A GaN HEMT power device, a preparation method and a chip

Abstract

The application belongs to the technical field of semiconductors, and provides a GaN HEMT power device, a preparation method and a chip. The GaN HEMT power device comprises a semiconductor substrate, a first channel layer, a second channel layer, a first barrier layer, a second barrier layer, a cap layer, a source electrode, a drain electrode, a gate electrode, a cathode electrode, an anode electrode and a plurality of electric field adjusting units. According to the embodiment, the plurality of electric field adjusting units can form PN junctions with the second channel layer to generate a longitudinal electric field, thereby offsetting a part of two-dimensional electron gas, making the transverse electric field more uniform, and improving the reverse breakdown voltage of the body diode formed by the cathode electrode, the anode electrode and the plurality of electric field adjusting units, and further improving the reverse breakdown voltage of the GaN HEMT power device.

Description

Technical Field

[0001] This application belongs to the field of semiconductor technology, and in particular relates to a GaN HEMT power device, its fabrication method, and a chip. Background Technology

[0002] HEMT (High Electron Mobility Transistor) devices, as typical representatives of third-generation wide bandgap semiconductor materials, have a series of material performance advantages such as large bandgap, strong breakdown electric field, high electron saturation drift velocity and good chemical stability, making them a popular material for developing high-performance power electronic devices.

[0003] However, gallium nitride high electron mobility transistors (GaN HEMTs) have low breakdown voltage capability and are more prone to breakdown under high inductance application conditions because they do not have parasitic diodes, which greatly limits their application. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a GaN HEMT power device, its fabrication method, and a chip, aiming to solve the problem of low breakdown voltage in existing GaN HEMT power devices.

[0005] A first aspect of this application provides a GaN HEMT power device, the GaN HEMT power device comprising:

[0006] Semiconductor substrate;

[0007] A first channel layer and a second channel layer are both disposed on the semiconductor substrate, and the first channel layer and the second channel layer are not in contact with each other;

[0008] A first barrier layer and a second barrier layer, wherein the first barrier layer is disposed on the first channel layer and the second barrier layer is disposed on the second channel layer;

[0009] A capping layer is disposed on the first barrier layer;

[0010] The source electrode is disposed on the first channel layer and is in contact with the first side of the first barrier layer;

[0011] The drain electrode is disposed on the first channel layer and is in contact with the second side of the first barrier layer;

[0012] The gate electrode is disposed on the capping layer;

[0013] A cathode electrode is disposed on the second channel layer and is in contact with the second side of the second barrier layer;

[0014] An anode electrode is disposed on the second channel layer and is in contact with the first side of the second barrier layer;

[0015] Multiple electric field adjustment units are disposed between the cathode electrode and the anode electrode, and the multiple electric field adjustment units do not contact each other, but are all in contact with the second barrier layer, for the purpose of depleting the two-dimensional electron gas in the second channel layer.

[0016] In one embodiment, there are multiple cathode electrodes, which are respectively disposed on multiple second channel layers and respectively contact the second side of multiple second barrier layers;

[0017] The anode electrode is a plurality of electrodes, which are respectively disposed on a plurality of second channel layers and respectively contact the first side of a plurality of second barrier layers;

[0018] A plurality of electric field adjustment units are provided between each cathode unit and each anode unit, and the plurality of electric field adjustment units do not contact each other. The plurality of electric field adjustment units are in contact with the second barrier layer to deplete the two-dimensional electron gas in the second channel layer.

[0019] In one embodiment, the electric field adjustment unit is a P-type doped region located on the second barrier layer.

[0020] In one embodiment, the electric field adjustment unit is a metal field plate located on the second barrier layer.

[0021] In one embodiment, the second barrier layer includes a plurality of second barrier units, and the electric field adjustment unit is an ion implantation region; wherein the plurality of ion implantation regions and the plurality of second barrier units are spaced apart, and the plurality of ion implantation regions and the plurality of second barrier units are all disposed on the second channel layer.

[0022] In one embodiment, the width of the plurality of electric field adjustment units gradually increases from the middle region toward the cathode electrode and toward the anode electrode.

[0023] In one embodiment, the thickness of the plurality of electric field adjustment units gradually increases from the middle region toward the cathode electrode and toward the anode electrode.

[0024] In one embodiment, the doping concentration of the plurality of P-type doped regions gradually increases from the middle region toward the cathode electrode and toward the anode electrode.

[0025] In one embodiment, the width of the plurality of second barrier units gradually decreases from the middle region toward the cathode electrode and toward the anode electrode.

