A gallium nitride semiconductor device and chip

Abstract

The application discloses a gallium nitride semiconductor device and a chip, wherein the gallium nitride semiconductor device comprises a semiconductor base material, a multilayer semiconductor layer, a source electrode, a gate structure, a drain electrode and a metal anode; the multilayer semiconductor layer is arranged on the semiconductor base material, and at least one groove structure is arranged on the surface of the semiconductor layer away from the semiconductor base material; the source electrode, the gate structure and the drain electrode are arranged on the surface of the semiconductor layer and are spaced from each other, the gate structure is arranged between the source electrode and the drain electrode; the metal anode is arranged between the gate structure and the drain electrode; the groove structure is arranged between the gate structure and the drain electrode, and the metal anode is arranged on one side of the at least one groove structure close to the gate structure; the metal anode is in contact with the source electrode and the drain electrode through the semiconductor layer to form a reverse freewheeling diode; the reverse freewheeling diode is formed on the gallium nitride semiconductor device, the withstand voltage of the device can be effectively improved, the leakage current of the device is reduced, and the performance of the gallium nitride semiconductor device is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a gallium nitride semiconductor device and chip. Background Technology

[0002] In the application of integrated circuits, the transistors in gallium nitride semiconductor devices generally cannot conduct in reverse. Instead, a diode is usually connected in parallel with the outside to enable the transistor to conduct in reverse.

[0003] In practice, the inventors of this application have found that, in order to avoid the parasitic inductance and capacitance caused by external parallel diodes, the current technical solution is to integrate planar Schottky diodes on transistors; however, planar Schottky diodes have disadvantages such as large reverse leakage current and poor voltage withstand capability, which affect the performance of gallium nitride semiconductor devices. Summary of the Invention

[0004] The main technical problem solved by this invention is to provide a gallium nitride semiconductor device and chip that can effectively improve the device's withstand voltage, reduce the device's leakage current, and improve the capabilities of the gallium nitride semiconductor device.

[0005] To solve the above-mentioned technical problems, this application adopts the following technical solution: A gallium nitride semiconductor device is provided, comprising: a semiconductor substrate, a multilayer semiconductor layer, a source, a gate structure, a drain, and a metal anode. The semiconductor substrate has a first surface; the multilayer semiconductor layer is disposed on the first surface of the semiconductor substrate, and at least one trench structure is formed on the surface of the semiconductor layer away from the semiconductor substrate. The source, gate structure, and drain are disposed at intervals on the surface of the semiconductor layer away from the semiconductor substrate, and the gate structure is disposed between the source and drain; the metal anode is disposed on the surface of the semiconductor layer away from the semiconductor substrate, parallel to a first direction of the source and spaced between the gate structure and the drain, and the metal anode forms a Schottky contact with the semiconductor layer. At least one trench structure is disposed between the gate structure and the drain, and the metal anode is disposed on the side of the at least one trench structure closer to the gate structure, and the other side of the at least one trench structure extends along a second direction from the source to the drain; the metal anode contacts the source and the drain respectively through the semiconductor layer to form a reverse freewheeling diode.

[0006] To solve the above-mentioned technical problems, another technical solution adopted in this application is to provide a chip including the above-mentioned gallium nitride semiconductor device.

[0007] Unlike current technologies, the gallium nitride semiconductor device provided in this application integrates a reverse freewheeling diode by placing a metal anode between the gate and drain of the gallium nitride semiconductor device. A trench structure is formed on the surface of the semiconductor layer between the gate and drain to reduce the concentration of two-dimensional electron gas below the trench structure, modulate the electric field distribution of the channel, improve the breakdown voltage of the gallium nitride semiconductor device, improve the electric field concentration effect near the freewheeling diode, weaken the Schottky barrier reduction effect, reduce the leakage current of the device, and thus improve the performance of the gallium nitride semiconductor device. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0009] Figure 1 This is a schematic diagram of the structure of the first embodiment of the gallium nitride semiconductor device in this application;

[0010] Figure 2 This is a schematic diagram of the structure of the second embodiment of the gallium nitride semiconductor device in this application;

