GaN radio frequency electronics and methods of making the same

Abstract

The disclosure provides a GaN radio frequency electronic device and a manufacturing method thereof, and belongs to the technical field of semiconductors. The GaN radio frequency electronic device comprises a silicon substrate, a buffer layer, a GaN channel layer and an AlGaN barrier layer. The buffer layer comprises a first sub-layer and a second sub-layer which are stacked in sequence. The second sub-layer is connected with the GaN channel layer. The first sub-layer and the second sub-layer are both Fe-doped GaN layers. The Fe doping concentration of the first sub-layer is greater than that of the second sub-layer, and the Fe doping concentration of the second sub-layer is less than 1×10 17 cm ‑3 -2. The disclosure can improve the performance of the device.

Description

Technical Field

[0001] This disclosure belongs to the field of semiconductor technology, and specifically relates to a GaN radio frequency electronic device and its fabrication method. Background Technology

[0002] Due to the large size and low cost of silicon substrates, combined with the high-frequency characteristics of GaN materials, GaN radio frequency electronic devices on silicon substrates have become another focal area besides power devices.

[0003] In related technologies, the epitaxial structure of GaN radio frequency electronic devices on silicon substrates includes a silicon substrate and a GaN buffer layer, a GaN channel layer, and an AlGaN barrier layer sequentially stacked on the silicon substrate. Because the GaN buffer layer itself has a small number of freely moving background electrons (charge carriers), it is not absolutely insulating but exhibits n-type background conductivity. When a radio frequency signal is applied to the device, some electrons / current leak longitudinally from the GaN channel layer through the conductive GaN buffer layer to the silicon substrate and dissipates as heat. Some of the energy of the radio frequency signal is lost through leakage current, rather than being entirely used to amplify the output signal.

[0004] To improve the performance of GaN RF devices, a fixed concentration of Fe is doped into the GaN buffer layer. As a dominant impurity, Fe introduces deep energy levels into the GaN buffer layer, effectively trapping background electrons and compensating for the n-type conductivity background to form a high-resistivity state. This results in the Fe-doped GaN buffer layer exhibiting excellent high resistivity and good insulation, providing good longitudinal isolation for the two-dimensional electron gas generated between the GaN channel layer and the AlGaN barrier layer, effectively suppressing device leakage current and reducing RF losses.

[0005] However, Fe forms in the GaN buffer layer 3+ / 2+ While deep levels capture background electrons, they also act as deep level defects and recombination centers, significantly shortening the lifetime of high-speed electrons in the channel, which in turn leads to a decrease in device transconductance and a deterioration in frequency characteristics. Summary of the Invention

[0006] This disclosure provides a GaN radio frequency electronic device and its fabrication method, which can improve device performance. The technical solution is as follows: This disclosure provides a GaN radio frequency electronic device, comprising a silicon substrate, a buffer layer, a GaN channel layer, and an AlGaN barrier layer. The buffer layer comprises a first sublayer and a second sublayer stacked sequentially, the second sublayer being connected to the GaN channel layer. Both the first and second sublayers are Fe-doped GaN layers, with the Fe doping concentration of the first sublayer being greater than that of the second sublayer, and the Fe doping concentration of the second sublayer being less than 1 × 10⁻⁶. 17 cm -3 .

[0007] In another implementation of this disclosure, the first sublayer includes multiple Fe-doped sublayers with different Fe doping concentrations, wherein the Fe doping concentration in the multiple Fe-doped sublayers decreases monotonically along the direction from the first sublayer to the second sublayer.

[0008] In another implementation of this disclosure, the thickness of the plurality of Fe-doped sublayers decreases monotonically along the direction from the first sublayer to the second sublayer.

[0009] In another implementation of this disclosure, the total thickness of the first sublayer is 500nm~1250nm.

[0010] In another implementation of this disclosure, the Fe doping concentration of the first sublayer is 1×10⁻⁶. 17 cm -3 ~5×10 18 cm -3 .

[0011] In another implementation of this disclosure, the thickness of the second sublayer is 300 nm to 600 nm.