[0026] A second aspect of this application provides a method for fabricating a GaN HEMT power device, comprising:

[0027] A first channel layer and a second channel layer are sequentially formed on a semiconductor substrate; wherein the first channel layer and the second channel layer are not in contact with each other;

[0028] A first barrier layer is formed on the first channel layer, and a second barrier layer is formed on the second channel layer;

[0029] A capping layer is formed on the first barrier layer;

[0030] Multiple electric field adjustment units are formed, and the multiple electric field adjustment units do not contact each other, but all of the multiple electric field adjustment units are in contact with the second barrier layer, in order to deplete the two-dimensional electron gas in the second channel layer;

[0031] A source electrode and a drain electrode are formed in the first channel layer; wherein the source electrode is in contact with a first side of the first barrier layer, and the drain electrode is in contact with a second side of the first barrier layer; a gate electrode is formed on the capping layer;

[0032] A cathode electrode is formed on the second channel layer; wherein the cathode electrode is in contact with a second side of the second barrier layer; an anode electrode is formed on the second channel layer; wherein the anode electrode is in contact with a first side of the second barrier layer; wherein a plurality of electric field adjustment units are located between the cathode electrode and the anode electrode.

[0033] A third aspect of this application provides a chip including at least one GaN HEMT power device as described in any of the preceding claims; or the chip includes at least one GaN HEMT power device fabricated by the fabrication method described above.

[0034] The beneficial effects of this application embodiment compared with the prior art are as follows: This application embodiment sets up multiple electric field adjustment units, which can form a PN junction with the second channel layer to generate a longitudinal electric field, thereby canceling out part of the two-dimensional electron gas and making the transverse electric field more uniform. This improves the reverse breakdown voltage of the body diode formed by the cathode electrode, anode electrode, and multiple electric field adjustment units, and further improves the reverse breakdown voltage of GaN HEMT power devices. Attached Figure Description

[0035] Figure 1This is a top view of a GaN HEMT power device provided in one embodiment of this application;

[0036] Figure 2 This is a front view schematic diagram of a GaN HEMT power device provided in one embodiment of this application. Figure 1 ;

[0037] Figure 3 This is a schematic diagram of the structure of a GaN HEMT power device provided in one embodiment of this application. Figure 2 ;

[0038] Figure 4 This is a schematic diagram of the structure of a GaN HEMT power device provided in one embodiment of this application. Figure 1 ;

[0039] Figure 5 This is a schematic diagram of the structure of a GaN HEMT power device provided in one embodiment of this application. Figure 2 ;

[0040] Figure 6 This is a schematic diagram of the structure of a GaN HEMT power device provided in one embodiment of this application. Figure 3 ;

[0041] Figure 7 This is a schematic diagram of the fabrication steps of a GaN HEMT power device according to an embodiment of this application;

[0042] Figure 8 This is a schematic diagram of the formation of a first trench layer and a second trench layer provided in one embodiment of this application;

[0043] Figure 9 This is a schematic diagram of the formation of the first barrier layer and the second barrier layer according to an embodiment of this application;

[0044] Figure 10 This is a schematic diagram of the capping layer after it has been formed, provided in one embodiment of this application;

[0045] Figure 11 This is a schematic diagram of the electric field adjustment unit after it has been formed, according to one embodiment of this application;

[0046] Figure 12 This is a schematic diagram of the formation of a cathode electrode, an anode electrode, a gate electrode, a drain electrode, and a source electrode provided in one embodiment of this application. Detailed Implementation

[0047] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0048] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0049] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means one or more, unless otherwise explicitly specified.

[0051] In this specification, references to "one embodiment," "some embodiments," or simply "embodiment" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," "in a particular embodiment," and "in a particular application," appearing in various parts of this specification, do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. Furthermore, in one or more embodiments, specific features, structures, or characteristics may be combined in any suitable manner.

[0052] HEMT (High Electron Mobility Transistor) devices, as typical representatives of third-generation wide bandgap semiconductor materials, have a series of material performance advantages such as large bandgap, strong breakdown electric field, high electron saturation drift velocity and good chemical stability, making them a popular material for developing high-performance power electronic devices.

[0053] However, gallium nitride high electron mobility transistors (GaN HEMTs) have low breakdown voltage capability and are more prone to breakdown under high inductance application conditions because they do not have parasitic diodes, which greatly limits their application.

[0054] To address the aforementioned technical problems, this application provides a GaN HEMT power device, as shown in the reference. Figure 1 , Figure 2 , Figure 3 As shown, the GaN HEMT power device includes: a semiconductor substrate 10, a first channel layer 20, a second channel layer 30, a first barrier layer 40, a second barrier layer 50, a capping layer 60, a cathode electrode 70, an anode electrode 80, multiple electric field adjustment units 90, a source electrode 100, a drain electrode 110, and a gate electrode 120.