[0011] Figure 3 yes Figure 2 A front view of the second-direction section;

[0012] Figure 4 yes Figure 2 Rear view of the second-direction section;

[0013] Figure 5 This is a schematic diagram of the structure of the third embodiment of the gallium nitride semiconductor device in this application;

[0014] Figure 6 This is a schematic diagram of the structure of the fourth embodiment of the gallium nitride semiconductor device in this application;

[0015] Figure 7 This is a schematic diagram of the structure of the fifth embodiment of the gallium nitride semiconductor device in this application;

[0016] Figure 8 yes Figure 7 A front view of the second-direction section;

[0017] Figure 9 yes Figure 7 Rear view of the second-direction section;

[0018] Figure 10This is a schematic diagram of the structure of the sixth embodiment of the gallium nitride semiconductor device in this application;

[0019] Figure 11 This is a schematic diagram of the structure of the seventh embodiment of the gallium nitride semiconductor device in this application.

[0020] Explanation of reference numerals in the attached figures:

[0021] Semiconductor substrate 100, multilayer semiconductor layer 200, buffer layer 210, channel layer 220, barrier layer 230, source 300, gate structure 400, P-type gallium nitride (P-GaN) structure 410, gate 420, drain 500, metal anode 600, trench structure 700, first trench structure 710, second trench structure 720, third trench structure 730, and fourth trench structure 740. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0024] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0025] The present application will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] Current gallium nitride semiconductor devices, such as HEMTs (High Electron Mobility Transistors), lack direct reverse conduction functionality. This is especially true in many power switching circuits, such as inverters and DC-DC converters, where the power transistor needs to be connected in anti-parallel with a freewheeling diode to achieve reverse conduction. However, because P-GaN gate power HEMTs lack a body diode, the reverse conduction voltage is coupled to the device threshold voltage, resulting in a high reverse conduction voltage, leading to higher energy loss and lower efficiency. External parallel diodes not only increase cost but also introduce additional parasitic inductance and capacitance. Current technology integrates planar Schottky diodes on the HEMT to achieve reverse conduction, but planar Schottky diodes suffer from high reverse leakage current and poor voltage withstand capability.

[0027] Therefore, this application provides a gallium nitride semiconductor device that can effectively improve the device's withstand voltage and reduce the device's leakage current, thereby improving the capabilities of the gallium nitride semiconductor device.

[0028] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of the first embodiment of the gallium nitride semiconductor device in this application.

[0029] like Figure 1As shown, the gallium nitride semiconductor device of this embodiment includes: a semiconductor substrate 100, a multilayer semiconductor layer 200, and a source 300, a gate structure 400, and a drain 500 disposed on the surface of the semiconductor layer 200, and a metal anode 600 disposed on the surface of the semiconductor layer 200; the semiconductor substrate 100 has a first surface, the multilayer semiconductor layer 200 is disposed on the first surface of the semiconductor substrate 100, and at least one trench structure 700 is formed on the surface of the semiconductor layer 200 away from the semiconductor substrate 100; the source 300, the gate structure 400, and the drain 500 are disposed at intervals on the surface of the semiconductor layer 200 away from the semiconductor substrate 100, and the gate structure 400 is disposed between the source 300 and the drain 500; the metal anode 600 is disposed on the surface of the semiconductor layer 200 away from the semiconductor substrate 100, and is parallel to the first direction of the source 300 and disposed at intervals between the gate structure 400 and the drain 500, and the metal anode 600 forms a Schottky contact with the semiconductor layer 200.

[0030] In this embodiment, at least one trench structure 700 is disposed between the gate structure 400 and the drain 500, and a metal anode 600 is disposed on the side of the at least one trench structure 700 close to the gate structure 400. The other side of the at least one trench structure 700 extends along the source 300 to the drain 500 in a second direction. The metal anode 600 contacts the source 300 and the drain 500 respectively through the semiconductor layer 200 to form a reverse freewheeling diode.

