A semiconductor device and a manufacturing method thereof

Abstract

Embodiments of the present application disclose a semiconductor device and a manufacturing method thereof. The semiconductor device can include a substrate, an epitaxial layer and an electrode on the substrate, wherein the substrate has a diamond structure longitudinally penetrating through the substrate, the diamond structure can be divided into a first diamond part and a second diamond part below the first diamond part in the longitudinal direction, and the first diamond part and the second diamond part have different lateral dimensions. Since the diamond structure has good heat conduction performance, the diamond structure penetrating through the substrate can form a longitudinal heat conduction channel, thereby improving the heat dissipation performance of the semiconductor device and facilitating the effective exertion of high-power performance of the semiconductor device. In addition, the first diamond part and the second diamond part have different lateral dimensions, which facilitates the control of the structures of the first diamond part and the second diamond part, and meanwhile, the heat dissipation performance and the lattice matching between the epitaxial layer can be considered, thereby obtaining a higher-quality epitaxial layer and a high-performance semiconductor device.

Description

Technical Field

[0001] This application relates to the field of semiconductor manufacturing technology, and in particular to a semiconductor device and a method for manufacturing the same. Background Technology

[0002] In semiconductor devices, the heat dissipation performance of the substrate is an important factor affecting device performance. In some scenarios, the high power performance of semiconductor devices cannot be effectively utilized due to the limitations of substrate heat dissipation.

[0003] For example, with the development trend of high frequency and high power, high-electron-mobility transistors (HEMTs) based on gallium nitride (GaN) are increasingly used in power amplifier (PA) chips in the 5G field. As a third-generation wide-bandgap semiconductor material, gallium nitride has advantages such as high two-dimensional electron gas concentration and breakdown voltage, as well as high electron saturation velocity. These advantages provide favorable conditions for nitride device structures to function as high-power devices. These new application scenarios also place higher demands on the power, frequency, efficiency, and reliability of gallium nitride-based HEMT devices. However, heat dissipation has become a key bottleneck for gallium nitride-based HEMT devices. This is because the substrates currently used are mostly silicon-based and sapphire-based materials, which have poor thermal conductivity. When gallium nitride devices output power, they generate a large amount of heat. The low thermal conductivity of the substrate material cannot dissipate this large amount of heat in time, limiting the performance of gallium nitride functional devices. Summary of the Invention

[0004] In view of this, the first aspect of this application provides a semiconductor device and a method for manufacturing the same, which improves the heat dissipation performance of the semiconductor device and facilitates the effective utilization of the high power performance of the semiconductor device.

[0005] A first aspect of this application provides a semiconductor device, including a substrate, an epitaxial layer, and electrodes sequentially disposed on the substrate. The substrate has a diamond structure extending longitudinally through the substrate. The diamond structure is divided into a first diamond portion and a second diamond portion in the longitudinal direction. The second diamond portion may be located below the first diamond portion. The lateral dimensions of the first and second diamond portions may be different; specifically, they may be completely different or not completely identical. Due to the good thermal conductivity of the diamond structure, the diamond structure extending through the substrate can form a longitudinal heat conduction channel, thereby efficiently conducting the heat generated during device operation to the device periphery, improving the heat dissipation performance of the semiconductor device, and facilitating the effective utilization of the high-power performance of the semiconductor device. Furthermore, the different lateral dimensions of the first and second diamond portions can be achieved through a two-stage etching process, reducing the etching aspect ratio, which facilitates control over the structure of the first and second diamond portions. Simultaneously, it can balance heat dissipation performance and lattice matching between epitaxial layers, resulting in a higher quality epitaxial layer and a high-performance semiconductor device.

[0006] In some possible implementations, there are multiple first diamond structures and multiple second diamond structures, with each of the multiple first diamond portions and multiple second diamond portions corresponding one-to-one, and each being at least one of a frustum structure, a truncated pyramid structure, a bowl-shaped structure, a cylindrical structure, and a prism structure.

[0007] In this embodiment, the first diamond portion and the second diamond portion can correspond one-to-one. Thus, a first diamond structure and a second diamond structure can form a vertical heat-conducting channel, allowing heat to be dissipated to the device periphery through multiple channels, achieving high heat dissipation efficiency. The first diamond portion and the second diamond portion can have various shapes, allowing for targeted design for different epitaxial layers, thereby balancing heat dissipation performance and lattice matching, and improving epitaxial quality.

[0008] In some possible implementations, the number of second diamond portions is less than the number of first diamond portions, and there are multiple first diamond portions connected to the same second diamond portion, wherein the first diamond portion is at least one of a frustum structure, a prismatic structure, a bowl-shaped structure, a cylindrical structure, and a prismatic structure.

[0009] In this embodiment, the number of second diamond portions below can be less than the number of first diamond portions, so that one second diamond portion can be connected to multiple first diamond portions. Thus, the lateral dimension of the second diamond portion can be larger than that of the first diamond portion, so that more diamond is exposed on the surface of the substrate away from the epitaxial layer, while less diamond is exposed on the surface of the epitaxial layer, ensuring the heat dissipation performance of the device while taking into account the epitaxial quality.

[0010] In some possible implementations, the second diamond portion is a single entity and is longitudinally connected to all or part of the first diamond portion.

[0011] In this embodiment, there is one second diamond portion, which allows the second diamond portion to have a larger lateral dimension, thereby further improving the heat dissipation performance of the device without affecting the quality of the epitaxial layer.

[0012] In some possible implementations, there are multiple second diamond portions that extend in a predetermined direction parallel to the surface of the substrate, and at least one second diamond portion is longitudinally connected to multiple first diamond portions.

[0013] In this embodiment, there may be multiple second diamond portions, which may extend in the same direction. This allows the second diamond portions to have a larger lateral dimension, thereby further improving the heat dissipation performance of the device without affecting the quality of the epitaxial layer.

[0014] In some possible implementations, the lateral dimension of the first diamond portion ranges from 1 to 10 μm, the longitudinal dimension of the first diamond portion ranges from 1 to 10 μm, the spacing between different first diamond portions ranges from 1 to 10 μm, and the thickness of the substrate ranges from 50 to 100 μm.

[0015] In this embodiment, the first diamond portion may occupy a small portion of the substrate thickness, and there is a reasonable spacing between each first diamond portion, thereby ensuring the heat dissipation performance of the device while ensuring the quality of the epitaxial layer.

[0016] In some possible implementations, the substrate is made of one or more of silicon, silicon carbide, aluminum nitride, and sapphire.

[0017] In this embodiment, the substrate can be one or more of silicon substrate, silicon carbide substrate, aluminum nitride substrate, and sapphire substrate. Even if the heat dissipation performance of the substrate is not good enough, the heat dissipation performance of the device can be guaranteed after forming a heat dissipation channel with diamond. Moreover, the manufacturing process of these substrates is simple and easy to mass-produce.

[0018] In some possible implementations, the diamond structure is single-crystal diamond or polycrystalline diamond.

[0019] In this embodiment, the diamond structure can be either single-crystal diamond or polycrystalline diamond, which can be determined according to the actual situation, as long as it can achieve good heat dissipation.

[0020] In some possible implementations, the epitaxial layer includes a buffer layer and a barrier layer, wherein the buffer layer is a gallium nitride layer and the barrier layer is made of one or more of AlGaN, InAlN, AlN, and ScAlN.

[0021] In this embodiment, the epitaxial layer may include a buffer layer and a barrier layer. The buffer layer may be a gallium nitride layer, and the semiconductor structure may be a gallium nitride device. A two-dimensional electron gas may be formed between the barrier layer and the gallium nitride layer, thereby providing better device performance.

[0022] In some possible implementations, the thickness of the gallium nitride layer ranges from 0.1 to 2 μm, and the thickness of the barrier layer ranges from 5 to 20 nm.