[0012] In another implementation of this disclosure, the buffer layer further includes a superlattice structure located between the silicon substrate and the first sublayer. The superlattice structure includes multiple unit structures, each unit structure including an AlGaN sublayer and a GaN sublayer. Along the direction from the first sublayer to the second sublayer, the Al composition in the AlGaN sublayer of the later unit structure is not greater than the Al composition in the AlGaN sublayer of the previous unit structure.

[0013] In another implementation of this disclosure, the plurality of unit structures include at least one first unit structure and at least one second unit structure, wherein the Al composition in the AlGaN sublayer of the first unit structure is higher than the Al composition in the AlGaN sublayer of the second unit structure, and the thickness of the first unit structure is less than the thickness of the second unit structure.

[0014] In another implementation of this disclosure, the thickness of the superlattice structure is 350 nm to 1200 nm.

[0015] On the other hand, this disclosure also provides a method for fabricating a GaN radio frequency electronic device, the method comprising: A buffer layer, a GaN channel layer, and an AlGaN barrier layer are sequentially stacked on a silicon substrate. The buffer layer comprises a first sub-layer and a second sub-layer stacked sequentially, the second sub-layer being connected to the GaN channel layer. Both the first and second sub-layers are Fe-doped GaN layers, with the Fe doping concentration of the first sub-layer being greater than that of the second sub-layer, and the Fe doping concentration of the second sub-layer being less than 1 × 10⁻⁶. 17 cm -3 .

[0016] The beneficial effects of the technical solutions provided in this disclosure are: Since the Fe doping concentration of the first sublayer is higher than that of the second sublayer, the high doping concentration in the first sublayer can provide high resistance characteristics for the buffer layer, suppressing leakage current. Meanwhile, the Fe doping concentration of the second sublayer is less than 1×10⁻⁶. 17 cm -3 This allows for interface optimization through low doping in the second sublayer, isolating the first sublayer from the GaN channel layer and preventing excessive Fe in the first sublayer. 3+ / 2+ The deep energy level (acting as an electron trap) is close to the channel layer, which can significantly reduce the rate at which high-speed electrons in the channel layer are trapped by Fe. 3+ / 2+ The probability of trapping and recombination in deep energy levels is increased, extending the lifetime of high-speed electrons and thus improving the problems of transconductance reduction and frequency characteristic deterioration caused by deep energy level effects. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a GaN radio frequency electronic device provided in an embodiment of this disclosure; Figure 2 This is a schematic diagram of another GaN radio frequency electronic device provided in this embodiment of the disclosure; Figure 3 This is a flowchart illustrating a method for fabricating a GaN radio frequency electronic device according to an embodiment of this disclosure; Figure 4 This is a flowchart of another method for fabricating a GaN radio frequency electronic device provided in this disclosure.

[0019] The symbols in the diagram represent the following meanings: 1. Silicon substrate; 2. Buffer layer; 21. First sublayer; 211. High Fe doped sublayer; 212. Medium Fe doped sublayer; 213. Low Fe doped sublayer; 22. Second sublayer; 23. Superlattice structure; 3. GaN channel layer; 4. AlGaN barrier layer; 5. Nucleation layer; 6. GaN cap layer. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0021] This disclosure provides a GaN radio frequency electronic device, such as... Figure 1 As shown, the GaN radio frequency electronic device includes a silicon substrate 1 and a buffer layer 2, a GaN channel layer 3 and an AlGaN barrier layer 4 sequentially stacked on the silicon substrate 1.

[0022] The buffer layer 2 comprises a first sublayer 21 and a second sublayer 22 stacked sequentially. The second sublayer 22 is connected to the GaN channel layer 3. Both the first sublayer 21 and the second sublayer 22 are Fe-doped GaN layers. The Fe doping concentration of the first sublayer 21 is greater than that of the second sublayer 22, and the Fe doping concentration of the second sublayer 22 is less than 1 × 10⁻⁶. 17 cm -3 .

