GaN device integrated with wire mesh type vapor chamber and application

Abstract

The invention belongs to the technical field of semiconductor devices, and discloses a GaN device integrated with a wire mesh type vapor chamber and application. Aiming at the heat dissipation bottleneck of a high-power-density GaN chip and the problem that the thermal resistance between the GaN chip and a vapor chamber in the existing discrete structure is reduced, the invention provides a GaN device integrated with a wire mesh type vapor chamber. The invention discloses a GaN device integrated with a metal wire mesh type vapor chamber. The GaN device sequentially comprises a GaN chip, an upper metal wire mesh, a lower metal wire mesh and a lower substrate from top to bottom. The upper metal wire mesh and the lower metal wire mesh are filled with working media, and the working media conduct gas-liquid phase change circulation in the vapor chamber to achieve heat dissipation. The GaN device integrated with the wire mesh type vapor chamber has the advantages of being high in heat conductivity coefficient, good in temperature uniformity, high in thermal load capacity and the like, and can be used for high-power-density microwave power devices.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to a GaN device and its application with an integrated metal mesh heat sink. Technical Background

[0002] With the continuous development of semiconductor technology, electronic devices are becoming smaller and more integrated. During operation, over half of the input power is dissipated as waste heat. For every 10°C increase in device temperature, lifespan decreases by 50%. GaN chips, with their wide bandgap, high breakdown field strength, and high electron mobility, have become core components in next-generation power electronics, radio frequency communications, and aerospace. However, limited by current heat dissipation capabilities, the actual output power of GaN chips can only reach 25% of the theoretical limit.

[0003] Currently, common heat dissipation methods include active and passive methods. Active cooling requires electrically driven components such as fans or pumps, and these components typically occupy more space. A vapor chamber, as a highly efficient and compact passive heat transfer element based on phase change heat transfer, utilizes the evaporation, condensation, and recirculation of the working fluid to achieve heat transfer. When the evaporation end is heated, the liquid working fluid impregnated in the wick vaporizes, rapidly absorbing a large amount of heat during the liquid-gas phase change. The generated vapor flows to the condensation end under the pressure difference. At the condensation end, the vapor releases heat through a cold source outside the shell and recondenses into a liquid. Subsequently, with the help of capillary force generated by the wick, the liquid working fluid flows back to the evaporation end, completing one heat transfer cycle. Vapor chambers have advantages such as high thermal conductivity, good temperature uniformity, and strong heat load capacity.

[0004] Currently, in practical applications of power devices, GaN chips and heat spreaders are typically used as discrete devices, mechanically connected or thermally coupled via conductive adhesive. This connection method presents significant interfacial thermal resistance issues. On one hand, the conductive adhesive itself has a lower thermal conductivity compared to the heat spreader and GaN chip; on the other hand, the contact thermal resistance between the adhesive layer and the material interface also hinders heat transfer, thereby reducing the heat dissipation efficiency of the GaN chip and affecting its performance and long-term reliability. Summary of the Invention

[0005] The technical problems to be solved by this invention are the heat dissipation bottleneck of high power density GaN chips and the reduction of thermal resistance between GaN chips and heat spreaders in existing discrete structures. This invention proposes a GaN device and its application with an integrated metal mesh heat spreader, which has the advantages of high thermal conductivity, good temperature uniformity and strong heat load capacity, and can be used in high power density microwave power devices.

[0006] To address the problems in the existing technology, the technical solution adopted by this invention is as follows:

[0007] A GaN device with an integrated metal mesh heat spreader comprises, from top to bottom, a GaN chip, an upper metal mesh, a lower metal mesh, and a lower substrate. The GaN chip is a GaN HEMT device, including a chip electrode, an AlGaN layer, a GaN layer, and a substrate. The upper and lower metal meshes have circular holes, and a fluid for self-circulating heat spreader is attached to the mesh surface. A connecting channel is provided on the surface where the lower and upper metal meshes contact, increasing capillary action and accelerating the circulation of the fluid between the substrate and the lower substrate. The lower substrate has a groove structure, the size and shape of which are the same as the upper and lower metal meshes, and the sum of the thicknesses of the upper and lower metal meshes does not exceed the depth of the groove structure. Support pillars are provided within the groove, passing sequentially through the lower and upper metal meshes. The GaN chip and the lower substrate are bonded together using a bonding process to form the GaN device.

