A composite dielectric structure of a gallium nitride electronic device and a preparation method thereof

Abstract

A composite dielectric structure of a gallium nitride electronic device includes: a low interface state dielectric insertion layer and a high breakdown electric field dielectric layer, wherein the low interface state dielectric insertion layer is grown on the surface of the gallium nitride electronic device, and the high breakdown electric field dielectric layer is grown on the low interface state dielectric insertion layer. The present disclosure also provides a method for preparing a composite dielectric structure, including: placing the gallium nitride electronic device in a machine, adjusting the temperature of the machine to a first preset temperature, adjusting the power to a first preset power, using plasma to clean the surface of the gallium nitride electronic device, adjusting the temperature of the machine to a second preset temperature, adjusting the power to a second preset power, growing a low interface state dielectric insertion layer on the surface of the gallium nitride electronic device, adjusting the temperature of the machine to a third preset temperature, adjusting the power to a third preset power, and growing a high breakdown electric field dielectric layer on the low interface state dielectric insertion layer. The present disclosure can effectively solve the problem of surface interface defects of gallium nitride electronic devices.

Description

Technical Field

[0001] The present disclosure relates to the technical field of semiconductor devices, and in particular to a composite dielectric structure of a gallium nitride electronic device and a preparation method thereof. Background Art

[0002] Gallium nitride (GaN)-based metal-insulator-semiconductor high electron mobility transistor (MIS / MOS-HEMT) has excellent characteristics such as high output power density, high frequency and high voltage, high temperature resistance, and radiation resistance. It has great application potential in application fields such as GaN-based power electronic devices and microwave devices.

[0003] However, the surface interface problem of GaN materials has not been systematically solved since the early stage of research. From the current mainstream level of interface state research, SiN X The interface state density between dielectrics such as SiO2 and Al2O3 and (Al)GaN is still at 10 12 -10 13 cm -2 The interface state density of power electronic devices is 10 12 cm -2 The threshold voltage of the microwave device will drift more than 2V, which greatly increases the difficulty of device practical application and reliability risk. 12 cm -2 If the surface passivation process is of the order of magnitude (equivalent to the density of the two-dimensional electron gas), the current collapse caused by surface defects is difficult to effectively suppress under high fields, especially for millimeter-wave devices, resulting in severe compression of the dynamic load line and deterioration of device power and PAE. Therefore, if the interface state problem cannot be effectively solved as soon as possible, it will become a bottleneck restricting the further improvement of the performance and reliability of power electronic devices and microwave devices, affecting the entire process of GaN practical application. Summary of the invention

[0004] The present invention provides a composite dielectric structure of a gallium nitride electronic device and a preparation method thereof, so as to solve the problems of high-density interface states and surface dielectric defect states between dielectrics and group III nitrides and unstable threshold of enhanced devices.

[0005] One aspect of the present disclosure provides a composite dielectric structure of a gallium nitride electronic device, comprising: a low interface state dielectric insertion layer (1) and a high breakdown electric field dielectric layer (2); the low interface state dielectric insertion layer (1) is grown on the surface of the gallium nitride electronic device (3); and the high breakdown electric field dielectric layer (2) is grown on the low interface state dielectric insertion layer (1).

[0006] Optionally, the material of the low interface state dielectric insertion layer (1) includes any one of aluminum nitride, aluminum oxynitride, silicon nitride compounds, gallium oxide compounds or a combination thereof, and has a thickness of 0.2 nm to 5 nm.

[0007] Optionally, the material of the high breakdown electric field dielectric layer (2) includes any one of silicon nitride compounds, silicon dioxide, silicon oxynitride compounds, aluminum oxide, nickel oxide or a combination thereof, and has a thickness of 5 nm to 30 nm.

[0008] Another aspect of the present disclosure provides a method for preparing a composite dielectric structure of a gallium nitride electronic device, comprising: placing a gallium nitride electronic device (3) in a machine; adjusting the temperature of the machine to a first preset temperature, adjusting the power to a first preset power, and using plasma to clean the surface of the gallium nitride electronic device (3); adjusting the temperature of the machine to a second preset temperature, adjusting the power to a second preset power, and growing a low interface state dielectric insertion layer (1) on the surface of the gallium nitride electronic device (3); adjusting the temperature of the machine to a third preset temperature, adjusting the power to a third preset power, and growing a high breakdown electric field dielectric layer (2) on the low interface state dielectric insertion layer (1).