[0023] In the GaN radio frequency electronic device provided in this embodiment, since the Fe doping concentration of the first sublayer 21 is greater than that of the second sublayer 22, the high doping concentration in the first sublayer 21 can provide high impedance characteristics for the buffer layer 2, suppressing leakage current. Meanwhile, the Fe doping concentration of the second sublayer 22 is less than 1×10⁻⁶. 17 cm -3 This allows for interface optimization through low doping in the second sub-layer 22, isolating the first sub-layer 21 from the GaN channel layer 3 and preventing excessive Fe in the first sub-layer 21. 3+ / 2+ The deep energy level (acting as an electron trap) is close to GaN channel layer 3, which can significantly reduce the high-speed electrons trapped in GaN channel layer 3 by Fe. 3+ / 2+ The probability of trapping and recombination in deep energy levels is increased, extending the lifetime of high-speed electrons and thus improving the problems of transconductance reduction and frequency characteristic deterioration caused by deep energy level effects.

[0024] Optionally, the first sublayer 21 includes multiple Fe-doped sublayers with different Fe doping concentrations, and the Fe doping concentration in the multiple Fe-doped sublayers decreases monotonically along the direction from the first sublayer 21 to the second sublayer 22.

[0025] In the above implementation, using a higher Fe doping concentration near the silicon substrate 1 in the buffer layer 2 allows this region to exhibit the strongest insulation capability, thus blocking leakage current from the silicon substrate 1. Even though a higher Fe doping concentration may induce more Fe... 3+ / 2+ The deep-level traps are largely unaffected because this region is far from the GaN channel layer 3, and the two-dimensional electron gas generated by the GaN channel layer 3 and AlGaN barrier layer 4 is far away. Fe here allows the bottom of the buffer layer 2 to act as an insulator. However, a lower Fe doping concentration is used near the second sublayer 22, that is, near the top of the buffer layer 2 and the channel, because this area is very close to the two-dimensional electron gas channel. Lowering the Fe doping concentration means that the deep-level trap density in this region is extremely low. Thus, high-speed electrons in the channel are almost unaffected by Fe during their movement. 3+ / 2+ Deep-level trapping or scattering. Therefore, setting the first sublayer 21 as multiple Fe-doped sublayers with different Fe doping concentrations can effectively alleviate Fe trapping. 3+ / 2+ Problems that impair high-frequency characteristics.

[0026] Optionally, the thickness of the multiple Fe-doped sublayers decreases monotonically along the direction from the first sublayer 21 to the second sublayer 22.

[0027] In the above implementation, a high Fe doping concentration and a relatively large thickness are used near the bottom of the silicon substrate 1. This ensures that the area most requiring insulation has sufficient thickness to block leakage paths from the silicon substrate. Conversely, an extremely low Fe doping concentration and an extremely thin thickness are used near the two-dimensional electron gas channel. This allows the low-doping characteristics to effectively isolate the underlying high-trap region. This can be achieved by reducing the thickness to decrease the amount of Fe present in this region. 3+ / 2+ The total number of deep-level traps is reduced, thereby decreasing the impact on channel electrons.

[0028] Optionally, the Fe doping concentration of the first sublayer 21 is 1×10⁻⁶. 17 cm -3 ~5×10 18 cm -3 .

[0029] In the above implementation, the above settings allow the Fe doping concentration of the first sublayer 21 to have a large range, so that it can achieve high resistance characteristics while also being compatible with the second sublayer 22.

[0030] Figure 2 This is a schematic diagram of another GaN radio frequency electronic device provided in this disclosure embodiment, see below. Figure 2 In this embodiment, the first sub-layer 21 may include a high-Fe doped sub-layer 211, a medium-Fe doped sub-layer 212, and a low-Fe doped sub-layer 213 stacked sequentially.

[0031] Among them, the Fe doping concentration of the high Fe-doped sublayer 211 is greater than 5 × 10⁻⁶. 18 cm -3 This provides high resistance characteristics and suppresses leakage current.

[0032] The Fe doping concentration of the Fe-doped sublayer 212 is 5 × 10⁻⁶. 17 cm -3 ~5×10 18 cm -3 The medium-Fe doped sublayer 212 serves as a transition region, balancing stress and resistance. The low-Fe doped sublayer 213 has an Fe doping concentration of 1 × 10⁻⁶. 17 cm -3 ~5×10 17 cm -3 The low-Fe-doped sublayer 213 is a defect-controlling region, which can reduce scattering centers.