[0008] As an improvement, the upper and lower metal wire meshes are made of stainless steel, brass, nickel, and aluminum, with a mesh count of 80-400 and thicknesses of 100-300μm and 300-1500μm, respectively.

[0009] As an improvement, the connecting channel is elongated, with a length of 1-6 mm, a width of 0.6-2 mm, and a height of 200-1500 μm.

[0010] As an improvement, the working fluid is water, methanol, ethanol or acetone, and the filling-to-liquid ratio is 20%-80%.

[0011] As an improvement, the substrate material is silicon, silicon carbide, or diamond, and the thickness is 10-500 μm.

[0012] As an improvement, the lower substrate has a groove-shaped structure, is made of copper or aluminum alloy, and has an overall height of 600-2000μm.

[0013] As an improvement, the support column is cylindrical with a diameter of 100-800μm and a height of 400-1800μm.

[0014] As an improvement, the sum of the thicknesses of the upper and lower wire meshes does not exceed the depth of the groove structure.

[0015] The above-mentioned GaN device with integrated metal mesh heat sink is used in the fabrication of high power density microwave power devices.

[0016] Invention principle:

[0017] This invention integrates a GaN chip with a vapor chamber. When the GaN chip is operating, the chip electrodes generate a large amount of heat. The working fluid immersed in the upper metal mesh vaporizes upon heating, rapidly absorbing a large amount of heat during the liquid-gas phase transition. The generated vapor working fluid flows to the lower substrate under the pressure difference. Subsequently, the vapor working fluid releases heat outward through the lower substrate and recondenses into liquid. The connecting channels increase capillary action, accelerating the circulation of the liquid between the upper and lower substrates. Then, with the help of the capillary force generated by the metal mesh, the liquid working fluid flows back to the upper metal mesh, completing one heat transfer cycle.

[0018] Beneficial effects:

[0019] Compared with existing technologies, this invention provides a GaN device with an integrated metal mesh heat sink. Through the two-phase heat dissipation mechanism of the heat sink, it significantly improves heat dissipation efficiency, enabling rapid removal of localized hotspot heat and achieving uniform temperature distribution. Compared with traditional heat dissipation solutions, it effectively solves the problem of interfacial thermal resistance between the GaN chip and the heat sink in discrete structures, greatly improving the performance and reliability of the GaN chip. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a GaN device with an integrated metal mesh heat sink according to the present invention, wherein 1-GaN chip, 2-upper metal mesh, 3-lower metal mesh, and 4-lower substrate.

[0021] Figure 2 This is a schematic diagram of the GaN chip structure of the present invention, wherein 5 is a chip electrode, 6 is an AlGaN layer, 7 is a GaN layer, and 8 is a substrate.

[0022] Figure 3 This is a schematic diagram of the upper and lower metal wire mesh structures of the present invention, wherein 9-circular hole, 10-flowing working fluid, and 11-connecting flow channel.

[0023] Figure 4 This is a schematic diagram of the substrate structure of the present invention, wherein 12 is a support column. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. Descriptions not covered in the specific embodiments of the present invention are techniques known in the art and can be implemented with reference to such techniques.

[0025] A GaN device with an integrated metal mesh heat spreader comprises, from top to bottom, a GaN chip 1, an upper metal mesh 2, a lower metal mesh 3, and a lower substrate 4; the GaN chip 1 is GaN... The HEMT device includes a chip electrode 5, an AlGaN layer 6, a GaN layer 7, and a substrate 8. The upper metal mesh 2 and the lower metal mesh 3 have circular holes 9, and a circulating working fluid 10 for self-circulating heat dissipation is attached to the mesh surface. A connecting channel 11 is provided on the surface where the lower metal mesh contacts the upper metal mesh 2. The connecting channel 11 increases capillary action and accelerates the circulation of the working fluid 10 between the substrate 8 and the lower substrate 4. The lower substrate 4 has a groove structure, the size and shape of which are the same as the upper metal mesh 2 and the lower metal mesh 3, and the sum of the thicknesses of the upper metal mesh 2 and the lower metal mesh 3 does not exceed the depth of the groove structure. Support pillars 12 are provided inside the groove, passing sequentially through the lower metal mesh 3 and the upper metal mesh 2. The GaN chip 1 and the lower substrate 4 are bonded together using a bonding process to form the GaN device.