[0055] Specifically, the first channel layer 20 and the second channel layer 30 are both disposed on the semiconductor substrate 10, and the first channel layer 20 and the second channel layer 30 are not in contact with each other. A first barrier layer 40 is disposed on the first channel layer 20, and a second barrier layer 50 is disposed on the second channel layer 30. A capping layer 60 is disposed on the first barrier layer 40. A source electrode 100 is disposed on the first channel layer 20, and the source electrode 100 is in contact with a first side of the first barrier layer 40. A drain electrode 110 is disposed on the first channel layer 20, and the drain electrode 110 is in contact with a second side of the first barrier layer 40. A gate electrode 120 is disposed on the capping layer 60. A cathode electrode 70 is disposed on the second channel layer 30, and the cathode electrode 70 is in contact with a second side of the second barrier layer 50. An anode electrode 80 is disposed on the second channel layer 30, and the anode electrode 80 is in contact with a first side of the second barrier layer 50. Multiple electric field adjustment units 90 are disposed between the cathode electrode 70 and the anode electrode 80, and the multiple electric field adjustment units 90 do not contact each other, but are in contact with the second barrier layer 50. The multiple electric field adjustment units 90 are used to deplete the two-dimensional electron gas in the second channel layer 30.

[0056] In this embodiment, both the first channel layer 20 and the second channel layer 30 are disposed on the semiconductor substrate 10, and the first channel layer 20 and the second channel layer 30 do not contact each other. It is understood that the first channel layer 20 and the second channel layer 30 are located on the same horizontal plane, and the first channel layer 20 and the second channel layer 30 are made of the same material. The first channel layer 20 and the second channel layer 30 can be integrally formed on the semiconductor substrate 10 in one step, and then sheared to ensure that the first channel layer 20 and the second channel layer 30 do not contact each other. Alternatively, an insulating material can be placed between the first channel layer 20 and the second channel layer 30 to ensure that they do not contact each other. By ensuring that the first channel layer 20 and the second channel layer 30 do not contact each other, they can avoid interfering with each other, reducing mutual interference between the first channel layer 20 and the second channel layer 30, allowing the first channel layer 20 and the second channel layer 30 to perform their respective functions, and improving the stability of the GaN HEMT power device.

[0057] In this embodiment, since existing GaN HEMT power devices generally lack parasitic diodes, their breakdown voltage capability is low under high inductance application conditions, making them prone to breakdown and severely limiting their applications. By setting the cathode electrode 70 on the second channel layer 30 and contacting the second side of the second barrier layer 50, and the anode electrode 80 on the second channel layer 30 and contacting the first side of the second barrier layer 50, a diode function can be achieved, serving as the body diode of the GaN HEMT power device. The cathode electrode 70 can be connected in series with the drain electrode 110, or the anode electrode 80 can be connected in series with the source electrode 100. Specifically, in different application scenarios, the cathode electrode 70 can be connected to the drain electrode 110, or the anode electrode 80 can be connected to the source electrode 100. It should be noted that only one implementation method can be selected: either connecting the cathode electrode 70 to the drain electrode 110 or connecting the anode electrode 80 to the source electrode 100. For example, when the cathode electrode 70 is connected to the drain electrode 110, the anode electrode 80 cannot be connected to the source electrode 100, and vice versa. The purpose of this arrangement is to connect the body diode formed by the cathode electrode 70, anode electrode 80, and multiple electric field adjustment units 90, etc., in series with either the drain electrode 110 or the source electrode 100, rather than in parallel.

[0058] In this embodiment, multiple electric field adjustment units 90 are in contact with the second barrier layer 50 to deplete the two-dimensional electron gas (2DEG) in the second channel layer 30. Specifically, when the GaN HEMT power device is operating, it generates corresponding two-dimensional electron gas in the first channel layer 20 and the second channel layer 30. Although this reduces the on-resistance, it also makes the breakdown voltage of the power device smaller. This embodiment of the application sets multiple electric field adjustment units 90, which can form a PN junction with the second channel layer 30 to generate a longitudinal electric field, thereby canceling out part of the two-dimensional electron gas and making the lateral electric field more uniform. This improves the reverse breakdown voltage of the body diode formed by the cathode electrode 70, the anode electrode 80, and the multiple electric field adjustment units 90, and further improves the reverse breakdown voltage of the GaN HEMT power device.

[0059] In one embodiment, the first channel layer 20 and the second channel layer 30 are GaN.

[0060] In this embodiment, the first channel layer 20 and the second channel layer 30 can both be made of gallium nitride material, for example, by depositing gallium nitride material on the semiconductor substrate 10 or by epitaxially growing gallium nitride material, and their thickness and width are the same.