[0023] In this embodiment, the thickness of the gallium nitride layer and the barrier layer can be within a reasonable range to ensure the performance of the device.

[0024] In some possible implementations, the electrode includes a source, a drain, and a gate, and the material of the electrode is at least one selected from Au, Ti, Al, Ni, and Ta.

[0025] In this embodiment, the electrode may include a source, a drain, and a gate, and the electrode material can be of various types, ensuring the integrity and superior performance of the device.

[0026] A second aspect of this application provides a method for forming a semiconductor device, comprising:

[0027] Provide substrate;

[0028] The first trench is obtained by etching the first surface of the substrate;

[0029] The first trench is filled with diamond material;

[0030] An epitaxial layer and an electrode are sequentially formed on the first surface of the substrate;

[0031] The second surface of the substrate is etched to form a second trench, which is connected to the first trench and has different lateral dimensions; the first surface and the second surface are two opposing surfaces.

[0032] The second groove is filled with diamond material.

[0033] In this embodiment, diamond material on the first surface of the substrate can be formed first, then the device structure on the substrate can be formed, and then the diamond structure on the second surface can be formed. This matches the steps of forming the device structure and then flipping the device for bonding in the prior art. Therefore, the high-performance and high-heat-dissipation device in this embodiment can be obtained with as few steps as possible.

[0034] In some possible implementations, there are multiple first grooves and multiple second grooves, with each of the multiple first grooves and multiple second grooves corresponding one-to-one, and the diamond material in the first grooves and the second grooves has at least one of the following shapes: frustum structure, prismatic structure, bowl-shaped structure, cylindrical structure, and prismatic structure.

[0035] In some possible implementations, the number of second grooves is less than the number of first grooves, and there are multiple first grooves connected to the same second groove. The shape of the first groove is one of the following: frustum structure, prismatic structure, bowl-shaped structure, cylindrical structure, and prismatic structure.

[0036] In some possible implementations, the second trench is a single trench, and the bottom of the second trench exposes all or part of the diamond material in the first trench.

[0037] In some possible implementations, the second trench is a plurality of trenches extending in a predetermined direction parallel to the surface of the substrate, and at least one of the second trenches has the bottom exposed diamond material in the plurality of first trenches.

[0038] In some possible implementations, before etching the second surface of the substrate to form the second trench, the method further includes:

[0039] The substrate is thinned from its second surface.

[0040] A third aspect of this application provides a method for forming a semiconductor device, comprising:

[0041] Provide substrate;

[0042] A first trench is formed by etching from a first surface of the substrate and filled with diamond material; and a second trench is formed by etching from a second surface of the substrate and filled with diamond material; the first trench and the second trench are connected and have different lateral dimensions; the first surface and the second surface are two opposing surfaces;

[0043] An epitaxial layer and an electrode are sequentially formed on the first surface of the substrate.

[0044] In this embodiment, diamond material on the first surface of the substrate can be formed first, followed by the formation of a diamond structure on the second surface, and then the formation of a device structure on the substrate. This allows for the formation of a complete substrate before the device structure is formed, and the device structure can be formed on either the first or the second surface, thus better meeting different needs.

[0045] In some possible implementations, there are multiple first grooves and multiple second grooves, with each of the multiple first grooves and multiple second grooves corresponding one-to-one, and the diamond material in the first grooves and the second grooves has at least one of the following shapes: frustum structure, prismatic structure, bowl-shaped structure, cylindrical structure, and prismatic structure.

[0046] In some possible implementations, the number of second grooves is less than the number of first grooves, and there are multiple first grooves connected to the same second groove, wherein the first groove is at least one of a frustum structure, a truncated pyramid structure, a bowl-shaped structure, a cylindrical structure, and a prism structure.

[0047] In some possible implementations, if there is only one second trench, then if the second trench is formed after the first trench, the bottom of the second trench exposes all or part of the diamond material in the first trench; if the second trench is formed before the first trench, the bottoms of the plurality of first trenches expose the diamond material in the second trench.

[0048] In some possible implementations, the second trench is a plurality of trenches extending in a predetermined direction parallel to the surface of the substrate. If the second trench is formed after the first trench, at least one second trench has its bottom exposed with diamond material from the plurality of first trenches. If the second trench is formed before the first trench, the bottoms of the plurality of first trenches all expose with diamond material from the same second trench.

[0049] In some possible implementations, before etching the second surface of the substrate to form the second trench, the method further includes:

[0050] The substrate is thinned from its second surface.

[0051] A fourth aspect of this application provides a power amplifier chip, including the semiconductor device described in the first aspect of this application.

[0052] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:

[0053] This application provides a semiconductor device and its manufacturing method. The semiconductor device may include a substrate, an epitaxial layer, and electrodes located on the substrate. The substrate has a longitudinally penetrating diamond structure, which can be divided into a first diamond portion and a second diamond portion below the first diamond portion. The first and second diamond portions have different lateral dimensions. Due to the good thermal conductivity of the diamond structure, the penetrating diamond structure can form a longitudinal heat conduction channel, thereby efficiently conducting the heat generated during device operation to the device periphery, improving the heat dissipation performance of the semiconductor device, and facilitating the effective utilization of the high-power performance of the semiconductor device. Furthermore, the different lateral dimensions of the first and second diamond portions can be achieved through a two-stage etching process, reducing the etching aspect ratio, which facilitates control over the structure of the first and second diamond portions. Simultaneously, it can balance heat dissipation performance and lattice matching between epitaxial layers, resulting in a higher quality epitaxial layer and a high-performance semiconductor device. Moreover, the semiconductor device manufacturing process is simple and less difficult, and the substrate is easy to mass-produce. Attached Figure Description

[0054] To clearly understand the specific embodiments of this application, the accompanying drawings used in describing the specific embodiments of this application will be briefly described below. Obviously, these drawings are only some embodiments of this application.

[0055] Figure 1 A schematic diagram of a base station provided in an embodiment of this application;

[0056] Figure 2A This is a schematic diagram of the structure of a semiconductor device provided in an embodiment of this application;

[0057] Figure 2B This is a schematic diagram of the structure of another semiconductor device provided in an embodiment of this application;

[0058] Figure 3 This is a schematic diagram of the structure of another semiconductor device provided in the embodiments of this application;

[0059] Figure 4 A flowchart illustrating a method for manufacturing a semiconductor device as provided in this application embodiment;

[0060] Figures 5-12 This is a schematic diagram of the device structure in a method for manufacturing a semiconductor device according to an embodiment of this application;

[0061] Figure 13 A flowchart illustrating another method for manufacturing a semiconductor device provided in this application embodiment. Detailed Implementation

[0062] This application provides a semiconductor device and its manufacturing method, which improves the heat dissipation performance of the semiconductor device and facilitates the effective utilization of the high power performance of the semiconductor device.

[0063] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0064] This application is described in detail with reference to the schematic diagrams. When detailing the embodiments of this application, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this application. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0065] In semiconductor devices, the heat dissipation performance of the substrate is an important factor affecting device performance. In some scenarios, the high power performance of semiconductor devices cannot be effectively utilized due to the limitations of substrate heat dissipation.

[0066] For example, gallium nitride (GaN), as a third-generation wide-bandgap semiconductor material, possesses advantages such as high two-dimensional electron gas concentration and breakdown voltage, as well as high electron saturation velocity. These advantages provide favorable conditions for nitride device structures to function as high-power devices. However, due to limitations in substrate heat dissipation, the high-power performance of semiconductor devices cannot be effectively realized. This is because current substrates mostly use silicon-based and sapphire materials, which have poor thermal conductivity. When semiconductor devices output power, they generate a large amount of heat, and the low thermal conductivity of the substrate material cannot dissipate this heat in time, thus limiting the performance of semiconductor functional devices. Typically, sapphire has a thermal conductivity of 30-40 W / mk, silicon substrates have a thermal conductivity of 130-150 W / mk, and single-crystal silicon carbide (SiC) substrates with a 4H structure (denoted as 4H-SiC substrates) have a thermal conductivity range of 280-370 W / mk. The thermal conductivity of silicon carbide is several times that of traditional silicon or sapphire substrates. Even so, it cannot meet the heat dissipation requirements of high-power gallium nitride (GaN) electronic devices, thus limiting the high-power performance of GaN high-power devices to some extent.