[0009] Optionally, the duration of using plasma to clean the surface of the gallium nitride electronic device (3) is 5 seconds to 20 minutes.

[0010] Optionally, when adjusting the temperature of the machine, the heating rate of the machine is 5 to 30 degrees Celsius per minute.

[0011] Optionally, after the temperature of the machine is adjusted to the first preset temperature, the second preset temperature and the third preset temperature respectively, the temperature stabilization time is 10 to 120 minutes.

[0012] Optionally, the first preset temperature is 25-250 degrees Celsius, the second preset temperature is 250-350 degrees Celsius, and the third preset temperature is 350-600 degrees Celsius.

[0013] Optionally, the first preset power is 50 to 500 watts, the second preset power is 500 to 2000 watts, and the third preset power is 2000 to 3000 watts.

[0014] Optionally, the gas precursor of the plasma is one or more of ammonia, nitrogen, and argon.

[0015] At least one of the above technical solutions adopted in the embodiments of the present disclosure can achieve the following beneficial effects:

[0016] A thin low interface state dielectric insertion layer and a thick high breakdown electric field dielectric layer are grown on the surface of the GaN electronic device to form a composite dielectric structure, which not only reduces the interface state density between the high breakdown dielectric and the III-nitride on the GaN electronic device, but also effectively prevents interface electrons from being injected into the high breakdown electric field dielectric. The composite dielectric structure can be used as a gate dielectric to regulate the threshold voltage of GaN-based enhanced MIS / MOS-HEMT, improve the stability and reliability of the threshold voltage, and can reduce interface leakage as a passivation dielectric.

[0017] By adjusting the machine temperature and power to regulate the plasma energy and wafer surface temperature of the surface treatment, the surface residue of the reactants can be effectively reduced, the surface roughness can be effectively reduced, the surface sacrificial layer can be removed and the surface can be smoothed, and the in-situ recovery of some surface damage can be achieved, laying the foundation for the growth of low-interface medium.

[0018] The process of heating up again and stabilizing the temperature before growing the high breakdown electric field dielectric layer can also anneal the low interface state dielectric insertion layer grown in the previous step, thereby improving the density and crystal quality of the insertion layer.

[0019] Carrying out surface treatment and in-situ growth in the same machine can eliminate contact with external environmental substances during process connection, effectively control unintentional contamination of each fresh surface (interface), avoid potential interface state problems caused by impurity elements such as carbon, oxygen, and hydrogen, and provide basic guarantee for the realization of low interface state insertion layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] For a more complete understanding of the present disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, in which:

[0021] Figure 1 A schematic structural diagram of a composite dielectric structure of a gallium nitride electronic device provided according to an embodiment of the present disclosure is shown;

[0022] Figure 2 A schematic diagram of the structure of a gallium nitride electronic device provided according to an embodiment of the present disclosure is shown;

[0023] Figure 3 A flow chart schematically shows a method for preparing a composite dielectric structure of a gallium nitride electronic device according to an embodiment of the present disclosure;

[0024] FIG4 schematically shows a schematic diagram of manufacturing a gate dielectric of a gallium nitride electronic device according to an embodiment of the present disclosure;

[0025] Figure 5 A schematic diagram showing the effect of changing the thickness of the low interface state dielectric insertion layer on the threshold voltage and CV curve of the gate dielectric according to an embodiment of the present disclosure is shown;

[0026] Figure 6 A CV curve diagram of a gate dielectric provided according to an embodiment of the present disclosure is schematically shown;

[0027] Figure 7 A current-voltage curve diagram of a composite passivation dielectric structure of a gallium nitride electronic device provided according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0029] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0030] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0031] Figure 1 A schematic structural diagram of a composite dielectric structure of a gallium nitride electronic device provided according to an embodiment of the present disclosure is schematically shown.

[0032] As shown in FIG1 , an embodiment of the present disclosure provides a composite dielectric structure of a gallium nitride electronic device, including: a low interface state dielectric insertion layer 1 and a high breakdown electric field dielectric layer 2 .

[0033] The low interface state dielectric insertion layer 1 is grown on the surface of the gallium nitride electronic device 3 .