[0061] In one embodiment, the first barrier layer 40 and the second barrier layer 50 are AlGaN.

[0062] In this embodiment, the first barrier layer 40 and the second barrier layer 50 can both be made of aluminum gallium nitride (ANU) material. For example, the first barrier layer 40 is formed by depositing ANU material on the first channel layer 20 or by epitaxially growing ANU material, and the second barrier layer 50 is formed by depositing ANU material on the second channel layer 30 or by epitaxially growing ANU material.

[0063] In one embodiment, the capping layer 60 is P-GaN.

[0064] In this embodiment, P-GaN is formed by doping GaN with a p-type dopant, wherein the p-type dopant can be boron, gallium, aluminum, etc.

[0065] In one embodiment, the anode electrode 80 is made of Schottky metal and the cathode electrode 70 is made of ohmic metal.

[0066] In one embodiment, the Schottky metal can be a layer of platinum, gold, silver, or a conductive semiconductor layer, etc. The ohmic metal is a combination of Ti, Al, Ti, and Au materials.

[0067] In a specific application, Schottky metal is a combination of Ni and Au materials.

[0068] In one embodiment, the thicknesses of the ohmic metals Ti, Al, Ti, and Au are 15 nm, 250 nm, 50 nm, and 150 nm, respectively, and the thicknesses of the Schottky metals Ni and Au are 70 nm and 30 nm, respectively.

[0069] In this embodiment, by setting the anode electrode 80 to Schottky metal, the anode is a Schottky contact, which can provide a higher Schottky barrier height. By setting the thickness of Ni and Au in the Schottky metal to 70nm and 30nm respectively, the leakage current of the anode electrode 80 is further reduced, a higher forward threshold voltage is provided, and the overall performance of the GaN HEMT power device is improved.

[0070] In one embodiment, there may be multiple cathode electrodes 70, each disposed on a plurality of second channel layers 30 and respectively contacting a second side of a plurality of second barrier layers 50. There may also be multiple anode electrodes 80, each disposed on a plurality of second channel layers 30 and respectively contacting a first side of a plurality of second barrier layers 50. Multiple electric field adjustment units 90 are provided between each cathode unit and each anode unit, and these multiple electric field adjustment units 90 are not in contact with each other. Each of the multiple electric field adjustment units 90 is in contact with a corresponding second barrier layer 50, used to deplete the two-dimensional electron gas in the second channel layer 30.

[0071] In this embodiment, there are multiple cathode electrodes 70 and multiple anode electrodes 80, and multiple electric field adjustment units 90 are provided between each cathode electrode 70 and anode electrode 80. Each cathode and anode, along with its corresponding multiple electric field adjustment units 90, constitutes a body diode. Multiple cathode electrodes 70 and multiple anode electrodes 80 can form multiple body diodes, which can be connected in parallel or series to adjust the voltage and high current withstand performance of the GaN HEMT power device. For example, when multiple body diodes are connected in parallel, the high current withstand performance of the GaN HEMT power device can be adjusted. For example, when multiple body diodes are connected in series, the high voltage withstand performance of the GaN HEMT power device can be adjusted. This operation increases the voltage and current withstand capabilities of the GaN HEMT power device, expanding its application scenarios.

[0072] In one embodiment, reference Figure 3 As shown, the electric field adjustment unit 90 is a P-type doped region, which is located on the second barrier layer 50.

[0073] In this embodiment, the P-type doped region is P-GaN. When the GaN HEMT power device is operating, it generates a corresponding two-dimensional electron gas in the first channel layer 20 and the second channel layer 30. Although this reduces the on-resistance, it also results in a lower breakdown voltage of the power device. By setting the electric field adjustment unit 90 as a P-type doped region, which is located on the second barrier layer 50 and is set as P-GaN, multiple P-type doped regions can form a PN junction with the second channel layer 30, generating a vertical electric field. This cancels out some of the two-dimensional electron gas, making the lateral electric field more uniform. This improves the reverse breakdown voltage of the body diode formed by the cathode electrode 70, anode electrode 80, and multiple electric field adjustment units 90, further increasing the reverse breakdown voltage of the GaN HEMT power device.

[0074] In one embodiment, reference Figure 3 As shown, the electric field adjustment unit 90 is a metal field plate, which is located on the second barrier layer 50.