[0033] For example, the Fe doping concentration of the highly Fe-doped sublayer 211 is 8 × 10⁻⁶. 18 cm -3 The Fe doping concentration of the Fe-doped sublayer 212 is 8 × 10⁻⁶. 17 cm -3 The Fe doping concentration of the low-Fe-doped sublayer 213 is 3 × 10⁻⁶. 17 cm -3 .

[0034] In other examples, the first sublayer 21 may also include more Fe-doped sublayers, such as four or five. The specific configuration depends on the process conditions and actual requirements.

[0035] Optionally, the total thickness of the first sublayer 21 is 500nm~1250nm.

[0036] In the above implementation, the longitudinal breakdown voltage of a semiconductor device is directly related to the thickness of the high-resistivity layer. Generally, the greater the thickness, the higher the voltage it can withstand. The above thickness setting allows the first sublayer 21 to have a higher breakdown voltage, improving the reliability of the device; it also provides ample space for gradient doping of the first sublayer 21.

[0037] Optionally, the thickness of the second sublayer 22 is 300nm~600nm.

[0038] In the above implementation, since the second sublayer 22 serves as the interface layer adjacent to the active channel, its primary task is to minimize the impact of Fe deep-level traps on high-speed electrons, ensuring high transconductance and excellent frequency characteristics. If the thickness of the second sublayer 22 is too thin (<300nm), it may not be able to effectively shield or isolate the high-density Fe traps in the underlying highly Fe-doped sublayer 211. The high-density Fe traps below may still affect channel electrons through tunneling or long-range Coulomb scattering, leading to increased current collapse and decreased electron mobility. If it is too thick (>600nm), although the isolation effect is better, the total absolute number of Fe atoms inside will also increase linearly with the thickness. More Fe atoms mean more deep levels, which will directly lead to an increase in parasitic capacitance and a higher carrier recombination probability, thus dragging down the high-frequency response speed and power efficiency. Therefore, the above thickness not only provides sufficient isolation but also controls the total number of traps to prevent it from becoming too large.

[0039] For example, the thickness of the second sublayer 22 is 450 nm.

[0040] Optionally, the buffer layer 2 also includes a superlattice structure 23 located between the silicon substrate 1 and the first sublayer 21.

[0041] Each superlattice structure 23 comprises multiple sequentially stacked unit structures. Each unit structure includes an AlGaN sublayer and a GaN sublayer. Along the direction from the first sublayer 21 to the second sublayer 22, the Al composition in the AlGaN sublayer of the later unit structure is no greater than the Al composition in the AlGaN sublayer of the previous unit structure.

[0042] The statement above, that the Al composition in the AlGaN sublayer of a later unit cell structure is not greater than the Al composition in the AlGaN sublayer of a previous unit cell structure, means that the Al composition in the AlGaN sublayer of a later unit cell structure is equal to or less than the Al composition in the AlGaN sublayer of a previous unit cell structure. That is, all unit cell structures have the same Al composition. Alternatively, at least one unit cell structure has an Al composition less than the Al composition in the AlGaN sublayer of a previous superlattice structure. Or, the Al composition in the unit cell structures exhibits a monotonically decreasing trend.

[0043] In the above implementation, at the AlGaN / GaN interface in each unit structure, an elastic strain field is generated due to the slight difference in lattice constant. When penetrating dislocations extending upward from the silicon substrate 1 encounter these interfaces, their extension direction is repeatedly bent, deflected, and even merged. This confines most harmful dislocations within the superlattice structure 23, preventing them from propagating upward into the GaN channel layer 3. This significantly reduces the dislocation density in the GaN channel layer 3, thereby reducing scattering and leakage caused by crystal defects at the source and laying the material foundation for low RF loss.

[0044] By limiting the Al composition in the AlGaN sublayer of the subsequent unit structure to no greater than the Al composition in the AlGaN sublayer of the previous unit structure, the Al composition in the superlattice structure 23 can be kept constant / decreasing, so as to strongly capture and terminate the initial high-density dislocations from the silicon substrate 1.

[0045] As the Al composition of the AlGaN layers in the subsequent unit structure gradually decreases (i.e., the lattice constant gradually increases, moving closer to GaN), a continuous transition region from Al-rich to Ga-rich is essentially constructed at the nanoscale. Compared with the constant Al composition superlattice structure 23, this design has a softer and more continuous relaxation stress, avoiding excessive stress abrupt changes at a single interface, thereby further reducing the risk of new defects at the interface.

