductive connection structure and the gate metal are formed from the same metal layer and in the same process step.

3. The gallium nitride power device according to claim 1, characterized in that, The second p-type gallium nitride region is formed in the same process step as the first p-type gallium nitride region.

4. The gallium nitride power device according to claim 1, characterized in that, The second p-type gallium nitride region has the same thickness, doped ions, and doped ion concentration as the first p-type gallium nitride region.

5. The gallium nitride power device according to claim 1, characterized in that, The second p-type gallium nitride region is located adjacent to the drain ohmic contact metal.

6. The gallium nitride power device according to claim 1, characterized in that, The spacing between the second p-type gallium nitride region and the drain ohmic contact metal is between 0.5 μm and 1 μm.

7. The gallium nitride power device according to claim 1, characterized in that, A first contact metal layer is disposed between the first p-type gallium nitride region and the gate metal, and a second contact metal layer is disposed between the second p-type gallium nitride region and the conductive connection structure. The first contact metal layer and the second contact metal layer are formed from the same metal layer and are formed in the same process step.

8. The gallium nitride power device according to claim 1, characterized in that, Also includes: The first field plate is disposed above the gate metal; The second field plate is formed from the same metal layer as the source ohmic contact metal and is formed in the same process step; The third field plate is formed from the same metal layer as the conductive connection structure and is formed in the same process step.

9. The gallium nitride power device according to claim 1, characterized in that, The second p-type gallium nitride region is configured such that, during the switching process of the power device, the second p-type gallium nitride region is used to generate holes in its vicinity, so that the holes recombine with trapped electrons near the drain ohmic contact metal to restore the conductivity of the two-dimensional electron gas channel.

10. A method for manufacturing a gallium nitride power device, characterized in that, Includes the following steps: A channel layer and a barrier layer are sequentially formed on the substrate; A first p-type gallium nitride region and a plurality of second p-type gallium nitride regions are formed on the barrier layer, wherein the plurality of second p-type gallium nitride regions are arranged at intervals; A first dielectric layer is deposited in the first p-type gallium nitride region, the second p-type gallium nitride region, and the barrier layer not covered by the first p-type gallium nitride region and the second p-type gallium nitride region. Then, an ohmic opening is made in the source region and the drain region, wherein the ohmic opening penetrates the first dielectric layer and the barrier layer and ends at the channel layer. After the ohmic opening, source ohmic contact metal and drain ohmic contact metal are formed; After forming the source ohmic contact metal and the drain ohmic contact metal, a second dielectric layer is deposited, and then a contact opening is formed directly above the first p-type gallium nitride region, the second p-type gallium nitride region, and the drain ohmic contact metal. After the contact opening is formed, conductive metal is deposited and patterned to form gate metal and multiple conductive connection structures, wherein any one of the conductive connection structures electrically connects the drain ohmic contact metal to the corresponding second p-type gallium nitride region. In this configuration, any one of the second p-type gallium nitride regions is configured such that when the drain ohmic contact metal is at a high potential, a hole is generated near the second p-type gallium nitride region, and the hole recombines with a trap electron near the drain ohmic contact metal.

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