[0075] In this embodiment, the metal field plate can be any one of gold, silver, copper, aluminum, platinum, etc. When the GaN HEMT power device is in operation, it generates a corresponding two-dimensional electron gas in the first channel layer 20 and the second channel layer 30. Although this reduces the on-resistance, it also makes the breakdown voltage of the power device smaller. By setting the electric field adjustment unit 90 as a metal field plate, the metal field plate is located on the second barrier layer 50, and the metal field plate can be any one of gold, silver, copper, aluminum, platinum, etc., so that multiple metal field plates can form a PN junction with the second channel layer 30, generating a vertical electric field, thereby canceling out part of the two-dimensional electron gas and making the lateral electric field more uniform. This improves the reverse breakdown voltage of the body diode formed by the cathode electrode 70, anode electrode 80, and multiple electric field adjustment units 90, and further improves the reverse breakdown voltage of the GaN HEMT power device.

[0076] In one embodiment, reference Figure 4 As shown, the second barrier layer 50 includes a plurality of second barrier units 51, and the electric field adjustment unit 90 is an ion implantation region; wherein, the plurality of ion implantation regions and the plurality of second barrier units 51 are spaced apart, and the plurality of ion implantation regions and the plurality of second barrier units 51 are all disposed on the second channel layer 30.

[0077] In this embodiment, when the electric field adjustment unit 90 is an ion implantation region, multiple ion implantation regions and multiple second barrier units 51 are spaced apart, and both the multiple ion implantation regions and multiple second barrier units 51 are disposed on the second channel layer 30. At this time, fluorine ions or hydrogen ions are implanted in the multiple ion implantation regions. When the GaN HEMT power device is in operation, it generates a corresponding two-dimensional electron gas in the first channel layer 20 and the second channel layer 30. Although this reduces the on-resistance, it also makes the breakdown voltage of the power device smaller. By setting multiple ion implantation regions and multiple second barrier units 51 spaced apart, and both the multiple ion implantation regions and multiple second barrier units 51 are disposed on the second channel layer 30, fluorine ions or hydrogen ions are implanted in the multiple ion implantation regions. This allows the multiple ion implantation regions and the second channel layer 30 to form a PN junction, generating a longitudinal electric field, thereby canceling out part of the two-dimensional electron gas, making the transverse electric field more uniform, and further improving the reverse breakdown voltage of the GaN HEMT power device.

[0078] In one embodiment, the width of the plurality of electric field adjustment units 90 gradually increases from the middle region toward the cathode electrode 70 and toward the anode electrode 80.

[0079] For details, please refer to Figure 5 As shown, the width of the multiple electric field adjustment units 90 gradually increases from the middle region towards the left and right sides. It can be understood that the electric field adjustment units 90 closer to the cathode electrode 70 and anode electrode 80 have larger widths, while those farther away have smaller widths. For example, W1 and W2 represent the widths of the electric field adjustment units 90 closer to the cathode electrode 70, and W3 and W4 represent the widths of the electric field adjustment units 90 closer to the anode electrode 80; where W1 > W2 and W3 > W4. This is because when the GaN HEMT power device is in operation, the electric field spikes near the cathode electrode 70 and anode electrode 80 are high. By setting the electric field adjustment units 90 closer to the cathode electrode 70 and anode electrode 80 to have larger widths, more of the two-dimensional electron gas in the second channel layer 30 can be depleted, resulting in a more uniform lateral electric field. This can better reduce the electric field spikes at the cathode electrode 70 and anode electrode 80, further improving the reverse breakdown voltage of the GaN HEMT power device.

[0080] In one embodiment, the thickness of the plurality of electric field adjustment units 90 gradually increases from the middle region toward the cathode electrode 70 and toward the anode electrode 80.

[0081] In this embodiment, reference Figure 6As shown, the thickness of the multiple electric field adjustment units 90 gradually increases from the middle region towards the left and right sides. It can be understood that the electric field adjustment units 90 closer to the cathode electrode 70 and anode electrode 80 have a larger thickness, while those farther away have a smaller thickness. For example, H1 and H2 represent the thickness of the electric field adjustment units 90 near the cathode electrode 70, and H3 and H4 represent the thickness of the electric field adjustment units 90 near the anode electrode 80; where H1 > H2 and H3 > H4. This is because when the GaN HEMT power device is in operation, the electric field spikes near the cathode electrode 70 and anode electrode 80 are high. By making the electric field adjustment units 90 closer to the cathode electrode 70 and anode electrode 80 thicker, more of the two-dimensional electron gas in the second channel layer 30 can be depleted, resulting in a more uniform lateral electric field. This can better reduce the electric field spikes at the cathode electrode 70 and anode electrode 80, further improving the reverse breakdown voltage of the GaN HEMT power device.

[0082] In one embodiment, reference Figure 4 As shown, the doping concentration of the multiple P-type doped regions gradually increases from the middle region toward the cathode electrode 70 and the anode electrode 80.