[0067] With the trend towards higher frequency and higher power, gallium nitride-based HEMTs are increasingly being used in power amplifier (PA) chips for 5G applications. The following section introduces the application scenarios of PAs. (Reference) Figure 1 The diagram shown is a schematic of a base station according to an embodiment of this application. The active antenna unit (AAU) of the base station may include components such as a digital-to-analog converter (DAC), a radio frequency (RF) unit, a power amplifier (PA), and an antenna. The main digital information in the AAU is converted into analog signals by the DAC, modulated into high-frequency signals by the RF unit, and finally amplified to sufficient power by the power amplifier before being transmitted by the antenna unit. In the overall power consumption of the base station, the PA is one of the major power consumption units. For 5G base stations, a significant portion of the PA's power consumption is dissipated as heat. Therefore, the PA needs better heat dissipation to ensure the safety of the RF PA chip. If high levels of heat cannot be dissipated from the device in a timely manner, it will have a fatal impact on the PA, reducing its reliability and potentially causing it to fail. For example, if the antenna's RF output power is 100W, and the power efficiency of the PA is 50%, then the PA's power consumption needs to be 200W, with 100W of energy being consumed as heat. If the PA's power efficiency is 30%, then the PA's power consumption needs to be 333W, with 233W of energy being consumed as heat. This places very high demands on the device's heat dissipation.

[0068] One approach to solving the heat dissipation problem of high-power devices is to find a material with good thermal conductivity as its substrate, allowing the epitaxial layer material to be grown directly on this material, or to effectively bond the two together to achieve good heat dissipation. Research has found that diamond has excellent thermal conductivity (500–2000 W / mK), and using diamond as the substrate for high-power semiconductor devices can effectively solve their heat dissipation problems. For example, using diamond as the substrate for HEMT devices has already achieved excellent performance with output power exceeding 10 W / mm at 10 GHz.

[0069] However, using diamond as a device substrate presents several challenges. For example, directly growing epitaxial layers on a diamond substrate presents significant challenges, including difficulties in epitaxial growth, which affects film formation and leads to poor electrical performance. Furthermore, diamond substrates are typically small, making large-scale industrial mass production difficult. Bonding diamond substrates to the back of semiconductor devices requires interfacial bonding materials with low thermal conductivity, reducing overall heat dissipation and hindering the full realization of the device's performance advantages.

[0070] Based on the above technical problems, this application provides a semiconductor device and its manufacturing method. The semiconductor device may include a substrate, an epitaxial layer, and electrodes located on the substrate. The substrate has a longitudinally penetrating diamond structure, which includes a first diamond portion and a second diamond portion below the first diamond portion. The first and second diamond portions have different lateral dimensions. Due to the good thermal conductivity of the diamond structure, the penetrating diamond structure can form a longitudinal heat conduction channel, thereby efficiently conducting the heat generated during device operation to the device periphery, improving the heat dissipation performance of the semiconductor device, and facilitating the effective utilization of the high-power performance of the semiconductor device. Furthermore, the different lateral dimensions of the first and second diamond portions can be achieved through a two-stage etching process, reducing the etching aspect ratio, which facilitates control over the structure of the first and second diamond portions. Simultaneously, it can balance heat dissipation performance and lattice matching between epitaxial layers, resulting in a higher quality epitaxial layer and a high-performance semiconductor device. Moreover, the semiconductor device manufacturing process is simple and less difficult, and the substrate is easy to mass-produce.

[0071] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0072] refer to Figure 2A , Figure 2B and Figure 3 The diagram shown is a schematic diagram of the structure of a semiconductor device provided in an embodiment of this application. The semiconductor device may include a substrate 100, an epitaxial layer 200, and electrodes 401 / 402 / 403 from bottom to top.

[0073] In this embodiment, the substrate 100 is a component that provides support for the device and has certain thermal conductivity, enabling it to dissipate the heat generated during device operation to the outside of the device. The substrate 100 can be a semi-insulating semiconductor material. Specifically, the material of the substrate 100 can be one or more of silicon, silicon carbide, aluminum nitride, and sapphire. The following description will use silicon carbide as an example of the material of the substrate 100. Specifically, it can be single-crystal 4H-SiC. The thermal conductivity of single-crystal 4H-SiC substrate material is generally between 280-370 W / mK. This thermal conductivity limits the high power performance of semiconductor devices.

[0074] In this embodiment, the substrate 100 may have a diamond structure 110 that extends longitudinally through the substrate. The diamond structure 110 is either single-crystal diamond or polycrystalline diamond. Since diamond has good thermal conductivity (500-2000 W / mk), the diamond structure 110 extending longitudinally through the substrate 100 can form a longitudinal heat dissipation channel, thus greatly improving the heat dissipation efficiency of the device.

[0075] The diamond structure 110 can be longitudinally divided into a first diamond portion 112 and a second diamond portion 113, wherein the second diamond portion 113 is located below the first diamond portion 112. The first diamond portion 112 and the second diamond portion 113 have different lateral dimensions. For example, the lateral dimension of the first diamond portion 112 is larger than that of the second diamond portion 113, or the lateral dimension of the first diamond portion 112 is smaller than that of the second diamond portion 113, or the first diamond portion 112 and the second diamond portion 113 have different structures and thus different dimensional characteristics. Here, "lateral" refers to the direction along the substrate surface, and "longitudinal" refers to the direction perpendicular to the substrate surface, which is also the direction in which the substrate 100 and the epitaxial layer 200 are stacked. Figure 2A , Figure 2B and Figure 3 In the diagram, the horizontal direction can be either horizontal or perpendicular to the paper, and the vertical direction can be vertical. The first diamond portion 112 can have the same or different horizontal dimensions at different heights, and the second diamond portion 113 can also have the same or different horizontal dimensions at different heights. The first diamond portion 112 and the second diamond portion 113 are connected vertically, and the contact points can have the same or different horizontal dimensions.

[0076] In this embodiment, the difference in lateral dimensions of the first diamond portion 112 and the second diamond portion 113 can specifically be either completely different or not completely different. Specifically, it can be divided into several cases: First, the first diamond portion 112 has the same lateral dimension at different heights, the second diamond portion 113 has the same lateral dimension at different heights, and the lateral dimensions of the first diamond portion 112 and the second diamond portion 113 are different, then they are completely different; Second, one of the first diamond portion 112 and the second diamond portion 113 has the same lateral dimension at different heights, and the other has a different lateral dimension at different heights, then the lateral dimensions of the first diamond portion 112 and the second diamond portion 113 are completely different or not completely different; Third, the first diamond portion 112 has different lateral dimensions at different heights, the second diamond portion 113 has different lateral dimensions at different heights, and the lateral dimensions of the first diamond portion 112 and the second diamond portion 113 are completely different or not completely different. For example, they can have different shapes, which makes their lateral dimensions not completely different or completely different, or they can have the same shape, which makes their lateral dimensions not completely different or completely different.

[0077] Since the diamond structure 110 extends longitudinally through the substrate 100, the sum of the longitudinal dimensions of the first diamond portion 112 and the second diamond portion 113 is the same as the thickness of the substrate 100. In this embodiment, the thickness of the substrate 100 can be 50-100 μm, and the longitudinal dimensions of the first diamond portion 112 and the second diamond portion 113 can be determined according to the shape of the first diamond portion 112 and the second diamond portion 113.