[0034] The high breakdown electric field dielectric layer 2 is grown on the low interface state dielectric insertion layer 1 .

[0035] The material of the low interface state dielectric insertion layer 1 is aluminum nitride, aluminum oxynitride, silicon nitride compound, gallium oxide compound, and has a thickness of 0.2 nm to 5 nm.

[0036] The material of the high breakdown electric field dielectric layer 2 is silicon nitride compound, silicon dioxide, silicon oxynitride compound, aluminum oxide, and nickel oxide, and the thickness is 5 nm to 30 nm.

[0037] The present embodiment provides a composite dielectric structure of a gallium nitride electronic device, in which a thin low interface state dielectric insertion layer 1 and a thick high breakdown electric field dielectric layer 2 are grown on the surface of the gallium nitride electronic device, which not only reduces the interface state density between the high breakdown dielectric and the group III nitride on the gallium nitride electronic device, but also effectively prevents interface electrons from being injected into the high breakdown electric field dielectric layer 2, so that the composite dielectric structure can be used as a gate dielectric to regulate the threshold voltage of GaN-based enhanced MIS / MOS-HEMT, improve the stability and reliability of the threshold voltage, and can reduce interface leakage as a passivation medium.

[0038] Figure 2 The schematic diagram shows the structure of a gallium nitride electronic device 3 provided according to an embodiment of the present disclosure.

[0039] like Figure 2 As shown, the gallium nitride electronic device 3 includes a substrate 11, a group III nitride hierarchical structure, a source 9 and a drain 10. The group III nitride hierarchical structure includes, from bottom to top, a gallium nitride buffer layer 4, a gallium nitride channel layer 5, a two-dimensional electron gas layer 6, an aluminum nitride insertion layer 7 and a gallium aluminum nitride barrier layer 8. The source 9 and the drain 10 are arranged at both ends of the surface of the gallium aluminum nitride barrier layer 8.

[0040] refer to Figure 2 The low interface state dielectric insertion layer 1 is grown on the gallium nitride aluminum barrier layer 8 on the surface of the gallium nitride electronic device 3 .

[0041] Figure 3 A flow chart of a method for preparing a gallium nitride electronic device provided according to an embodiment of the present disclosure is schematically shown.

[0042] like Figure 3 As shown, the method for preparing the composite dielectric structure of the gallium nitride electronic device includes the following steps.

[0043] Step S1: placing the gallium nitride electronic device 3 in a machine platform.

[0044] Step S2: adjusting the temperature of the machine to a first preset temperature, adjusting the power to a first preset power, and using plasma to clean the surface of the gallium nitride electronic device 3 .

[0045] In this embodiment, the machine for processing the GaN electronic device may be one of PEALD (plasma-enhanced atomic-layer-deposition) and ICP-CVD.

[0046] The first preset temperature is 25 to 250 degrees Celsius, and the first preset power is 50 to 500 watts.

[0047] The gas precursor of the plasma may be one or more of ammonia, nitrogen, and argon.

[0048] In this embodiment, NH3 is used for deoxygenation and N2 is used for nitrogen supplementation. N is a component of the complete structure of the nitride surface. The presence of vacancies means incomplete surface structure and dangling bonds, which leads to a higher interface state. Ar is used to increase activity and remove residues. Generally, there is oxidation on the surface of nitride, and oxygen is a defect. Growing the medium directly on the gallium nitride electronic device will bring about an interface state. It is necessary to remove the surface oxide in advance to form a clean nitride interface.

[0049] The time for cleaning the surface of the gallium nitride electronic device 3 using plasma is 5 seconds to 20 minutes.

[0050] The gallium nitride electronic device 3 is cleaned under low temperature and low power conditions. By regulating the energy of the plasma and the surface temperature of the gallium nitride electronic device 3, the intrinsic oxide on the surface of the gallium nitride electronic device 3 can be removed, the surface roughness of the gallium nitride electronic device 3 can be effectively reduced, the surface of the gallium nitride electronic device 3 can be made flat, and in-situ recovery of partial surface damage of the gallium nitride electronic device 3 can be achieved, reducing damage to the surface of the gallium nitride electronic device 3, and laying a foundation for the growth of a medium with a low interface state.