[0031] In some embodiments, the width of the trench structure 700 in the second direction can be between 100nm and 5um, such as 500nm, 1um, 2um, etc.

[0032] The first direction is parallel to the source 300, the gate structure 400, and the drain 500, and the second direction is perpendicular to the source 300, the gate structure 400, and the drain 500. The first direction and the second direction are perpendicular to each other on the same horizontal plane. That is, on the same horizontal plane, the direction parallel to the gate structure is set as the first direction, the direction perpendicular to the gate structure is set as the second direction, and the direction perpendicular to the horizontal plane is set as the third direction.

[0033] The semiconductor substrate 100 serves as the substrate for a gallium nitride semiconductor device and can be made of any semiconductor material suitable for semiconductor devices, such as Si, and / or silicon carbide (SiC), and / or SiGe, and / or gallium nitride (GaN), and / or aluminum nitride (AlN), oxide semiconductors (such as zinc oxide (ZnO), gallium oxide (Ga2O3), perovskite (CaTiO3), etc.), and wide-bandgap semiconductor materials such as diamond. In other embodiments, the substrate can also be various composite substrates such as silicon-on-insulator (SOI) and germanium-silicon-on-insulator. Those skilled in the art will understand that the substrate is not limited in any way, but can be selected according to the actual application.

[0034] In some embodiments, the first spacing between the source 300 and the gate structure 400 is not greater than the second spacing between the trench structure 700 and the gate structure 400.

[0035] Specifically, if there is a minimum spacing between the source 300 and the gate structure 400, then the spacing between the trench structure 700 and the gate structure 400 is not less than this minimum spacing, such as the first spacing being equal to the second spacing. It is understood that the minimum spacing between the source 300 and the gate structure 400 is formed due to process limitations; therefore, the first spacing can be equal to the second spacing.

[0036] In some embodiments, the first spacing between the source 300 and the gate structure 400 is not greater than the third spacing between the metal anode 600 and the gate structure 400.

[0037] Specifically, if there is a minimum spacing between the source 300 and the gate structure 400, then the spacing between the trench structure 700 and the gate structure 400 is not less than this minimum spacing, such as the first spacing being equal to the third spacing.

[0038] In some embodiments, the gate structure 400 includes a P-type gallium nitride (P-GaN) structure 410 and a gate 420 stacked sequentially; the P-type gallium nitride (P-GaN) structure 410 is disposed on the surface of the semiconductor layer 200 away from the semiconductor substrate 100, and the gate 420 is disposed on the surface of the P-type gallium nitride (P-GaN) structure 410 away from the semiconductor layer 200; the gate 420 and the P-type gallium nitride (P-GaN) structure 410 form an ohmic contact or a Schottky contact.

[0039] The metal anode 600 is continuous in the direction parallel to the gate structure 400 and is guaranteed to be on a straight line. At this time, the semiconductor layer below the metal anode 600 is equipotential, so that the P-type gallium nitride (P-GaN) structure 410 and the trench structure 700 can effectively adjust the electric field on the side of the equipotential line near the drain 500.

[0040] In this embodiment, a metal anode is provided between the gate and drain of the gallium nitride semiconductor device to form a reverse freewheeling diode on the gallium nitride semiconductor device in an integrated manner. A trench structure is formed on the surface of the semiconductor layer between the gate and drain to reduce the concentration of two-dimensional electron gas under the trench structure, modulate the electric field distribution of the channel, improve the breakdown voltage of the gallium nitride semiconductor device, improve the electric field concentration effect near the freewheeling diode, weaken the Schottky barrier reduction effect, reduce the leakage current of the device, and thus improve the performance of the gallium nitride semiconductor device.

[0041] Please see Figure 2 , Figure 2 This is a schematic diagram of the structure of the second embodiment of the gallium nitride semiconductor device in this application.

[0042] like Figure 2 As shown, the multilayer semiconductor layer 200 includes a buffer layer 210, a channel layer 220, and a barrier layer 230 stacked sequentially along a third direction.