[0078] Specifically, there can be multiple first diamond portions 112 and multiple second diamond portions 113, and each first diamond portion 112 corresponds to one second diamond portion 113. That is, one first diamond portion 112 can be connected to one second diamond portion 113 to form a diamond structure 110 penetrating the substrate 100. The shapes of the first diamond portions 112 and the second diamond portions 113 can be at least one of the following: frustum, truncated pyramid, bowl-shaped, cylindrical, and prismatic. That is, the shapes of the first diamond portions 112 and the second diamond portions 113 can be the same or different. When the first diamond portion 112 is a frustum, truncated pyramid, or bowl-shaped structure, it can have different lateral dimensions at different heights. Usually, the end with the larger lateral dimension is located in the surface direction of the substrate 10. When the second diamond portion 113 is a frustum, truncated pyramid, or bowl-shaped structure, it can have different lateral dimensions at different heights. Usually, the end with the larger lateral dimension is located in the surface direction of the substrate 10. When the first diamond portion 112 is a frustum, truncated pyramid, or bowl-shaped structure, the angle between the sidewall of the first diamond portion 112 and the substrate surface is 10-80°, specifically, it can be 30-60°. The angle between the sidewall of the bowl-shaped structure and the surface of the substrate 100 can be defined as the angle between the line connecting the bottom center point and the upper edge of the bowl-shaped structure and the substrate surface. The second diamond portion 113 has similar characteristics.

[0079] refer to Figure 2A As shown, the first diamond portion 112 can be a frustum structure, and the second diamond portion 113 can be a cylindrical structure. Of course, the first diamond portion 112 and the second diamond portion 113 can be cylindrical structures with different diameters (see reference). Figure 2BAs shown, the diameter of the first diamond portion 112 can be larger than the diameter of the second diamond portion 113 (or other structures). The longitudinal dimension of the first diamond portion 112 can be 1-10 μm, the lateral dimension of the first diamond portion 112 can be 1-10 μm, the spacing between the first diamond portions 112 can be 1-10 μm, and the lateral dimension of the second diamond portion 113 can be 5-20 μm. When the first diamond portion 112 has different lateral dimensions at different heights, the above dimensions represent the dimensions of the first diamond portion 112 on the substrate surface. When the second diamond portion 113 has different lateral dimensions at different heights, the above dimensions represent the dimensions of the second diamond portion 113 on the substrate surface. Wherein, when the first diamond portion 112 is circular on the substrate surface, its dimension is its diameter; when the first diamond portion 112 is polygonal on the substrate surface, its dimension is its side length. The second diamond portion 113 has similar characteristics.

[0080] Specifically, the first diamond portion 112 and the second diamond portion 113 may not correspond one-to-one. The number of second diamond portions 113 may be less than the number of first diamond portions 112, resulting in multiple first diamond portions 112 connected to the same second diamond portion 113. The shape of the first diamond portion 112 can be at least one of the following: frustum, prismatic, bowl-shaped, cylindrical, and prismatic. The shapes of all the first diamond portions 112 may be identical or different. (Reference) Figure 3 As shown, the second diamond portion 113 can be an integral structure. The second diamond portion 113 can be longitudinally connected to each of the first diamond portions 112, or only longitudinally connected to a portion of the first diamond portions 112. Alternatively, there can be multiple second diamond portions 113, and the second diamond portions 113 extend in a predetermined direction parallel to the substrate surface. At least one second diamond portion 113 is longitudinally connected to multiple first diamond portions 112, thereby forming a bottom-to-top through structure.

[0081] An epitaxial layer 200 can be formed on the substrate 100. In a GaN-based HEMT device, the epitaxial layer 200 may include a buffer layer and a barrier layer. The buffer layer and the barrier layer can form a heterostructure, thereby generating a two-dimensional electron gas. The semiconductor device formed can operate using the two-dimensional electron gas generated by this heterostructure. Of course, the semiconductor device in this embodiment can also be other energy devices or lasers, in which case the epitaxial layer is an epitaxial layer in other devices, which will not be listed here. The buffer layer can be a gallium nitride layer, and the barrier layer can be made of at least one of AlGaN, InAlN, AlN, and ScAlN. The thickness of the buffer layer can range from 0.1 to 2 μm, and the thickness of the barrier layer can range from 5 to 20 nm. Since the substrate 100 is a silicon carbide substrate, and part of the diamond structure is exposed on the substrate surface, the lattice matching degree between the gallium nitride layer and the substrate 100 is high. Therefore, the gallium nitride layer has good epitaxial quality, which is beneficial for forming high-performance devices. Gallium nitride (GaN) layers can include low-temperature GaN layers and high-temperature GaN layers, wherein the low-temperature GaN layer serves as a buffer layer between the high-temperature GaN layer and the substrate, thereby improving the epitaxial quality of the high-temperature GaN layer.

[0082] Electrodes 401 / 402 / 403 can be formed on the epitaxial layer 200. The electrodes may include a source 401, a drain 403, and a gate 402. The gate 402 may be located between the source 401 and the drain 403. The material of the electrodes 401 / 402 / 403 may be a metallic material, such as at least one of Au, Ti, Al, Ni, and Ta. As a possible implementation, the material of the electrodes may be an Au, Ti / Al / Ni / Au stack, or a Ta / Al / Ta stack.

[0083] This application provides a semiconductor device, which may include a substrate, an epitaxial layer, and electrodes located on the substrate. The substrate has a longitudinally penetrating diamond structure, comprising a first diamond portion and a second diamond portion below the first diamond portion. The first and second diamond portions have different lateral dimensions. Due to the good thermal conductivity of the diamond structure, the penetrating diamond structure can form a longitudinal heat conduction channel, thereby efficiently conducting the heat generated during device operation to the device periphery, improving the heat dissipation performance of the semiconductor device, and facilitating the effective utilization of the high-power performance of the semiconductor device. Furthermore, the different lateral dimensions of the first and second diamond portions can be achieved through a two-stage etching process, reducing the etching aspect ratio, facilitating control over the structure of the first and second diamond portions, and simultaneously considering both heat dissipation performance and lattice matching between epitaxial layers, resulting in higher quality epitaxial layers and high-performance semiconductor devices. At the same time, the semiconductor device manufacturing process is simple and less difficult, and the substrate is easy to mass-produce.

[0084] Based on the semiconductor device provided in the above embodiments, this application also provides a method for manufacturing a semiconductor device, referencing... Figure 4 The diagram shown is a flowchart of a method for manufacturing a semiconductor device using a substrate 100, according to an embodiment of this application. Figures 5-12 As a schematic diagram of the device structure during device manufacturing, this method can first form a first diamond portion 112 of a diamond structure in a substrate 100, then form the device structure thereon, and then form a second diamond portion 113 of the diamond structure in the substrate 100. Specifically, the method may include:

[0085] S101, providing substrate 100, reference Figure 5 As shown.

[0086] In this embodiment, the substrate 100 is a component that provides support for the device and has certain thermal conductivity, enabling it to dissipate the heat generated during device operation to the outside of the device. The substrate 100 can be a semi-insulating semiconductor material. Specifically, the material of the substrate 100 can be one or more of silicon, silicon carbide, aluminum nitride, and sapphire. The following description will use silicon carbide as an example of the material of the substrate 100. Specifically, it can be single-crystal 4H-SiC. The thermal conductivity of single-crystal 4H-SiC substrate material is generally between 280-370 W / mK. This thermal conductivity limits the high power performance of semiconductor devices.

[0087] S102, the first surface of the substrate 100 is etched to obtain a first trench 101, and the first trench 101 is filled with diamond material, reference. Figures 6-8 As shown.