[0046] The specific Al composition in each superlattice structure can be set depending on the specific device performance targets and the process capabilities of the epitaxial fabrication plant.

[0047] Optionally, the multiple unit structures include at least one first unit structure and at least one second unit structure, wherein the Al composition in the AlGaN sublayer of the first unit structure is higher than the Al composition in the AlGaN sublayer of the second unit structure, and the thickness of the first unit structure is less than the thickness of the second unit structure.

[0048] In the above implementation, the above settings mean that in the unit structure with high Al content, the corresponding unit structure is thinner.

[0049] The higher the Al content in an AlGaN layer, the greater the lattice mismatch relative to GaN, and the stronger the introduced tensile stress. If the high-stress material layer is too thick, it is highly susceptible to instability, leading to defects or even cracking. Therefore, as the Al content decreases, the lattice mismatch and stress weaken, and the material stability increases. In this case, increasing the thickness of each unit structure does not cause instability; instead, it improves epitaxial growth efficiency and makes the overall structure more stable as a bulk GaN material. However, if all unit structures have the same thickness, the drastic change in stress state during the transition from high to low Al content can easily lead to surface ripples or roughness. A thin-to-thick transition design results in a gentler stress gradient, which is beneficial for growing atomically smooth surfaces.

[0050] Optionally, the number of unit structures with the same Al composition is 3 to 15.

[0051] In the above implementation, the above settings allow each segment of the superlattice structure 2 to have a periodic group (3-15 periods) with a fixed Al composition, thus corresponding to a stress plateau. This segmented constant design is more stable and repeatable in terms of process, while also enabling gradual stress release, making it easier for process engineers to implement.

[0052] For example, the superlattice structure 23 can be divided into several segments: the first segment (5 periods, Al composition = 30%), the second segment (5 periods, Al composition = 20%), and the third segment (5 periods, Al composition = 10%).

[0053] Optionally, the thickness of the superlattice structure 23 is 350 nm to 1200 nm.

[0054] In the above implementation, the above settings can ensure that the superlattice structure 23 has sufficient thickness to annihilate defects, so that defects cannot propagate upward.

[0055] Optionally, the GaN radio frequency electronic device further includes a nucleation layer 5, which is located between the buffer layer 2 and the silicon substrate 1. The nucleation layer 5 is an AlN layer with a thickness of 15 nm to 50 nm.

[0056] In the above implementation, the nucleation layer 5 is the starting layer for epitaxial growth. Its core function is to provide nucleation sites on the silicon substrate 1 that are compatible with the GaN lattice, effectively alleviate the lattice mismatch between the silicon substrate 1 and the buffer layer 2, suppress the adverse reaction between silicon and nitrides, and reduce the density of through dislocations, thereby laying the foundation for the subsequent formation of a high-quality GaN channel layer 3.

[0057] Optionally, the layer in contact with the nucleation layer 5 in the superlattice structure 23 is an AlGaN layer. The role of the nucleation layer (AlN) is to provide a starting surface that is more compatible with the lattice constant of GaN (compared to silicon) and to suppress the reaction between Si and Ga. To ensure a smooth transition from the AlN layer to the GaN layer, the first layer of the superlattice structure 23 is made of an Al-rich material (i.e., an AlGaN sublayer). This ensures that the change in lattice constant from the nucleation layer to the superlattice is gradual, avoiding the generation of a large number of new defects due to abrupt lattice changes.

[0058] Optionally, the GaN RF electronic device also includes a GaN cap layer 6. The GaN cap layer 6 is located on and connected to the AlGaN barrier layer 4.

[0059] In the above implementation, the GaN cap layer 6 is used to cover and protect the atmosphere-sensitive AlGaN surface, significantly reducing the surface state density, thereby effectively suppressing the current collapse effect caused by surface state charge fluctuations and improving the stability of the device's dynamic performance.

[0060] For example, the thickness of the GaN cap layer 6 is 1nm to 5nm.

[0061] Without significantly altering the heterojunction band structure formed by the GaN channel layer and AlGaN barrier layer, surface passivation and ohmic contact optimization are achieved with minimal thickness. This size design ensures that the device simultaneously achieves key improvements in both high-frequency dynamic performance and DC output capability.