[0043] The third direction is perpendicular to the first and second directions, and the third direction points upwards. At least one trench structure is formed on the surface of the barrier layer 230 away from the channel layer 220. The width of the trench structure 700 in the first direction is not greater than the width of the metal anode 600 in the first direction, and the depth of the trench structure 700 is not greater than the thickness of the barrier layer 230.

[0044] The buffer layer 210 is a semiconductor layer deposited between two layers with a large difference in thermal expansion coefficients to buffer the stress caused by direct contact between the two layers; the channel layer 220 is a conductive layer along the length direction in a semiconductor device caused by an applied electric field, in which the current flow is controlled by the gate potential; the barrier layer 230 is a blocking layer formed by the diffusion of electrons and holes in a PN junction, and the potential energy difference on both sides is called the barrier.

[0045] The buffer layer 210 can be made of semi-insulating, high-resistivity, high-quality gallium nitride (GaN), forming a gallium nitride (GaN) buffer layer with a thickness of 3-4 μm; the channel layer 220 can be made of gallium nitride (GaN), forming a gallium nitride (GaN) channel layer with a thickness of 150-250 nm, such as 200 nm; the barrier layer 230 can be made of aluminum gallium nitride (AlGaN), forming an aluminum gallium nitride (AlGaN) barrier layer with a thickness of 15-30 nm.

[0046] Specifically, such as Figure 2As shown, in this embodiment, silicon carbide (SiC) is used as the semiconductor substrate 100, and gallium nitride (GaN) layer is used as the buffer layer 210, gallium nitride (GaN) layer as the channel layer 220, and aluminum gallium nitride (AlGaN) layer as the barrier layer 230. The following description illustrates the application: A gallium nitride (GaN) layer is disposed on the first surface of the silicon carbide (SiC) substrate as the buffer layer 210. A gallium nitride (GaN) layer is disposed on the buffer layer 210 as the channel layer 220. An aluminum gallium nitride (AlGaN) layer is disposed on the channel layer 220 as the barrier layer 230. Source electrodes 300 are disposed at intervals on the barrier layer 230. A gate structure 400 and a drain 500 are provided, with the gate structure 400 disposed between the source 300 and the drain 500. A metal anode 600 is disposed between the gate structure 400 and the drain 500 in a first direction parallel to the source 300 and spaced apart. A trench structure 700 is disposed between the gate structure 400 and the drain 500, with the metal anode 600 disposed on the side of the trench structure 700 close to the gate structure 400. The other side of the trench structure 700 extends along the source 300 to the drain 500 in a second direction. The metal anode 600 contacts the source 300 and the drain 500 respectively through the semiconductor layer 200 to form a reverse freewheeling diode.

[0047] See Figure 3 and Figure 4 , Figure 3 yes Figure 2 Front view of the second-direction section. Figure 4 yes Figure 2 Rear view of the second-direction section.

[0048] The working principle of the gallium nitride semiconductor device in this application is as follows: The metal anode 600 serves as the anode of the reverse freewheeling diode, and the drain 500 serves as the cathode of the reverse freewheeling diode. When the gallium nitride semiconductor device is forward-biased, current flows from the drain 500 to the source 300. At this time, a positive voltage needs to be applied to the gate structure 400 to open the channel. The 2DEG (Two-Dimensional Electron Gas) in the trench structure 700 region will be depleted or partially depleted, so the current mainly flows through the non-trench structure region. Furthermore, the metal anode 600 and the barrier layer 230 are in Schottky contact, so the reverse freewheeling diode is cut off during forward conduction. When the gallium nitride semiconductor device is reverse-biased, no voltage is applied to the gate structure 400, causing the channel to turn off. At this time, a positive voltage is applied to the source 300, and the current cannot pass through the gate structure 400. Therefore, the current flows from the metal anode 600 to the drain 500. During breakdown voltage testing, the gate structure 400 is turned off, and a high voltage is applied to the drain 500. Both the HEMT (High Electron Mobility Transistor) and the reverse freewheeling diode are turned off simultaneously and both withstand the breakdown voltage. The HEMT and the reverse freewheeling diode share a drift region, but the metal anode 600 of the reverse freewheeling diode is closer to the drain 500. Therefore, the breakdown voltage is actually borne by the section from the metal anode 600 of the reverse freewheeling diode to the drain 500 of the gallium nitride semiconductor device. The reverse freewheeling diode always breaks down before the HEMT. The AlGaN layer, as the trench structure 700 in the barrier layer, reduces or even depletes the two-dimensional electron gas (2DEG) below it, modulates the electric field distribution of the channel, improves the device breakdown voltage, and at the same time improves the electric field concentration effect near the reverse freewheeling diode, weakens the Schottky barrier reduction effect, and reduces the leakage current of the device.