[0083] In this embodiment, the doping concentration of the multiple P-type doped regions gradually increases from the middle region towards the cathode electrode 70 and the anode electrode 80. It is understood that the doping concentration of the P-type doped regions closer to the cathode electrode 70 and the anode electrode 80 is higher, while the doping concentration of the P-type doped regions farther away from the cathode electrode 70 and the anode electrode 80 is lower. This is because when the GaN HEMT power device is in operation, the electric field spikes near the cathode electrode 70 and the anode electrode 80 are high. By setting a higher doping concentration in the P-type doped regions closer to the cathode electrode 70 and the anode electrode 80, more of the two-dimensional electron gas in the second channel layer 30 can be depleted, resulting in a more uniform lateral electric field. This can better reduce the electric field spikes at the cathode electrode 70 and the anode electrode 80, further improving the reverse breakdown voltage of the GaN HEMT power device.

[0084] In one embodiment, reference Figure 4 As shown, the width of the multiple second barrier units 51 gradually decreases from the middle region toward the cathode electrode 70 and the anode electrode 80.

[0085] In this embodiment, reference Figure 4As shown, multiple electric field adjustment units 90 and multiple second barrier units 51 are spaced apart, and both are located on the second channel layer 30. It is understood that the multiple second barrier units 51 and multiple electric field adjustment units 90 are spaced apart, and adjacent second barrier units 51 are in contact with the electric field adjustment units 90. When the width of the multiple second barrier units 51 gradually increases from the middle region towards the cathode electrode 70 and the anode electrode 80, the distance between adjacent electric field adjustment units 90 becomes larger. For example, W5, W6, and W7 represent the widths of the second barrier units 51 that are increasingly farther from the middle region, where W5 > W6 > W7. It is understood that the spacing between the electric field adjustment units 90 near the cathode electrode 70 and the anode electrode 80 is smaller; in other words, the electric field adjustment units 90 near the cathode electrode 70 and the anode electrode 80 are arranged more densely. This operation can deplete more of the two-dimensional electron gas in the second channel layer 30 near the cathode electrode 70 and the anode electrode 80, making the lateral electric field more uniform. This can better reduce the electric field spikes at the cathode electrode 70 and the anode electrode 80, and further improve the reverse breakdown voltage of the GaN HEMT power device.

[0086] In one embodiment, the spacing between adjacent electric field conditioning units 90 gradually decreases from the central region toward the cathode electrode 70 and anode electrode 80. It is understood that the spacing between adjacent electric field conditioning units 90 near the cathode electrode 70 and anode electrode 80 is smaller, while the spacing between adjacent electric field conditioning units 90 near the central region is larger. In this embodiment, it should be noted that the central region refers to the midpoint between the anode electrode 80 and the cathode electrode 70. This operation allows for greater depletion of the two-dimensional electron gas in the second channel layer 30 near the cathode electrode 70 and anode electrode 80, resulting in a more uniform lateral electric field. This better reduces electric field spikes at the cathode electrode 70 and anode electrode 80, further improving the reverse breakdown voltage of the GaN HEMT power device.

[0087] In one embodiment, multiple electric field adjustment units 90 are symmetrically arranged.

[0088] In this embodiment, specifically, multiple electric field adjustment units 90 are symmetrically arranged from the central region towards the cathode electrode 70 and towards the anode electrode 80. For example, the thickness, width, and concentration of the electric field adjustment units 90 near the anode electrode 80 are the same as those near the cathode electrode 70. This operation ensures that the electric field adjustment units 90 uniformly deplete the two-dimensional electron gas in the second channel layer 30 near the cathode electrode 70 and the anode electrode 80, resulting in a more uniform lateral electric field. This better reduces electric field spikes at the cathode electrode 70 and the anode electrode 80, further improving the reverse breakdown voltage of the GaN HEMT power device, and thus making the GaN HEMT power device more stable.

[0089] This application also provides a method for fabricating a GaN HEMT power device, referencing... Figure 7 As shown, it includes steps S10 to S60.

[0090] Step S10: Reference Figure 8 As shown, a first channel layer 20 and a second channel layer 30 are sequentially formed on a semiconductor substrate 10; wherein the first channel layer 20 and the second channel layer 30 are not in contact with each other.

[0091] In this embodiment, selective etching is performed on the semiconductor substrate 10 to etch out the positions of the first channel layer 20 and the second channel layer 30, respectively. Then, the corresponding semiconductor materials are filled in the corresponding positions of the first channel layer 20 and the second channel layer 30. For example, GaN material is filled in the regions of the first channel layer 20 and the second channel layer 30.

[0092] In one specific application, the semiconductor substrate 10 is a sapphire substrate.

[0093] Step S20: Reference Figure 9 As shown, a first barrier layer 40 is formed on the first channel layer 20, and a second barrier layer 50 is formed on the second channel layer 30.