[0088] In this embodiment of the application, the first trench 101 can be obtained by etching the first surface of the substrate 100, as shown in the reference. Figure 6 As shown, the first groove 101 is filled with diamond material. The diamond material filled in the first groove 101 can serve as the first diamond portion 112 in the aforementioned embodiment. (Refer to...) Figure 8 As shown. The etching of the substrate 100 can be performed using dry anisotropic etching, such as plasma etching. The first trench 101 obtained by etching has a lateral dimension of 1-10 μm and an etching depth of 1-10 μm. The spacing between different first trenches 101 ranges from 1-10 μm, and the first trenches 101 can form a periodic array arrangement.

[0089] The shape of the first trench 101 can be controlled by controlling the etching parameters of the substrate 100. The shape of the first trench 101 can be at least one of the following: frustum structure, prismatic structure, bowl structure, cylindrical structure, and prismatic structure. The larger end of the frustum structure, prismatic structure, and bowl structure faces the substrate surface. During the etching process, the etching rate can be slowed down to reduce the damage of the etching gas to the sidewalls of the first trench 101, thereby forming a structure that is larger at the top and smaller at the bottom of the first trench 101.

[0090] After etching to form the first trench 101, diamond material, which can be single-crystal diamond or polycrystalline diamond, can be filled into the first trench 101. Specifically, diamond material can be grown on the substrate 100 where the first trench 101 is formed. After a period of growth, a high-quality polycrystalline diamond layer 111 with a thickness of 1-50 μm can be formed on the substrate. Figure 7 As shown. Then, by grinding and polishing, part of the diamond layer 111 is removed, exposing the surface of the substrate 100. In this way, the diamond material is formed only in the first trench 101, and the size of the diamond material is the same as or approximately the size of the first trench 101. (Refer to...) Figure 8 As shown. Diamond materials can be grown using microwave plasma chemical vapor deposition (MPCVD). The growth temperature range is 800-1200℃, and the pressure range is 1-15 kPa. MPCVD offers advantages such as stable plasma discharge and minimal contamination, enabling the growth of high-quality diamond materials.

[0091] S103, an epitaxial layer 200 and electrodes 401 / 402 / 403 are sequentially formed on the first surface of the substrate 100, reference. Figures 9-10 .

[0092] An epitaxial layer 200 may be formed on the first surface of the substrate 100, as shown in the reference. Figure 9 As shown, when the semiconductor device is a GaN-based HEMT device, the epitaxial layer 200 may include a buffer layer and a barrier layer. The buffer layer and the barrier layer can form a heterostructure, thereby generating a two-dimensional electron gas. The resulting semiconductor device can operate using the two-dimensional electron gas generated by this heterostructure. The buffer layer can be a gallium nitride layer, and the barrier layer can be made of at least one of AlGaN, InAlN, AlN, and ScAlN. The thickness of the buffer layer can range from 0.1 to 2 μm, and the thickness of the barrier layer can range from 5 to 20 nm.

[0093] Specifically, a buffer layer can be formed on the first surface of the substrate 100, and then a barrier layer can be formed on the buffer layer. The gallium nitride (GaN) layer can be formed using metal-organic chemical vapor deposition (MOCVD). Due to the severe lattice mismatch between diamond and GaN, GaN grows faster on silicon carbide but slower or even impossible on diamond. This strengthens the lateral growth of GaN on silicon carbide and promotes dislocation merging, resulting in a higher-quality GaN layer. When the diamond material formed in the first trench has a frustum, truncated pyramid, or bowl-shaped structure, it is more conducive to the growth of GaN on the substrate, resulting in a higher-quality GaN layer. The GaN layer can include a low-temperature GaN layer and a high-temperature GaN layer. The low-temperature GaN layer serves as a buffer layer between the high-temperature GaN layer and the substrate, improving the epitaxial quality of the high-temperature GaN layer. The barrier layer can also be formed using MOCVD.

[0094] Electrodes 401 / 402 / 403 can be formed on the epitaxial layer 200. Electrodes 401 / 402 / 403 may include a source 401, a drain 403, and a gate 402. The gate 402 may be located between the source 401 and the drain 403. Figure 10 As shown, the material of electrodes 401 / 402 / 403 can be a metallic material, such as at least one of Au, Ti, Al, Ni, and Ta. As one possible implementation, the material of electrodes 401 / 402 / 403 can be Au, Ti / Al / Ni / Au stack, or Ta / Al / Ta stack.

[0095] S104, the second surface of the substrate 100 is etched to obtain a second trench 102. The second trench 102 is connected to the first trench 101 but has different lateral dimensions. The second trench 102 is filled with diamond material. (Refer to...) Figure 11 , Figure 12 , Figure 2A , Figure 2B and Figure 3 .

[0096] After forming electrodes 401 / 402 / 403, a dielectric layer can be formed to cover electrodes 401 / 402 / 403 to provide protection for the electrodes (not shown in the figure). Then, the second surface of the substrate 100 can be etched to obtain the second trench 102. The first and second surfaces are two opposing surfaces, as shown in the reference. Figure 11 and Figure 12As shown, diamond material is filled in the second trench 102. The diamond material in the second trench 102 can serve as the second diamond portion 113 in the aforementioned embodiment. The first trench 101 and the second trench 102 are connected, and the diamond material in the first trench 101 and the diamond material in the second trench 102 contact to form a diamond structure 110 that penetrates the substrate. (Refer to...) Figure 2A , Figure 2B and Figure 3 As shown. Because the lateral dimensions of the first trench 101 and the second trench 102 are different, the lateral dimensions of the first diamond portion 112 and the second diamond portion 113 of the formed diamond structure are also different. Since diamond has excellent thermal conductivity, the diamond structure penetrating the substrate longitudinally can form a longitudinal heat dissipation channel, which can greatly improve the heat dissipation efficiency of the device. Before etching the second surface of the substrate 100, the substrate 100 can be thinned from the second surface, so that the thickness of the substrate 100 is in the range of 50-100 μm, and the sum of the longitudinal dimensions of the first diamond portion 112 and the second diamond portion 113 is the same as the thickness of the substrate 100.

[0097] In practice, after the device is formed, chip bonding can be performed. At this time, the chip is flipped so that the substrate faces upward to achieve bonding. Therefore, the etching of the second surface of the substrate described above is compatible with the actual operation steps, and higher performance devices can be obtained without adding too many steps.

[0098] Specifically, there can be multiple first trenches 101 and second trenches 102. The first trenches 101 and second trenches 102 can correspond one-to-one. One first trench 101 can be connected to one second trench 102, forming a through-hole penetrating the substrate. (Refer to...) Figure 11 As shown. The first trench 101 and the second trench 102 can have shapes that are at least one of a frustum, a truncated pyramid, a bowl-shaped structure, a cylindrical structure, and a prism. The shapes of the first trench 101 and the second trench 102 can be the same or different. When the first diamond portion 112 is a frustum, a truncated pyramid, or a bowl-shaped structure, the end with the larger lateral dimension is usually located in the direction of the substrate surface. When the second diamond portion 113 is a frustum, a truncated pyramid, or a bowl-shaped structure, the end with the larger lateral dimension is usually located in the direction of the substrate surface. When the first trench 101 is a frustum, a truncated pyramid, or a bowl-shaped structure, the angle between the sidewall of the first trench 101 and the substrate surface is 10-80°, specifically, it can be 30-60°. The angle between the sidewall of the bowl-shaped structure and the substrate surface can be defined as the angle between the line connecting the bottom center point and the top edge of the bowl-shaped structure and the substrate surface. The second diamond portion 113 has similar characteristics.

[0099] The second trench 102 has a lateral dimension ranging from 5-20 μm and a longitudinal dimension ranging from 40-99 μm. When the first trench 101 has different lateral dimensions at different heights, these dimensions represent the opening size of the first trench 101 on the substrate surface. Similarly, when the second trench 102 has different lateral dimensions at different heights, these dimensions represent the opening size of the second trench 102 on the substrate surface. When the first trench 101 is circular on the substrate surface, its dimension is its diameter; when it is polygonal, its dimension is its side length. The second trench 102 has similar characteristics.