[0049] Please see Figure 5 , Figure 5 This is a schematic diagram of the structure of the third embodiment of the gallium nitride semiconductor device in this application.

[0050] like Figure 5 As shown, the gallium nitride semiconductor device includes a semiconductor substrate 100, a buffer layer 210, a channel layer 220, a barrier layer 230, a source 300, a gate structure 400 and a drain 500 disposed on the barrier layer 230, and a metal anode 600 and a trench structure 700 disposed between the gate structure 400 and the drain 500.

[0051] Specifically, when a portion of the metal anode 600 is located within the trench structure 700, and the depth of the trench structure 700 is less than the thickness of the barrier layer 230, the sidewall of the metal anode 600 near the gate structure 400 contacts the sidewall of the trench structure 700 near the gate structure 400. A portion of the metal anode 600 in the first direction covers a portion of the trench structure 700, and another portion of the metal anode 600 covers a portion of the barrier layer. That is, a portion of the metal anode 600 is within the trench structure 700, and a portion of the metal anode 600 is outside the trench structure 700. The surface of the metal anode 600 outside the trench structure 700 that contacts the barrier layer 230 forms a Schottky contact with the barrier layer. The surface of the metal anode 600 within the trench structure 700 that contacts the barrier layer 230 is on the same horizontal plane as the bottom surface of the trench structure 700, and the sidewall of the metal anode 600 near the gate structure 400 contacts the sidewall of the trench structure 700 near the gate structure 400.

[0052] Please see Figure 6 , Figure 6 This is a schematic diagram of the structure of the fourth embodiment of the gallium nitride semiconductor device in this application.

[0053] like Figure 6 As shown, the gallium nitride semiconductor device includes a semiconductor substrate 100, a buffer layer 210, a channel layer 220, a barrier layer 230, a source 300, a gate structure 400 and a drain 500 disposed on the barrier layer 230, and a metal anode 600 and a trench structure 700 disposed between the gate structure 400 and the drain 500.

[0054] Specifically, when a portion of the metal anode 600 is located within the trench structure 700, and the depth of the trench structure 700 is equal to the thickness of the barrier layer 230, the sidewall of the metal anode 600 near the gate structure 400 contacts the sidewall of the trench structure 700 near the gate structure 400. A portion of the metal anode 600 in the first direction covers a portion of the trench structure 700, and another portion of the metal anode 600 covers a portion of the barrier layer. That is, a portion of the metal anode 600 is within the trench structure 700, and a portion is outside the trench structure 700. The surface of the metal anode 600 outside the trench structure 700 that contacts the barrier layer 230 forms a Schottky contact with the barrier layer. The surface of the metal anode 600 within the trench structure 700 that contacts the channel layer 220 is on the same horizontal plane as the bottom surface of the trench structure 700, and the sidewall of the metal anode 600 near the gate structure 400 contacts the sidewall of the trench structure 700 near the gate structure 400.

[0055] Please see Figure 7 , Figure 7 This is a schematic diagram of the fifth embodiment of the gallium nitride semiconductor device in this application.

[0056] like Figure 7 As shown, the gallium nitride semiconductor device includes a semiconductor substrate 100, a buffer layer 210, a channel layer 220, a barrier layer 230, a source 300, a gate structure 400 and a drain 500 disposed on the barrier layer 230, and a metal anode 600 and a trench structure 700 disposed between the gate structure 400 and the drain 500.