[0094] In this embodiment, a first barrier layer 40 is epitaxially formed on the first channel layer 20, and a second barrier layer 50 is epitaxially formed on the second channel layer 30, wherein the first barrier layer 40 and the second barrier layer 50 are filled with AlGaN material.

[0095] Step S30: Reference Figure 10 As shown, a capping layer 60 is formed on the first barrier layer 40.

[0096] In this embodiment, the capping layer 60 is made of P-GaN.

[0097] Step S40: Reference Figure 11As shown, multiple electric field adjustment units 90 are formed, and the multiple electric field adjustment units 90 do not contact each other. All multiple electric field adjustment units 90 are in contact with the second barrier layer 50 to deplete the two-dimensional electron gas in the second channel layer 30.

[0098] In this embodiment, multiple electric field adjustment units 90 can be formed by etching according to different application needs. Because the first channel layer 20 and the second channel layer 30 will generate corresponding two-dimensional electron gas, which reduces the on-resistance but also makes the breakdown voltage of the power device smaller. By setting the electric field adjustment units 90, multiple electric field adjustment units 90 can form a PN junction with the second channel layer 30 to generate a vertical electric field, thereby canceling out part of the two-dimensional electron gas and making the lateral electric field more uniform. This will improve the reverse breakdown voltage of the body diode formed by the cathode electrode 70, the anode electrode 80, and the multiple electric field adjustment units 90, and further improve the reverse breakdown voltage of the GaN HEMT power device.

[0099] Step S50: Reference Figure 12 As shown, a source electrode 100 and a drain electrode 110 are formed in the first channel layer 20; wherein the source electrode 100 is in contact with a first side of the first barrier layer 40, and the drain electrode 110 is in contact with a second side of the first barrier layer 40; a gate electrode 120 is formed on the capping layer 60.

[0100] In a specific application, a mask is used to determine the shape of the source electrode 100, drain electrode 110, and gate electrode 120, and metal is deposited on the mask to form the source electrode 100, drain electrode 110, and gate electrode 120.

[0101] Step S60: Reference Figure 12 As shown, a cathode electrode 70 is formed on the second channel layer 30; wherein the cathode electrode 70 is in contact with the second side of the second barrier layer 50; an anode electrode 80 is formed on the second channel layer 30; wherein the anode electrode 80 is in contact with the first side of the second barrier layer 50; wherein a plurality of electric field adjustment units 90 are located between the cathode electrode 70 and the anode electrode 80.

[0102] In one specific application, a mask is used to determine the shape of the cathode electrode 70 and the anode electrode 80, and metal is deposited on the mask to form the cathode electrode 70 and the anode electrode 80.

[0103] In one embodiment, the anode electrode 80 is made of Schottky metal and the cathode electrode 70 is made of ohmic metal.

[0104] In one embodiment, the Schottky metal can be a layer of platinum, gold, silver, or a conductive semiconductor layer, etc. The ohmic metal is a combination of Ti, Al, Ti, and Au materials.

[0105] In a specific application, Schottky metal is a combination of Ni and Au materials.

[0106] In one embodiment, the thicknesses of the ohmic metals Ti, Al, Ti, and Au are 15 nm, 250 nm, 50 nm, and 150 nm, respectively, and the thicknesses of the Schottky metals Ni and Au are 70 nm and 30 nm, respectively.

[0107] In this embodiment, by setting the anode electrode 80 to Schottky metal, the anode is a Schottky contact, which can provide a higher Schottky barrier height. By setting the thickness of Ni and Au in the Schottky metal to 70nm and 30nm respectively, the leakage current of the anode electrode 80 is further reduced, a higher forward threshold voltage is provided, and the overall performance of the GaN HEMT power device is improved.

[0108] This application also provides a chip comprising at least one GaN HEMT power device as described above; or a chip comprising at least one GaN HEMT power device fabricated by the fabrication method described above.

[0109] In this embodiment, the chip includes a source terminal, a drain terminal, and a gate terminal, and also includes at least one GaN HEMT power device. Since the GaN HEMT power device includes multiple electric field adjustment units 90, and each of the multiple electric field adjustment units 90 is in contact with the second barrier layer 50, the multiple electric field adjustment units 90 are used to deplete the two-dimensional electron gas in the second channel layer 30, which can improve the breakdown voltage of the GaN HEMT power device, thereby enabling the chip to be used for higher breakdown voltages.