[0100] Specifically, the first groove 101 and the second groove 102 may not correspond one-to-one. The number of second grooves 102 may be less than the number of first grooves 101, resulting in multiple first grooves 101 connected to the same second groove 102. The shape of the first groove 101 can be at least one of the following: frustum, prismatic, bowl-shaped, cylindrical, and prismatic. (Refer to...) Figure 12 As shown. Reference Figure 12 As shown, the second trench 102 can be an integral structure. The second trench 102 can be longitudinally connected to each of the first trenches 101, or only longitudinally connected to a portion of the first diamond portion 112. That is, the bottom of the second trench 102 can expose all or part of the diamond material in the first trenches 101. There can also be multiple second trenches 102, and the second trenches 102 extend in a predetermined direction parallel to the substrate surface. At least one second trench 102 is longitudinally connected to multiple first trenches 101, thereby forming a bottom-to-top through structure. That is, at least one second trench 102 exposes the diamond material in multiple first trenches 101 at its bottom.

[0101] In this scenario, a large area of ​​etching can be performed on the second surface of the substrate to remove most of the material, resulting in a cavity structure as the second trench 102. This cavity structure exposes the diamond material in the first trench 101. After the second trench 102 is filled with diamond material, the diamond material in the first trench 101 and the diamond material in the second trench 102 come into contact, forming a diamond structure that penetrates the substrate and creates a longitudinal heat conduction path. The first diamond portion 112 of the diamond structure contacts the epitaxial layer on the substrate, while the second diamond portion 113 of the diamond structure is exposed outside the substrate, allowing heat generated inside the device to be conducted to the outside. A heat sink can also be placed below the substrate, allowing the second diamond portion 113 of the diamond structure to contact the heat sink and quickly conduct heat to it, achieving rapid heat dissipation of the device. When the second trench 102 is a large-area cavity structure, the area of ​​the diamond structure exposed outside the substrate is large, resulting in a larger contact area with the heat sink, further improving heat dissipation efficiency.

[0102] It should be noted that the substrate 100 may contain a first trench 101 that is not connected to the second trench 102, which can serve as a third trench; or a second trench 102 that is not connected to the first trench 101, which can serve as a fourth trench. The third and fourth trenches do not penetrate the substrate 100, and the diamond material therein is only formed within a certain depth of the substrate 100. At this time, no heat dissipation channel is formed that penetrates vertically. However, the diamond material in the third and fourth trenches can still dissipate heat outward, for example, by conducting heat to other diamond materials through lateral heat conduction, or by dissipating heat downward so that the heat is directly diffused to the outside of the device, or by diffused to the outside of the device through the substrate 100, or by diffused to the outside of the device through the substrate 100 and other diamond materials.

[0103] This application provides a method for manufacturing a semiconductor device. A first trench is etched on a first surface of a substrate, and diamond material is filled into the first trench. An epitaxial layer and electrodes are sequentially formed on the first surface of the substrate. Then, a second trench is etched on a second surface of the substrate, forming a second trench that is connected to the first trench but has different lateral dimensions. Diamond material is also filled into the second trench, creating contact between the diamond material in the first and second trenches, forming a diamond structure that penetrates the substrate. Due to the good thermal conductivity of the diamond structure, this penetrating diamond structure can form a longitudinal heat conduction channel, efficiently conducting heat generated during device operation to the device periphery, improving the heat dissipation performance of the semiconductor device, and facilitating the effective utilization of its high-power performance. Furthermore, the difference in lateral dimensions between the first and second diamond portions can be achieved through a two-stage etching process, reducing the etching aspect ratio and allowing for better control of the structure of the first and second diamond portions. This balances heat dissipation performance and lattice matching between epitaxial layers, resulting in higher-quality epitaxial layers and ultimately, high-performance semiconductor devices. Meanwhile, semiconductor devices have simple manufacturing processes, are easy to manufacture, and their substrates are easy to mass-produce.

[0104] Based on the semiconductor device provided in the above embodiments, this application also provides a method for manufacturing a semiconductor device, referencing... Figure 13 The diagram shown is a flowchart of another semiconductor device manufacturing method provided in this application embodiment. In this method, a first diamond portion 112 and a second diamond portion 113 in a diamond structure can be formed in a substrate 100 first, and then a device structure can be formed thereon. Specifically, the method may include:

[0105] S201 provides substrate 100.

[0106] In this embodiment, the substrate 100 is a component that provides support for the device and has certain thermal conductivity, enabling it to dissipate the heat generated during device operation to the outside of the device. The substrate 100 can be a semi-insulating semiconductor material. Specifically, the material of the substrate 100 can be one or more of silicon, silicon carbide, aluminum nitride, and sapphire. The following description will use silicon carbide as an example of the material of the substrate 100. Specifically, it can be single-crystal 4H-SiC. The thermal conductivity of single-crystal 4H-SiC substrate material is generally between 280-370 W / mK. This thermal conductivity limits the high power performance of semiconductor devices.

[0107] S202, etching the first surface of the substrate 100 to obtain a first trench 101, and filling the first trench 101 with diamond material; and etching the second surface of the substrate 100 to obtain a second trench 102, the second trench 102 being connected to the first trench 101 and having different lateral dimensions, and filling the second trench 102 with diamond material.

[0108] In this embodiment, a first trench 101 can be obtained by etching the first surface of the substrate 100, and diamond material can be filled into the first trench 101. The diamond material filled into the first trench 101 can serve as the first diamond portion 112 in the aforementioned embodiment. The etching of the substrate 100 can be performed using dry anisotropic etching, such as plasma etching. The lateral dimension of the etched first trench 101 is 1-10 μm, the etching depth is 1-10 μm, the spacing between different first trenches 101 is 1-10 μm, and the first trenches 101 can form a periodic array arrangement.

[0109] The shape of the first trench 101 can be controlled by controlling the etching parameters of the substrate 100. The shape of the first trench 101 can be at least one of the following: frustum structure, prismatic structure, bowl structure, cylindrical structure, and prismatic structure. The larger end of the frustum structure, prismatic structure, and bowl structure faces the substrate surface. During the etching process, the etching rate can be slowed down to reduce the damage of the etching gas to the sidewalls of the first trench 101, thereby forming a structure that is larger at the top and smaller at the bottom of the first trench 101.

[0110] After etching to form the first trench 101, diamond material, either single-crystal or polycrystalline diamond, can be filled into the first trench 101. Specifically, diamond material can be grown on the substrate 100 where the first trench 101 is formed. After a period of growth, a high-quality polycrystalline diamond layer 111 with a thickness of 1-50 μm can be formed on the substrate 100. Then, part of the diamond layer 111 is removed by grinding and polishing, exposing the surface of the substrate 100. In this way, the diamond material is formed only in the first trench 101, and the size of the diamond material is the same as or approximately the size of the first trench 101. The diamond material can be grown by MPCVD, with a growth temperature range of 800-1200℃ and a pressure range of 1-15 kPa. The MPCVD method has advantages such as stable plasma discharge and low contamination, and can grow high-quality diamond materials.

[0111] In this embodiment, the second surface of the substrate 100 can be etched to obtain a second trench 102, and diamond material can be filled into the second trench 102. The first surface and the second surface are two opposing surfaces. The diamond material in the second trench 102 can serve as the second diamond portion 113 in the aforementioned embodiment. The first trench 101 and the second trench 102 are connected, and the diamond material in the first trench 101 and the diamond material in the second trench 102 contact to form a diamond structure penetrating the substrate 100. Since the lateral dimensions of the first trench 101 and the second trench 102 are different, the lateral dimensions of the first diamond portion 112 and the second diamond portion 113 of the formed diamond structure are also different. Because diamond has good thermal conductivity, the diamond structure penetrating the substrate 100 longitudinally can form a longitudinal heat dissipation channel, which can greatly improve the heat dissipation efficiency of the device. Before etching the second surface of the substrate 100, the substrate 100 can be thinned from the second surface of the substrate 100, so that the thickness of the substrate 100 is in the range of 50-100um, and the sum of the longitudinal dimensions of the first diamond portion 112 and the second diamond portion 113 is the same as the thickness of the substrate 100.