[0057] Specifically, when the metal anode 600 is outside the trench structure 700 and the depth of the trench structure 700 is less than the thickness of the barrier layer 230, the sidewall of the metal anode 600 away from the gate structure 400 contacts the sidewall of the trench structure 700 near the gate structure 400; the metal anode 600 is disposed on the outside of the trench structure 700 on the side near the gate structure 400, and a portion of the metal anode 600 in the first direction away from the sidewall of the gate structure 400 is in the same plane in the third direction as the sidewall of the trench structure 700 near the gate structure 400, that is, in the same plane in the vertical direction; another portion of the metal anode 600 in the first direction covers a portion of the barrier layer 230, and the surface of this portion of the metal anode 600 in contact with the barrier layer 230 forms a Schottky contact with the barrier layer 230.

[0058] In some embodiments, a portion of the metal anode 600 in the second direction may cover the barrier layer 230, and another portion of the metal anode 600 in the second direction may cover a portion of the trench structure 700.

[0059] See Figure 8 , Figure 9 , Figure 8 yes Figure 7 Front view of the second-direction section. Figure 9 yes Figure 7 Rear view of the second-direction section.

[0060] Please see Figure 10 , Figure 10 This is a schematic diagram of the sixth embodiment of the gallium nitride semiconductor device in this application.

[0061] like Figure 10 As shown, the gallium nitride semiconductor device includes a semiconductor substrate 100, a buffer layer 210, a channel layer 220, a barrier layer 230, a source 300, a gate structure 400 and a drain 500 disposed on the barrier layer 230, and a metal anode 600 and a trench structure 700 disposed between the gate structure 400 and the drain 500.

[0062] Specifically, when the metal anode 600 is outside the trench structure 700, and the depth of the trench structure 700 is equal to the thickness of the barrier layer 230, the sidewall of the metal anode 600 away from the gate structure 400 contacts the sidewall of the trench structure 700 near the gate structure 400; the metal anode 600 is disposed on the outside of the trench structure 700 on the side near the gate structure 400, and a portion of the metal anode 600 in the first direction away from the sidewall of the gate structure 400 is in the same plane in the third direction as the sidewall of the trench structure 700 near the gate structure 400, that is, in the same plane in the vertical direction; another portion of the metal anode 600 in the first direction covers a portion of the barrier layer 230, and the surface of this portion of the metal anode 600 in contact with the barrier layer 230 forms a Schottky contact with the barrier layer 230.

[0063] In some embodiments, a portion of the metal anode 600 in the second direction may cover the barrier layer 230, and another portion of the metal anode 600 in the second direction may cover a portion of the trench structure 700.

[0064] Please see Figure 11 , Figure 11 This is a schematic diagram of the structure of the seventh embodiment of the gallium nitride semiconductor device in this application.

[0065] like Figure 11 As shown, the gallium nitride semiconductor device includes a semiconductor substrate 100, a buffer layer 210, a channel layer 220, a barrier layer 230, a source 300, a gate structure 400 and a drain 500 disposed on the barrier layer 230, a metal anode 600 disposed between the gate structure 400 and the drain 500, and a plurality of trench structures 700, wherein the plurality of trench structures 700 are arranged in a comb-finger pattern.

[0066] The multiple trench structures 700 arranged in a comb-like pattern spatially separate the withstand voltage structure and the conduction structure, dividing them into trench structure parts and non-trench structure parts. The two-dimensional electron gas in the non-trench structure parts is unaffected, while the two-dimensional electron gas in the trench structure parts is reduced or even depleted. This reduces the concentration of two-dimensional electron gas near the metal anode 600, thereby reducing the electric field strength near the metal anode 600 during withstand voltage testing and improving the withstand voltage capability of the gallium nitride semiconductor device. Furthermore, the metal anode 600 within the trench structure is mainly used to regulate the electric field, while the metal anode 600 outside the trench is mainly used for conduction.