[0051] Step S3: adjusting the temperature of the machine to a second preset temperature, adjusting the power to a second preset power, and growing a low interface state dielectric insertion layer 1 on the surface of the gallium nitride electronic device 3 .

[0052] The second preset temperature is 250 to 350 degrees Celsius, and the second preset power is 500 to 2000 watts.

[0053] The machine adjusts the temperature to a heating rate of 5 to 30 degrees Celsius per minute.

[0054] After the temperature of the machine is adjusted to the second preset temperature, the temperature stabilization time is 10 to 120 minutes.

[0055] The purpose of maintaining the temperature stable is to maintain the stability of subsequent growth. The low-interface-state dielectric insertion layer 1 is not grown during the temperature stable period, and the low-interface-state dielectric insertion layer 1 is grown again after the temperature stabilizes.

[0056] The material of the low interface state dielectric insertion layer 1 is any one of aluminum nitride, aluminum oxynitride, silicon nitride compound, gallium oxide compound or a combination thereof, and the thickness is 0.2 nm to 5 nm.

[0057] The function of the low interface state dielectric insertion layer 1 is to block the high breakdown electric field dielectric layer 2 grown later, so that the fresh surface of the gallium nitride electronic device 3 obtained after treatment can maintain the crystal structure at subsequent high temperatures, thereby reducing the secondary damage to the fresh surface of the previous gallium nitride electronic device 3.

[0058] Low interface state dielectrics can adjust the threshold voltage of GaN electronic devices and reduce interface leakage to a certain extent.

[0059] Step S4 : adjusting the temperature of the machine to a third preset temperature, adjusting the power to a third preset power, and growing a high breakdown electric field dielectric layer 2 on the low interface state dielectric insertion layer 1 .

[0060] The third preset temperature is 350-600 degrees Celsius, and the third preset power is 2000-3000 watts.

[0061] The machine adjusts the temperature to a heating rate of 5 to 30 degrees Celsius per minute.

[0062] After the temperature of the machine is adjusted to the third preset temperature, the temperature stabilization time is 10 to 120 minutes.

[0063] During the period of temperature stabilization, a high breakdown electric field dielectric layer 2 is grown on the low interface state dielectric insertion layer 1 of the gallium nitride electronic device.

[0064] The material of the high breakdown electric field dielectric layer 2 is any one of silicon nitride compounds, silicon dioxide, silicon oxynitride compounds, aluminum oxide, nickel oxide or a combination thereof, and has a thickness of 5 nm to 30 nm.

[0065] Growing the high breakdown electric field dielectric layer 2 under high temperature and high pressure can improve the density and crystal quality of the dielectric layer, and also anneal the low interface state dielectric insertion layer 1 grown in the previous step, thereby improving the density and crystal quality of the insertion layer.

[0066] The main function of the high breakdown electric field dielectric layer 2 is to increase the threshold voltage of the surface dielectric of the gallium nitride electronic device and reduce interface leakage.

[0067] In this embodiment, a thin low interface state dielectric insertion layer 1 is grown on the gallium nitride electronic device 3, and then a high breakdown electric field dielectric layer 2 is grown on the low interface state dielectric insertion layer 1. The low interface state dielectric insertion layer 1 reduces the interface state density between the high breakdown electric field dielectric layer 2 and the III-nitride in the gallium nitride electronic device, and can effectively prevent interface electrons from being injected into the high breakdown electric field dielectric. When the composite dielectric structure of the gallium nitride electronic device is used as a gate dielectric, the threshold voltage of the GaN-based enhanced MIS / MOS-HEMT can be regulated to improve the stability and reliability of the threshold voltage; when the composite dielectric structure of the gallium nitride electronic device is used as a passivation dielectric, the interface leakage can be reduced and the current collapse effect of the GaN-based microwave device can be suppressed.

[0068] FIG. 4 schematically shows a schematic diagram of manufacturing a gate dielectric according to an embodiment of the present disclosure.

[0069] according to Figure 3 A method for preparing a composite dielectric structure of a gallium nitride electronic device is provided, which can prepare a gate dielectric on the surface of the gallium nitride electronic device.