[0026] As an improvement, the upper metal wire mesh 2 and the lower metal wire mesh 3 are made of stainless steel, brass, nickel, and aluminum, with a mesh count of 80-400 mesh and thicknesses of 100-300μm and 300-1500μm, respectively.

[0027] As an improvement, the connecting channel 11 is elongated, with a length of 1-6 mm, a width of 0.6-2 mm, and a height of 200-1500 μm.

[0028] As an improvement, the working fluid 10 is water, methanol, ethanol or acetone, and the filling-to-liquid ratio is 20%-80%.

[0029] As an improvement, the substrate 8 is made of silicon, silicon carbide or diamond, and has a thickness of 10-500 μm.

[0030] As an improvement, the lower substrate 4 is a groove-shaped structure, made of copper or aluminum alloy, with an overall height of 600-2000μm.

[0031] As an improvement, the support column is cylindrical with a diameter of 100-800μm and a height of 400-1800μm.

[0032] As an improvement, the sum of the thicknesses of the upper wire mesh 2 and the lower wire mesh 3 shall not exceed the depth of the groove structure.

[0033] Example 1

[0034] A GaN device with an integrated metal mesh heat sink, structure as follows: Figure 1As shown, from top to bottom, it includes a GaN chip 1, an upper metal mesh 2, a lower metal mesh 3, and a lower substrate 4. The GaN chip 1 and the lower substrate 4 are bonded together by a bonding process.

[0035] The GaN chip 1 is a GaN HEMT device, fabricated using semiconductor technology. Its structure is as follows: Figure 2 As shown, from top to bottom, it includes a chip electrode 5, an AlGaN layer 6, a GaN layer 7, and a substrate 8. The chip electrode 5 is the source, drain, and gate, and the chip electrode 5 is a heat source. The substrate material 8 is silicon carbide with a thickness of 450 μm.

[0036] Reference Figure 3 The upper metal mesh 2 has a thickness of 200 μm and the lower metal mesh 3 has a thickness of 1400 μm. Both are made of stainless steel with a mesh size of 100 mesh, serving as the liquid absorption core of the heat spreader. The upper and lower metal meshes 2 and 3 have circular holes 9, and a flowing medium 10 for self-circulating heat spreader is attached to their surfaces. The flowing medium 10 is water, which has a high latent heat of vaporization and a liquid-to-water ratio of 50%. A long, narrow connecting channel 11, 4 mm long, 2 mm wide, and 1200 μm high, is provided on the surface of the lower metal mesh that contacts the upper metal mesh 2. This connecting channel 11 connects the upper metal mesh 2 and the lower metal mesh 3, increasing capillary action and allowing the flowing medium 10 to circulate between the substrate 8 and the lower substrate 4.

[0037] Reference Figure 4 The lower substrate 4 has a groove-shaped structure made of copper, with an overall height of 2000 μm. The size and shape of the groove-shaped structure are the same as those of the upper metal mesh 2 and the lower metal mesh 3, and the sum of the thicknesses of the upper metal mesh 2 and the lower metal mesh 3 is equal to the depth of the groove-shaped structure. The groove contains a support pillar 12, which is cylindrical with a diameter of 400 μm and a height of 1600 μm. The diameter and position of the support pillar are the same as those of the circular hole 9. The purpose is to make the upper metal mesh 2, the lower metal mesh 3 and the lower substrate 4 form an integral whole, which can prevent the GaN chip 1 and the lower cover plate 4 from collapsing or deforming. In addition, the support pillar 12 not only improves the structural stability, but also has thermal conductivity, which can conduct heat locally, assisting the heat spreader to quickly balance the temperature distribution and reduce the occurrence of hot spots.