[0110] In one embodiment, when the cathode electrode 70 is connected in series with the drain electrode 110, the drain terminal of the chip is connected to the anode electrode 80 through a via, the source terminal of the chip is connected to the source electrode 100 of the GaN HEMT power device through a via, and the source terminal of the chip is connected to the gate electrode 120. When the anode electrode 80 is connected in series with the source electrode 100, the source terminal of the chip is connected to the cathode electrode 70 through a via, the drain terminal of the chip is connected to the drain electrode 110 through a via, and the source terminal of the chip is connected to the gate electrode 120. Therefore, in general, there are no devices below the source and drain terminals of a chip. However, the design of this application can increase the chip's breakdown voltage while increasing space requirements. Furthermore, this application can manufacture the GaN HEMT power device without using an additional photomask, avoiding cumbersome manufacturing processes.

[0111] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0112] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A GaN HEMT power device, characterized in that, The GaN HEMT power device includes: Semiconductor substrate; A first channel layer and a second channel layer are both disposed on the semiconductor substrate, and the first channel layer and the second channel layer are not in contact with each other; A first barrier layer and a second barrier layer, wherein the first barrier layer is disposed on the first channel layer and the second barrier layer is disposed on the second channel layer; A capping layer is disposed on the first barrier layer; The source electrode is disposed on the first channel layer and is in contact with the first side of the first barrier layer; The drain electrode is disposed on the first channel layer and is in contact with the second side of the first barrier layer; The gate electrode is disposed on the capping layer; A cathode electrode is disposed on the second channel layer and is in contact with the second side of the second barrier layer; An anode electrode is disposed on the second channel layer and is in contact with the first side of the second barrier layer; Multiple electric field adjustment units are disposed between the cathode electrode and the anode electrode, and the multiple electric field adjustment units do not contact each other. The multiple electric field adjustment units are all in contact with the second barrier layer to deplete the two-dimensional electron gas in the second channel layer. The width of the multiple electric field adjustment units gradually increases from the middle region toward the cathode electrode and the anode electrode.

2. The GaN HEMT power device as described in claim 1, characterized in that, The cathode electrode is a plurality of electrodes, which are respectively disposed on a plurality of second channel layers and respectively contact the second side of the plurality of second barrier layers; The anode electrode is a plurality of electrodes, which are respectively disposed on a plurality of second channel layers and respectively contact the first side of a plurality of second barrier layers; A plurality of electric field adjustment units are provided between each of the cathode electrodes and each of the anode electrodes, and the plurality of electric field adjustment units do not contact each other. The plurality of electric field adjustment units are in contact with the second barrier layer to deplete the two-dimensional electron gas in the second channel layer.

3. The GaN HEMT power device as described in claim 1, characterized in that, The electric field adjustment unit is a P-type doped region, which is located on the second barrier layer.

4. The GaN HEMT power device as described in claim 1, characterized in that, The electric field adjustment unit is a metal field plate, which is located on the second barrier layer.

5. The GaN HEMT power device as described in claim 1, characterized in that, The second barrier layer includes a plurality of second barrier units, and the electric field adjustment unit is an ion implantation region; wherein, the plurality of ion implantation regions and the plurality of second barrier units are spaced apart, and the plurality of ion implantation regions and the plurality of second barrier units are all disposed on the second channel layer.

6. The GaN HEMT power device according to any one of claims 1-5, characterized in that, The thickness of the plurality of electric field adjustment units gradually increases from the middle region toward the cathode electrode and toward the anode electrode.

7. The GaN HEMT power device as described in claim 3, characterized in that, The doping concentration of the multiple P-type doped regions gradually increases from the middle region toward the cathode electrode and toward the anode electrode.

8. A method for fabricating a GaN HEMT power device as described in any one of claims 1-7, characterized in that, include: A first channel layer and a second channel layer are sequentially formed on a semiconductor substrate; wherein the first channel layer and the second channel layer are not in contact with each other; A first barrier layer is formed on the first channel layer, and a second barrier layer is formed on the second channel layer; A capping layer is formed on the first barrier layer; Multiple electric field adjustment units are formed, and the multiple electric field adjustment units do not contact each other, but all of the multiple electric field adjustment units are in contact with the second barrier layer, in order to deplete the two-dimensional electron gas in the second channel layer; A source electrode and a drain electrode are formed in the first channel layer; wherein the source electrode is in contact with a first side of the first barrier layer, and the drain electrode is in contact with a second side of the first barrier layer; a gate electrode is formed on the capping layer; A cathode electrode is formed on the second channel layer; wherein the cathode electrode is in contact with a second side of the second barrier layer; an anode electrode is formed on the second channel layer; wherein the anode electrode is in contact with a first side of the second barrier layer; wherein a plurality of electric field adjustment units are located between the cathode electrode and the anode electrode.

9. A chip, characterized in that, It includes at least one GaN HEMT power device as described in any one of claims 1-7; or the chip includes at least one GaN HEMT power device prepared by the preparation method described in claim 8.

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