[0070] As shown in Figure 4, Figure (a) schematically shows the use of plasma to clean the surface of the gallium nitride electronic device 3, Figure (b) schematically shows the growth of a low interface state dielectric insertion layer 1 on the surface of the gallium nitride electronic device 3, Figure (c) schematically shows the growth of a high breakdown electric field dielectric layer 2 on the low interface state dielectric insertion layer 1, and Figure (d) schematically shows the deposition of a gate metal 12 on the high breakdown electric field dielectric layer 2.

[0071] In an embodiment of the present disclosure, a gate dielectric is prepared on a surface of a gallium nitride electronic device. The process of preparing the gate dielectric is as follows.

[0072] The gallium nitride electronic device 3 is placed in the machine.

[0073] The temperature and power of the machine are adjusted to the first preset temperature and the first preset power respectively, and the surface of the gallium nitride electronic device 3 is cleaned by plasma.

[0074] The temperature of the machine is adjusted to a second preset temperature, and the power is adjusted to a second preset power, and a low interface state dielectric insertion layer 1 is grown on the surface of the gallium nitride electronic device 3 .

[0075] The temperature of the machine is adjusted to a third preset temperature, the power is adjusted to a third preset power, and a high breakdown electric field dielectric layer 2 is grown on the low interface state dielectric insertion layer 1 .

[0076] A gate metal 12 is deposited on the high breakdown electric field dielectric layer 2 .

[0077] The gate dielectric prepared by the composite dielectric structure preparation method of a gallium nitride electronic device provided in an embodiment of the present disclosure can adjust the threshold voltage of a GaN-based enhanced MIS / MOS-HEMT and improve the stability and reliability of the threshold voltage.

[0078] Figure 5 The schematic diagram schematically shows the influence of changing the thickness of the low interface state dielectric insertion layer 1 on the threshold voltage and CV curve of the gate dielectric according to the embodiment of the present disclosure.

[0079] according to Figure 3 The gate dielectric is manufactured by the method shown. The composite dielectric structure formed by the low interface state dielectric insertion layer 1 and the high breakdown electric field dielectric layer 2 with different thicknesses will have different effects on the performance of the gate dielectric.

[0080] like Figure 5 As shown, the figure shows the influence of the composite gate dielectric structure composed of a 1-4nm thick AlN material low interface state dielectric insertion layer 1 and a 5nm thick SiN material high breakdown electric field dielectric layer 2 on the threshold voltage of GaN-based MIS-HEMT.

[0081] It can be seen from the figure that with the increase in the thickness of the low interface state dielectric insertion layer 1 of the AlN material, the threshold voltage of the GaN-based MIS-HEMT increases from a negative value to a positive value, achieving an enhanced mode.

[0082] It can also be seen from the figure that with the increase of the thickness of the AlN insertion layer, the hysteresis of the CV curve of the GaN-based MIS-HEMT decreases, achieving low interface states and low defects.

[0083] Figure 6 A CV curve diagram of a gate dielectric provided according to an embodiment of the present disclosure is schematically shown.

[0084] Figure 6 A CV curve diagram of a composite gate dielectric structure consisting of a 3 nm thick AlN material low interface state dielectric insertion layer 1 and a 5 nm thick SiN material high breakdown electric field dielectric layer 2 is schematically shown. The figure schematically shows the CV curves of a GaN-based MIS-HEMT using the composite gate dielectric structure when the test frequencies are 1K, 10K, 100K, and 1M, respectively.

[0085] It can be seen from the figure that the hysteresis of the CV curve is almost zero and the dispersion of the CV curve is very small.

[0086] Testing at different frequencies can distinguish the defect state density. Small hysteresis proves that there are fewer deep energy level defects, and small dispersion proves that there are fewer shallow energy level defects. Small dispersion of both proves that the composite gate dielectric structure has fewer defects as a whole.

[0087] Figure 7A current-voltage curve diagram of a composite passivation dielectric structure of a gallium nitride electronic device provided according to an embodiment of the present disclosure is schematically shown.

[0088] According to a method for preparing a gallium nitride electronic device provided by an embodiment of the present disclosure, a passivation composite medium can also be prepared on the surface of the gallium nitride electronic device.

[0089] like Figure 7 As shown, when a passivation composite is not prepared on the surface of a gallium nitride electronic device, as the voltage increases, the current passing through the gallium nitride electronic device will decrease, that is, the current collapses. According to a method for preparing a gallium nitride electronic device provided in an embodiment of the present disclosure, a passivation composite medium prepared on the surface of a gallium nitride electronic device can effectively suppress the current collapse effect of a GaN-based microwave device.