[0112] It should be noted that the etching order of the first trench 101 and the second trench 102 can be arbitrary. If the first trench 101 is etched before the second trench 102, then diamond material needs to be filled in the first trench 101 before the second trench 102 is etched, and the bottom of the second trench 102 exposes the diamond material in the first trench 101. If the second trench 102 is etched before the first trench 101, then diamond material needs to be filled in the second trench 102 before the first trench 101 is etched, and the bottom of the first trench 101 exposes the diamond material in the second trench 102.

[0113] Specifically, the first trench 101 and the second trench 102 can correspond one-to-one, with one first trench 101 communicating with one second trench 102 to form a through-hole penetrating the substrate 100. The shapes of the first trench 101 and the second trench 102 can be at least one of a frustum, truncated pyramid, bowl-shaped, cylindrical, and prismatic structure. The shapes of the first trench 101 and the second trench 102 can be the same or different. When the first diamond portion 112 is a frustum, truncated pyramid, or bowl-shaped structure, the end with the larger lateral dimension is typically located on the surface of the substrate 100. Similarly, when the second diamond portion 113 is a frustum, truncated pyramid, or bowl-shaped structure, the end with the larger lateral dimension is typically located on the surface of the substrate 100. When the first trench 101 is a frustum structure, a truncated pyramid structure, or a bowl-shaped structure, the angle between the sidewall of the first trench 101 and the substrate surface is 10-80°, specifically, it can be 30-60°. The angle between the sidewall of the bowl-shaped structure and the substrate surface can be defined as the angle between the line connecting the bottom center point and the upper edge of the bowl-shaped structure and the substrate surface. The second diamond portion 113 has similar characteristics.

[0114] The second trench 102 has a lateral dimension ranging from 5-20 μm and a longitudinal dimension ranging from 40-99 μm. When the first trench 101 has different lateral dimensions at different heights, these dimensions represent the opening size of the first trench 101 on the substrate surface. Similarly, when the second trench 102 has different lateral dimensions at different heights, these dimensions represent the opening size of the second trench 102 on the substrate surface. When the first trench 101 is circular on the substrate surface, its dimension is its diameter; when it is polygonal, its dimension is its side length. The second trench 102 has similar characteristics.

[0115] Specifically, the first groove 101 and the second groove 102 may not correspond one-to-one. The number of second grooves 102 may be less than the number of first grooves 101. In this case, there may be multiple first grooves 101 connected to the same second groove 102. The shape of the first groove 101 may be at least one of the following: frustum structure, prismatic structure, bowl-shaped structure, cylindrical structure, and prismatic structure.

[0116] The second trench 102 can be an integral structure, which can be longitudinally connected to all the first trenches 101, or longitudinally connected to only a portion of the first trenches 101. Specifically, if the second trench 102 is formed after the first trenches 101, the bottom of the second trench 102 can expose all or part of the diamond material in the first trenches 101; if the second trench 102 is formed before the first trenches 101, the bottoms of the multiple first trenches 101 all expose the diamond material in the second trench 102.

[0117] There can be multiple second trenches 102, and each second trench 102 extends in a predetermined direction parallel to the substrate surface. At least one second trench 102 is longitudinally connected to multiple first trenches 101, thereby forming a bottom-to-top through structure. Specifically, if the second trench 102 is formed before the first trenches 101, at least one second trench 102 exposes diamond material in multiple first trenches 101 at its bottom. If the second trench 102 is formed after the first trenches 101, multiple first trenches 101 expose diamond material in the same second trench 102 at their bottoms.

[0118] In this scenario, a large area of ​​etching can be performed on the second surface of the substrate 100 to remove most of the material, resulting in a cavity structure as the second trench 102. The first trench 101 and the second trench 102 are connected. After filling the first trench 101 and the second trench 102 with diamond material, the diamond material in the first trench 101 and the diamond material in the second trench 102 come into contact, forming a diamond structure that penetrates the substrate 100 and creating a vertical heat conduction path. The first diamond portion 112 of the diamond structure is in contact with the epitaxial layer on the substrate 100, while the second diamond portion 113 of the diamond structure is exposed outside the substrate 100, allowing heat generated inside the device to be conducted to the outside. A heat sink can also be placed below the substrate 100, allowing the second diamond portion 113 of the diamond structure to come into contact with the heat sink, rapidly conducting heat to the heat sink and achieving rapid heat dissipation of the device. When the second trench 102 is a large-area cavity structure, the diamond structure has a larger area exposed outside the substrate 100, and the contact area with the heat sink is also larger, which further improves the heat dissipation efficiency.

[0119] It should be noted that the substrate 100 may contain a first trench 101 that is not connected to the second trench 102, which can serve as a third trench; or a second trench 102 that is not connected to the first trench 101, which can serve as a fourth trench. The third and fourth trenches do not penetrate the substrate 100, and the diamond material therein is only formed within a certain depth of the substrate 100. At this time, no heat dissipation channel is formed that penetrates vertically. However, the diamond material in the third and fourth trenches can still dissipate heat outward, for example, by conducting heat to other diamond materials through lateral heat conduction, or by dissipating heat downward so that the heat is directly diffused to the outside of the device, or by diffused to the outside of the device through the substrate 100, or by diffused to the outside of the device through the substrate 100 and other diamond materials.

[0120] S203, an epitaxial layer 200 and electrodes 401 / 402 / 403 are sequentially formed on a substrate 100.

[0121] An epitaxial layer 200 can be formed on the substrate 100. When the semiconductor device is a GaN-based HEMT device, the epitaxial layer 200 may include a buffer layer and a barrier layer. The buffer layer and the barrier layer can form a heterostructure to generate a two-dimensional electron gas. The semiconductor device formed can operate using the two-dimensional electron gas generated by the heterostructure. The buffer layer can be a gallium nitride layer, and the barrier layer can be made of at least one of AlGaN, InAlN, AlN, and ScAlN. The thickness of the buffer layer can range from 0.1 to 2 μm, and the thickness of the barrier layer can range from 5 to 20 nm.

[0122] Specifically, a buffer layer can be formed on the first surface of the substrate 100, and then a barrier layer can be formed on the buffer layer. The gallium nitride (GaN) layer can be formed by MOCVD. Due to the severe lattice mismatch between diamond and GaN, GaN grows faster on silicon carbide but slower or even impossible on diamond. This strengthens the lateral growth of GaN on silicon carbide and promotes dislocation merging, resulting in a higher-quality GaN layer. When the diamond material formed in the first trench 101 has a frustum, truncated pyramid, or bowl-shaped structure, it is more conducive to the growth of GaN on the substrate 100, resulting in a higher-quality GaN layer. The GaN layer can include a low-temperature GaN layer and a high-temperature GaN layer. The low-temperature GaN layer serves as a buffer layer between the high-temperature GaN layer and the substrate 100, improving the epitaxial quality of the high-temperature GaN layer. The barrier layer can also be formed by MOCVD.

[0123] Electrodes 401 / 402 / 403 can be formed on the epitaxial layer 200. Electrodes 401 / 402 / 403 may include a source 401, a drain 403, and a gate 402. The gate 402 may be located between the source 401 and the drain 403. The material of electrodes 401 / 402 / 403 can be a metallic material, such as at least one of Au, Ti, Al, Ni, and Ta. As one possible implementation, the material of electrodes 401 / 402 / 403 can be an Au, Ti / Al / Ni / Au stack, or a Ta / Al / Ta stack. After forming electrodes 401 / 402 / 403, a dielectric layer can also be formed to cover the electrodes to provide protection for electrodes 401 / 402 / 403.