[0062] This disclosure also provides a method for fabricating a GaN radio frequency electronic device, such as... Figure 3 As shown, the manufacturing method includes: S301: A buffer layer, a GaN channel layer, and an AlGaN barrier layer are formed sequentially on a silicon substrate.

[0063] The buffer layer comprises a first sublayer and a second sublayer stacked sequentially. The second sublayer is connected to the GaN channel layer. Both the first and second sublayers are Fe-doped GaN layers. The Fe doping concentration of the first sublayer is greater than that of the second sublayer, and the Fe doping concentration of the second sublayer is less than 1 × 10⁻⁶. 17 cm -3 .

[0064] The above manufacturing methods have the same beneficial effects as the aforementioned GaN RF electronic devices, and will not be repeated here.

[0065] This disclosure also provides another method for fabricating GaN radio frequency electronic devices, wherein GaN radio frequency electronic devices are epitaxially formed using a metal-organic chemical vapor deposition (MOCVD) apparatus. For example... Figure 4 As shown, the manufacturing method includes: S401: An AlN nucleation layer is epitaxially formed on a silicon substrate.

[0066] The temperature of the reaction chamber of the epitaxial device is controlled at 400℃~550℃, and the reaction time is controlled to form an AlN nucleation layer with a thickness of 15nm~50nm.

[0067] S402: A buffer layer is formed epitaxially on the nucleation layer.

[0068] Optionally, S402 includes the following steps: 4021: A superlattice structure is epitaxially formed on the nucleation layer.

[0069] The superlattice structure is the same as the superlattice described above, and will not be repeated here.

[0070] The temperature of the reaction chamber was controlled at 950℃~1150℃, and the reaction time was controlled to form a superlattice structure with a thickness of 350nm~1200nm.

[0071] 4022: The first sublayer is formed epitaxially on a superlattice structure.

[0072] The temperature of the reaction chamber is maintained at 950℃~1150℃, and the reaction time is controlled to form a first sublayer with a thickness of 500nm~1250nm.

[0073] The first sub-layer is the structure described above, and will not be repeated here.

[0074] 4023: The second sublayer is formed by extension on the first sublayer.

[0075] The temperature of the reaction chamber is maintained at 950℃~1150℃, and the reaction time is controlled to form a second sublayer with a thickness of 300nm~600nm.

[0076] S403: GaN channel layer is epitaxially formed on the buffer layer.

[0077] The temperature of the reaction chamber is controlled at 1000℃~1150℃, and the reaction time is controlled to form a GaN channel layer with a thickness of 150nm~300nm.

[0078] S404: An AlGaN barrier layer is epitaxially formed on the GaN channel layer.

[0079] The temperature of the reaction chamber is controlled at 1000℃~1150℃, and the reaction time is controlled to form an AlGaN barrier layer with a thickness of 15nm~26nm.

[0080] S405: A GaN cap layer is epitaxially formed on the AlGaN barrier layer.

[0081] Continue in situ growth of GaN cap layer and control the reaction time to form GaN cap layer with a thickness of 1nm~5nm.

[0082] In this embodiment, to address the deep-level defect problem caused by Fe doping, the negative impact is significantly reduced while retaining the benefits of high resistivity brought by Fe doping through material structure innovation and process optimization.

[0083] The performance parameters of the GaN RF electronic device provided in this embodiment are compared with those of GaN RF electronic devices in related technologies, as shown in the table below: The GaN radio frequency electronic device provided in this embodiment differs from GaN radio frequency electronic devices in related technologies only in the doping method of the buffer layer; the other structures are completely identical.

[0084] Table 1

[0085] The Fe doping uniformity in Table 1 was determined using secondary ion mass spectrometry. High-energy ion beams were used to bombard the sample surface, sputtering ions of elements such as Fe. The mass and quantity of these ions were analyzed using mass spectrometry to obtain the Fe element concentration distribution curve from surface to depth. This Fe element concentration distribution curve reflects the Fe doping uniformity. The interface state density in Table 1 was obtained using the pulsed IV method. Channel mobility was obtained using the device transconductance extraction method. On-resistance was measured using the DC linear region IV method. Saturation current density was measured using DC output characteristics.