[0090] It will be appreciated by those skilled in the art that the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways without departing from the spirit and teachings of the present disclosure. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0091] Although the present disclosure has been shown and described with reference to specific exemplary embodiments of the present disclosure, it should be understood by those skilled in the art that various changes in form and details may be made to the present disclosure without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents. Therefore, the scope of the present disclosure should not be limited to the above-mentioned embodiments, but should be determined not only by the appended claims, but also by the equivalents of the appended claims.

Claims

1. A composite dielectric structure of a gallium nitride electronic device, characterized in that: include: A low interface state dielectric insertion layer (1) and a high breakdown electric field dielectric layer (2); A low interface state dielectric insertion layer (1) is grown on the surface of a gallium nitride electronic device (3); A high breakdown electric field dielectric layer (2) grown on the low interface state dielectric insertion layer (1); The material of the low interface state dielectric insertion layer (1) includes any one of aluminum nitride, aluminum oxynitride, silicon nitride compounds, gallium oxide compounds or a combination thereof, and has a thickness of 0.2 nm to 5 nm; The material of the high breakdown electric field dielectric layer (2) includes any one of silicon nitride compounds, silicon dioxide, silicon oxynitride compounds, aluminum oxide, nickel oxide or a combination thereof, and has a thickness of 5 nm to 30 nm; The low interface state dielectric insertion layer (1) is grown on the surface of the gallium nitride electronic device (3) under the conditions that the temperature of the machine is a second preset temperature and the power of the machine is a second preset power; Wherein, the high breakdown electric field dielectric layer (2) is grown on the low interface state dielectric insertion layer (1) under the condition that the temperature of the machine is a third preset temperature and the power of the machine is a third preset power; Among them, the second preset temperature is 250~350 degrees Celsius, the third preset temperature is 350~600 degrees Celsius, the second preset power is 500~2000 watts, and the third preset power is 2000~3000 watts.

2. A method for preparing a composite dielectric structure of a gallium nitride electronic device, characterized in that: include: Placing the gallium nitride electronic device (3) in a machine platform; The temperature of the machine is adjusted to a first preset temperature, the power is adjusted to a first preset power, and the surface of the gallium nitride electronic device (3) is cleaned using plasma; The temperature of the machine is adjusted to a second preset temperature, and the power is adjusted to a second preset power, and a low interface state dielectric insertion layer (1) is grown on the surface of the gallium nitride electronic device (3), wherein the material of the low interface state dielectric insertion layer (1) comprises any one of aluminum nitride, aluminum oxynitride, silicon nitride compound, gallium oxide compound or a combination thereof, and the thickness is 0.2 nm to 5 nm; The temperature of the machine is adjusted to a third preset temperature, and the power is adjusted to a third preset power, and a high breakdown electric field dielectric layer (2) is grown on the low interface state dielectric insertion layer (1), wherein the material of the high breakdown electric field dielectric layer (2) comprises any one of silicon nitride compounds, silicon dioxide, silicon oxynitride compounds, aluminum oxide, nickel oxide, or a combination thereof, and has a thickness of 5 nm to 30 nm; Among them, the second preset temperature is 250~350 degrees Celsius, the third preset temperature is 350~600 degrees Celsius, the second preset power is 500~2000 watts, and the third preset power is 2000~3000 watts.

3. The preparation method according to claim 2, characterized in that: The duration of using plasma to clean the surface of the gallium nitride electronic device (3) is 5 seconds to 20 minutes.

4. The preparation method according to claim 2, characterized in that: When adjusting the temperature of the machine, the heating rate of the machine is 5 to 30 degrees Celsius per minute.

5. The preparation method according to claim 2, characterized in that: After the temperature of the machine is adjusted to the first preset temperature, the second preset temperature and the third preset temperature respectively, the temperature stabilization time is 10 to 120 minutes.

6. The preparation method according to claim 2, characterized in that: The first preset temperature is 25-250 degrees Celsius.

7. The preparation method according to claim 2, characterized in that: The first preset power is 50~500 watts.

8. The preparation method according to claim 2, characterized in that: The gas precursor of the plasma is one or more of ammonia, nitrogen and argon.

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