[0067] Specifically, taking as an example where some metal anodes 600 are located within trench structures 700, and the depth of trench structures 700 is less than the thickness of barrier layer 230, and there are four trench structures 700: the trench structures 700 include a first trench structure 710, a second trench structure 720, a third trench structure 730, and a fourth trench structure 740; the first trench structure 710, the second trench structure 720, the third trench structure 730, and the fourth trench structure 740 are disposed on the surface of barrier layer 230 away from channel layer 220, and are arranged in a comb-like pattern, that is, equally spaced, and perpendicular to gate structure 400; the metal anodes 600 are disposed on the side of trench structure 700 close to gate structure 400, that is, the metal anodes 600 span the first trench structure 710, the second trench structure 720, the third trench structure 730, and the fourth trench structure 740 in the first direction. The metal anode 600 contacts the sidewall of the gate structure 400 near the gate structure 400. A portion of the metal anode 600 in the first direction covers a portion of the trench structure 700, and another portion covers a portion of the barrier layer. That is, part of the metal anode 600 is inside the trench structure 700, and part is outside the trench structure 700. The surface of the metal anode 600 outside the trench structure 700 that contacts the barrier layer 230 forms a Schottky contact with the barrier layer. The surface of the metal anode 600 inside the trench structure 700 that contacts the channel layer 220 is on the same horizontal plane as the bottom surface of the trench structure 700.

[0068] In some embodiments, the spacing between two adjacent trench structures 700 is not greater than the width of the trench structure 700 in the first direction; for example, the spacing between two adjacent trench structures 700 may be between 50nm and 5um, and the width of the trench structure 700 in the first direction may be between 100nm and 5um.

[0069] In some embodiments, along the first direction, the plurality of trench structures occupy 10%-90% of the surface of the barrier layer away from the channel layer; for example, in the case of two trench structures, along the first direction, one trench structure occupies 5% of the surface of the barrier layer away from the channel layer, the other trench structure occupies 5% of the surface of the barrier layer away from the channel layer, and the non-trench structure portion occupies 90%; or in the case of three trench structures, one trench structure occupies 30% of the surface of the barrier layer away from the channel layer, the middle trench structure occupies 30% of the surface of the barrier layer away from the channel layer, the other trench structure occupies 30% of the surface of the barrier layer away from the channel layer, and the non-trench structure portion occupies 10%. It is understood that, along the first direction, the total proportion of all trench structures on the surface of the barrier layer away from the channel layer is 10%-90%.

[0070] In this embodiment, on the one hand, a metal anode is disposed between the gate structure 400 and the drain 500, and the metal anode 600 and the drain 500 form a reverse freewheeling diode, so that the HEMT can achieve reverse conduction, and the reverse freewheeling diode and the HEMT can share the two-dimensional electron gas, avoiding the introduction of additional parasitic parameters, saving device area, and reducing cost. On the other hand, by distributing multiple trench structures 700 at intervals on the barrier layer surface of the HEMT, and distributing the metal anode 600 on the side of the trench structure 700 close to the gate structure 400, the two-dimensional electron gas under the trench structure 700 is reduced or even depleted, modulating the electric field distribution of the channel, improving the device breakdown voltage, and improving the electric field concentration effect near the reverse freewheeling diode, weakening the Schottky barrier reduction effect, and reducing the leakage current of the device.

[0071] In one embodiment, the device further includes a chip that comprises the gallium nitride semiconductor device described above.

[0072] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A gallium nitride semiconductor device, characterized in that, include: Semiconductor substrate; The semiconductor substrate has a first surface; A multilayer semiconductor layer is disposed on the first surface; wherein, at least one trench structure is formed on the surface of the semiconductor layer away from the semiconductor substrate; A source, a gate structure, and a drain are disposed at intervals on the surface of the semiconductor layer away from the semiconductor substrate, and the gate structure is disposed between the source and the drain. A metal anode is disposed on the surface of the semiconductor layer away from the semiconductor substrate, parallel to the first direction of the source electrode and spaced between the gate structure and the drain electrode, and the metal anode forms a Schottky contact with the semiconductor layer; In this configuration, at least one of the trench structures is disposed between the gate structure and the drain, and the metal anode is disposed on the side of the at least one trench structure near the gate structure. The other side of the at least one trench structure extends along the source to the drain in a second direction. A portion of the metal anode is disposed within the trench structure and covers only a portion of the trench structure, or the metal anode is disposed outside the trench structure. The metal anode contacts the source and the drain respectively through the semiconductor layer to form a reverse freewheeling diode.