[0038] The working principle of the GaN device with an integrated metal mesh heat sink of the present invention is as follows: When the GaN chip is working, it generates a large amount of heat. The working fluid immersed in the upper and lower metal mesh is heated and vaporized. During the liquid-gas phase change process, it rapidly absorbs a large amount of heat. The generated vapor working fluid flows to the lower substrate under the pressure difference. Then, the vapor working fluid releases heat to the outside through the lower substrate and re-condenses into liquid. Subsequently, with the help of the capillary force generated by the metal mesh, the liquid working fluid flows back to the evaporation end, completing one heat transfer cycle.

[0039] In summary, the GaN device with an integrated metal mesh heat spreader of the present invention has advantages such as high thermal conductivity, good temperature uniformity, and strong heat load capacity, and can be used in high power density microwave power devices.

[0040] The above specific implementation methods and embodiments are specific support for the technical concept of GaN device with integrated metal mesh heat sink proposed in this invention, and should not be used to limit the scope of protection of this invention. Any equivalent changes or modifications made on the basis of this technical solution in accordance with the technical concept proposed in this invention shall still fall within the scope of protection of this invention.

Claims

1. A GaN device with an integrated metal mesh heat sink, characterized in that: The components, from top to bottom, include a GaN chip (1), an upper metal mesh (2), a lower metal mesh (3), and a lower substrate (4). The GaN chip (1) is a GaN HEMT device, comprising a chip electrode (5), an AlGaN layer (6), a GaN layer (7), and a substrate (8). The upper metal mesh (2) and the lower metal mesh (3) are provided with circular holes (9), and a fluid (10) for self-circulating heat dissipation is attached to the mesh surface. A connecting channel (11) is provided on the surface where the lower metal mesh contacts the upper metal mesh (2). The connecting channel (11) increases capillary action and accelerates the flow of the fluid (10) between the substrate (8) and the lower substrate (4). The circulation flow between them; the lower substrate (4) is a groove structure, the size and shape of the groove structure are the same as the upper metal mesh (2) and the lower metal mesh (3), and the sum of the thicknesses of the upper metal mesh (2) and the lower metal mesh (3) does not exceed the depth of the groove structure; a support column (12) is provided in the groove, and the support column (12) passes through the lower metal mesh (3) and the upper metal mesh (2) in sequence; the GaN chip (1) and the lower substrate (4) are bonded together to form a GaN device through a bonding process.

2. The GaN device with an integrated metal mesh heat sink according to claim 1, characterized in that: The upper metal wire mesh (2) and the lower metal wire mesh (3) are made of stainless steel, brass, nickel, and aluminum, with a mesh count of 80-400 and a thickness of 100-300 μm and 300-1500 μm, respectively.

3. The GaN device with an integrated metal mesh heat sink according to claim 1, characterized in that: The connecting channel (11) is elongated, with a length of 1-6 mm, a width of 0.6-2 mm, and a height of 200-1500 μm.

4. The GaN device with an integrated metal mesh heat sink according to claim 1, characterized in that: The working fluid (10) is water, methanol, ethanol or acetone, and the filling-to-liquid ratio is 20%-80%.

5. The GaN device with an integrated metal mesh heat sink according to claim 1, characterized in that: The substrate (8) is made of silicon, silicon carbide or diamond and has a thickness of 10-500 μm.

6. A GaN device with an integrated metal mesh heat sink according to claim 1, characterized in that: The lower substrate (4) is a groove-shaped structure made of copper or aluminum alloy, with an overall height of 600-2000μm.

7. A GaN device with an integrated metal mesh heat sink according to claim 1, characterized in that: The support column is cylindrical, with a diameter of 100-800μm and a height of 400-1800μm.

8. A GaN device with an integrated metal mesh heat sink according to claim 1, characterized in that: The sum of the thicknesses of the upper metal wire mesh (2) and the lower metal wire mesh (3) does not exceed the depth of the groove structure.

9. The application of GaN devices based on the integrated metal mesh heat sink according to any one of claims 1-8 in the fabrication of high power density microwave power devices.

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