[0124] This application provides a method for manufacturing a semiconductor device. A first trench is etched on a first surface of a substrate and filled with diamond material. A second trench is etched on a second surface of the substrate, connecting the first and second trenches, but with different lateral dimensions. Diamond material is also filled in the second trench. An epitaxial layer and electrodes are then sequentially formed on the first surface of the substrate. The diamond material in the first and second trenches contacts each other, forming a diamond structure penetrating the substrate. Due to the good thermal conductivity of the diamond structure, this penetrating diamond structure forms a longitudinal heat conduction channel, efficiently conducting heat generated during device operation to the device periphery, improving the heat dissipation performance of the semiconductor device, and facilitating the effective utilization of its high-power performance. Furthermore, the difference in lateral dimensions between the first and second diamond portions can be achieved through a two-stage etching process, reducing the etching aspect ratio and allowing for better control of the structure of the first and second diamond portions. This balances heat dissipation performance and lattice matching between epitaxial layers, resulting in higher-quality epitaxial layers and high-performance semiconductor devices. Meanwhile, semiconductor devices have simple manufacturing processes, are easy to manufacture, and their substrates are easy to mass-produce.

[0125] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the method embodiments are basically similar to the structural embodiments, so they are described more simply; relevant parts can be referred to the descriptions of the structural embodiments.

[0126] The above describes the specific implementation of this application. It should be understood that the above embodiments are only used to illustrate the technical solutions of this application, and not 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; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A semiconductor device, characterized in that, include: A substrate having a diamond structure extending longitudinally through the substrate, the diamond structure being longitudinally divided into a first diamond portion and a second diamond portion below the first diamond portion, the first diamond portion and the second diamond portion having different lateral dimensions; the lateral dimension of the first diamond portion is greater than the lateral dimension of the second diamond portion, or the lateral dimension of the first diamond portion is smaller than the lateral dimension of the second diamond portion, or the first diamond portion and the second diamond portion have different structures; the contact position of the first diamond portion and the second diamond portion has different lateral dimensions, or the contact position of the first diamond portion and the second diamond portion has the same lateral dimension; The epitaxial layer and the electrode are sequentially located on the substrate.

2. The device according to claim 1, characterized in that, There are multiple first diamond portions and multiple second diamond portions, and each of the multiple first diamond portions and multiple second diamond portions corresponds to one other, and each of the following structures is at least one of frustum structure, prismatic structure, bowl structure, cylindrical structure and prismatic structure.

3. The device according to claim 1, characterized in that, The number of second diamond portions is less than the number of first diamond portions, and there are multiple first diamond portions connected to the same second diamond portion. The first diamond portion is at least one of a frustum structure, a prismatic structure, a bowl-shaped structure, a cylindrical structure, and a prismatic structure.

4. The device according to claim 3, characterized in that, The second diamond portion is one and is longitudinally connected to all or part of the first diamond portion.

5. The device according to claim 3, characterized in that, The second diamond portion is multiple, and the second diamond portion extends in a predetermined direction parallel to the surface of the substrate, and at least one second diamond portion is longitudinally connected to multiple first diamond portions.

6. The device according to any one of claims 1-5, characterized in that, The first diamond portion has a lateral dimension ranging from 1 to 10 μm, a longitudinal dimension ranging from 1 to 10 μm, a spacing between different first diamond portions ranging from 1 to 10 μm, and a substrate thickness ranging from 50 to 100 μm.

7. The device according to any one of claims 1-5, characterized in that, The substrate is made of one or more of silicon, silicon carbide, aluminum nitride, and sapphire.

8. The device according to any one of claims 1-5, characterized in that, The diamond structure is either single-crystal diamond or polycrystalline diamond.

9. The device according to any one of claims 1-5, characterized in that, The epitaxial layer includes a buffer layer and a barrier layer. The buffer layer is a gallium nitride layer, and the barrier layer is made of one or more of AlGaN, InAlN, AlN, and ScAlN.

10. The device according to claim 9, characterized in that, The thickness of the gallium nitride layer ranges from 0.1 to 2 μm, and the thickness of the barrier layer ranges from 5 to 20 nm.

11. The device according to any one of claims 1-5, characterized in that, The electrode includes a source, a drain, and a gate, and the material of the electrode is at least one of Au, Ti, Al, Ni, and Ta.

12. A method for forming a semiconductor device, characterized in that, include: Provide substrate; The first trench is obtained by etching the first surface of the substrate; The first trench is filled with diamond material; An epitaxial layer and an electrode are sequentially formed on the first surface of the substrate; After the epitaxial layer and the electrode are formed, the second surface of the substrate is etched to obtain a second trench. The second trench is connected to the first trench and has different lateral dimensions. The first surface and the second surface are two opposing surfaces. The number of second trenches is less than the number of first trenches, and there are multiple first trenches connected to the same second trench. The second groove is filled with diamond material.

13. The method according to claim 12, characterized in that, There are multiple first grooves and multiple second grooves, and the multiple first grooves and multiple second grooves correspond one-to-one. The diamond material in the first grooves and the second grooves is at least one of the following structures: frustum, prismatic, bowl-shaped, cylindrical, and prismatic.

14. The method according to claim 12, characterized in that, The first groove is shaped like one of the following: frustum, prismatic, bowl-shaped, cylindrical, and prismatic.

15. The method according to claim 14, characterized in that, The second trench is one, and the bottom of the second trench exposes all or part of the diamond material in the first trench.

16. The method according to claim 14, characterized in that, The second trench is a plurality of trenches extending in a predetermined direction parallel to the surface of the substrate, and at least one of the second trenches has diamond material exposed at the bottom of the plurality of first trenches.

17. The method according to any one of claims 12-16, characterized in that, Before etching the second surface of the substrate to obtain the second trench, the method further includes: The substrate is thinned from its second surface.

18. A method for forming a semiconductor device, characterized in that, include: Provide substrate; A first trench is obtained by etching from the first surface of the substrate, and the first trench is filled with diamond material; And etching a second trench from the second surface of the substrate, and filling the second trench with diamond material; The first trench and the second trench are connected, but have different lateral dimensions; The first surface and the second surface are two opposing surfaces; the number of second grooves is less than the number of first grooves, and there are multiple first grooves connected to the same second groove; After filling the first trench with diamond material and the second trench with diamond material, an epitaxial layer and an electrode are sequentially formed on the first surface of the substrate.

19. The method according to claim 18, characterized in that, There are multiple first grooves and multiple second grooves, and the multiple first grooves and multiple second grooves correspond one-to-one. The diamond material in the first grooves and the second grooves is at least one of the following structures: frustum, prismatic, bowl-shaped, cylindrical, and prismatic.

20. The method according to claim 18, characterized in that, The first groove is at least one of the following: frustum structure, prismatic structure, bowl-shaped structure, cylindrical structure, and prismatic structure.

21. The method according to claim 20, characterized in that, If there is one second groove, and the second groove is formed after the first groove, the bottom of the second groove exposes all or part of the diamond material in the first groove; if the second groove is formed before the first groove, the bottom of multiple first grooves exposes the diamond material in the second groove.

22. The method according to claim 20, characterized in that, The second trench is a plurality of trenches extending in a predetermined direction parallel to the surface of the substrate. If the second trench is formed after the first trench, at least one second trench has its bottom exposed with diamond material in the plurality of first trenches. If the second trench is formed before the first trench, the bottoms of the plurality of first trenches all expose with diamond material in the same second trench.

23. The method according to any one of claims 18-22, characterized in that, Before etching the second surface of the substrate to obtain the second trench, the method further includes: The substrate is thinned from its second surface.

24. A power amplifier chip, characterized in that, Includes the semiconductor device as described in any one of claims 1-11.

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