2. The gallium nitride semiconductor device according to claim 1, characterized in that, The multilayer semiconductor layer includes a buffer layer, a channel layer, and a barrier layer stacked sequentially along a third direction; Wherein, the third direction is perpendicular to the first direction and the second direction; at least one trench structure is formed on the surface of the barrier layer away from the channel layer, the width of the trench structure in the first direction is not greater than the width of the metal anode in the first direction, and the depth of the trench structure is not greater than the thickness of the barrier layer.

3. The gallium nitride semiconductor device according to claim 2, characterized in that, The metal anode is in contact with the sidewall of the gate structure near the gate structure; Wherein, a portion of the metal anode in the first direction covers a portion of the trench structure, the surface of the metal anode in contact with the barrier layer is on the same horizontal plane as the bottom surface of the trench structure, and the sidewall of the metal anode near the gate structure is in contact with the sidewall of the trench structure near the gate structure; or The surface of the metal anode that contacts the channel layer is on the same horizontal plane as the bottom surface of the trench structure, and the sidewall of the metal anode near the gate structure contacts the sidewall of the trench structure near the gate structure; In the first direction, another portion of the metal anode covers a portion of the barrier layer, and the surface of the metal anode that contacts the barrier layer forms a Schottky contact with the barrier layer.

4. The gallium nitride semiconductor device according to claim 2, characterized in that, The sidewall of the metal anode away from the gate structure is in contact with the sidewall of the trench structure near the gate structure; Wherein, the metal anode is disposed on the exterior of the trench structure near the gate structure, and a portion of the metal anode in the first direction is away from the sidewall of the gate structure, and is on the same plane as the sidewall of the trench structure near the gate structure in the third direction; In the first direction, another portion of the metal anode covers a portion of the barrier layer, and the surface of the metal anode that contacts the barrier layer forms a Schottky contact with the barrier layer.

5. The gallium nitride semiconductor device according to claim 2, characterized in that, There are multiple trench structures, which extend along the source to the drain in a second direction on the surface of the barrier layer away from the channel layer, and the multiple trench structures are arranged in a comb-like pattern on the surface of the barrier layer away from the channel layer.

6. The gallium nitride semiconductor device according to claim 5, characterized in that, Multiple trench structures are equally spaced along the first direction on the surface of the barrier layer away from the channel layer, and the spacing between two adjacent trench structures is 50nm-5um.

7. The gallium nitride semiconductor device according to claim 5, characterized in that, In the first direction, the plurality of trench structures occupy 10%-90% of the surface of the barrier layer away from the channel layer in the first direction.

8. The gallium nitride semiconductor device according to claim 1, characterized in that, The gate structure includes a P-type gallium nitride (P-GaN) structure and a gate stacked sequentially. The P-type gallium nitride (P-GaN) structure is disposed on the surface of the semiconductor layer away from the semiconductor substrate, and the gate is disposed on the surface of the P-type gallium nitride (P-GaN) structure away from the semiconductor layer. The gate and the P-type gallium nitride (P-GaN) structure form an ohmic contact or a Schottky contact.

9. The gallium nitride semiconductor device according to claim 2, characterized in that, When the gallium nitride semiconductor device is forward-biased, the drain is at a positive voltage, the reverse freewheeling diode is in a turned-off state, and the two-dimensional electron gas in the barrier layer that is not the trench structure serves as the current circuit; when the gallium nitride semiconductor device is reverse-biased, the current reaches the drain through the two-dimensional electron gas in the barrier layer that is not the trench structure.

10. A chip, characterized in that, Includes the gallium nitride semiconductor device as described in any one of claims 1-9.

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