[0086] According to Table 1 above, the GaN RF electronic device provided in this embodiment has improved performance compared to GaN RF electronic devices in related technologies.

[0087] Achieving both a longitudinal gradient distribution and a lateral uniform distribution of Fe doping concentration within the GaN buffer layer, with a higher Fe doping concentration near the silicon substrate to effectively suppress leakage current, and a significantly reduced Fe doping concentration near the channel layer to effectively reduce Coulomb scattering centers. Furthermore, the combination of an AlGaN / GaN superlattice structure with Fe doping effectively addresses stress control and defect suppression issues. By precisely controlling the Fe doping concentration and distribution, active regulation of carrier recombination is achieved, effectively balancing resistivity and carrier mobility.

[0088] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” “third,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” “right,” etc., are used only to indicate relative positional relationships; when the absolute position of the described objects changes, the relative positional relationship may also change accordingly.

[0089] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A GaN radio frequency electronic device, characterized in that, The GaN radio frequency electronic device includes a silicon substrate (1), a buffer layer (2), a GaN channel layer (3), and an AlGaN barrier layer (4). The buffer layer (2) comprises a first sublayer (21) and a second sublayer (22) stacked sequentially. The second sublayer (22) is connected to the GaN channel layer (3). Both the first sublayer (21) and the second sublayer (22) are Fe-doped GaN layers. The Fe doping concentration of the first sublayer (21) is greater than that of the second sublayer (22), and the Fe doping concentration of the second sublayer (22) is less than 1×10⁻⁶. 17 cm -3 .

2. The GaN radio frequency electronic device according to claim 1, characterized in that, The first sublayer (21) includes multiple Fe-doped sublayers with different Fe doping concentrations, and the Fe doping concentration in the multiple Fe-doped sublayers decreases monotonically along the direction from the first sublayer (21) to the second sublayer (22).

3. The GaN radio frequency electronic device according to claim 2, characterized in that, The thickness of the plurality of Fe-doped sublayers decreases monotonically along the direction from the first sublayer (21) to the second sublayer (22).

4. The GaN radio frequency electronic device according to any one of claims 1-3, characterized in that, The total thickness of the first sublayer (21) is 500nm~1250nm.

5. The GaN radio frequency electronic device according to any one of claims 1-3, characterized in that, The Fe doping concentration of the first sublayer (21) is 1×10 17 cm -3 ~5×10 18 cm -3 .

6. The GaN radio frequency electronic device according to any one of claims 1-3, characterized in that, The thickness of the second sublayer (22) is 300nm~600nm.

7. The GaN radio frequency electronic device according to any one of claims 1-3, characterized in that, The buffer layer (2) further includes a superlattice structure (23) located between the silicon substrate (1) and the first sublayer (21), the superlattice structure (23) including multiple unit structures, each unit structure including an AlGaN sublayer and a GaN sublayer; Along the direction from the first sublayer (21) to the second sublayer (22), the Al composition in the AlGaN sublayer of the latter unit structure is not greater than the Al composition in the AlGaN sublayer of the former unit structure.

8. The GaN radio frequency electronic device according to claim 7, characterized in that, The plurality of unit structures include at least one first unit structure and at least one second unit structure, wherein the Al content in the AlGaN sublayer of the first unit structure is higher than the Al content in the AlGaN sublayer of the second unit structure, and the thickness of the first unit structure is less than the thickness of the second unit structure.

9. The GaN radio frequency electronic device according to claim 7, characterized in that, The thickness of the superlattice structure (23) is 350 nm to 1200 nm.

10. A method for fabricating a GaN radio frequency electronic device, characterized in that, The manufacturing method includes: A buffer layer, a GaN channel layer, and an AlGaN barrier layer are sequentially stacked on a silicon substrate. The buffer layer comprises a first sub-layer and a second sub-layer stacked sequentially. The second sub-layer is connected to the GaN channel layer. Both the first and second sub-layers are Fe-doped GaN layers. The Fe doping concentration of the first sub-layer is greater than that of the second sub-layer, and the Fe doping concentration of the second sub-layer is less than 1 × 10⁻⁶. 17 cm -3 .

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