A semiconductor composite material and its preparation method and device

Abstract

The present invention relates to a semiconductor composite material and a preparation method and device thereof, belonging to the field of semiconductor technology, and is used to solve at least one of the problems of low heat dissipation efficiency in the near-junction region of existing GaN devices and high interface thermal resistance caused by wafer bonding. The present invention designs a semiconductor composite material with a new structure, wherein the composite material connects a beveled substrate layer and a GaN material layer by wafer bonding, avoiding the introduction of a buffer layer structure, and an angle exists between the beveled substrate layer and the substrate material axis to form a beveled substrate layer with a turning angle. The beveled substrate layer with a turning angle and the GaN material layer are bonded by wafer, which can reduce the interface thermal resistance of the bonding interface after wafer bonding, and can effectively improve the heat dissipation efficiency of GaN high-power devices, thereby improving their output power density.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a semiconductor composite material and a preparation method and device thereof. Background Art

[0002] Due to the multi-dimensional requirements of GaN microwave power devices in terms of high thermal conductivity, high-quality self-supporting substrates, etc. In order to suppress the self-heating effect of GaN devices, improve the near-junction heat dissipation capability of GaN HEMT power devices, and thus increase their output power density, the method of directly epitaxially growing GaN heterojunction structures on SiC high thermal conductivity substrates is currently commonly used. This method requires the growth of a thicker buffer layer (μm level), and the presence of the buffer layer will reduce the heat dissipation efficiency of the near-junction region of the device. Wafer bonding technology can directly transfer the GaN epitaxial structure required for the preparation of the device to the target substrate with high thermal conductivity, avoiding the introduction of a buffer layer structure. However, the interface thermal resistance introduced by wafer bonding is relatively high, which hinders the further improvement of the device's heat dissipation capability. Summary of the invention

[0003] In view of the above analysis, the present invention aims to provide a semiconductor composite material and a preparation method and device thereof, so as to solve at least one of the problems of existing GaN devices, such as low heat dissipation efficiency in the near-junction region and high interface thermal resistance caused by wafer bonding.

[0004] In a first aspect, the present invention provides a semiconductor composite material, comprising a beveled substrate layer and a GaN material layer connected by wafer bonding, wherein the beveled substrate layer comprises a beveled surface, wherein the beveled surface is connected to the GaN material layer, and wherein the beveled surface is obtained by beveling, wherein an angle between the beveled direction and a plane perpendicular to the crystal direction of the beveled substrate layer material is α, wherein 0°<α≤90°.

[0005] Furthermore, the root mean square roughness of the surface where the chamfered surface is connected to the GaN material layer is less than 1 nm.

[0006] Furthermore, the material of the beveled substrate layer is one or more of SiC, diamond, AlN, and BN.

[0007] Furthermore, the GaN material layer is prepared on a semiconductor substrate.

[0008] Furthermore, the GaN material layer is a GaN epitaxial structure or a GaN HEMT device.

[0009] In a second aspect, the present invention provides a method for preparing a semiconductor composite material, comprising the following steps:

[0010] preparing a crystal ingot, beveling the crystal ingot, grinding and polishing the crystal ingot to obtain a beveled substrate layer having a beveled surface;

[0011] A GaN material layer is prepared, and the beveled surface of the beveled substrate layer is wafer-bonded with the GaN material layer to obtain the semiconductor composite material.

[0012] Furthermore, when the GaN material layer is a GaN epitaxial structure, the method further includes:

[0013] The GaN material is epitaxially grown on the semiconductor substrate, the beveled surface is bonded to the GaN material wafer, the semiconductor substrate is removed, and the GaN material is thinned to obtain the semiconductor composite material.

[0014] Furthermore, when the GaN material layer is a GaN HEMT device, the method further includes:

[0015] Preparing a GaN HEMT device on a semiconductor substrate, bonding the GaN HEMT device wafer to a temporary bonding substrate, and removing the semiconductor substrate to obtain a temporarily bonded GaN semiconductor device;

[0016] The temporarily bonded GaN semiconductor device is wafer-bonded to the beveled substrate layer, and the temporarily bonded substrate is released to obtain the semiconductor composite material.

[0017] In a third aspect, the present invention provides a device of the above-mentioned semiconductor composite material.

[0018] Furthermore, the device includes one or more of GaN high-frequency devices, high-power devices or high-temperature devices.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] (1) The present invention designs a semiconductor composite material with a new structure. The composite material connects a beveled substrate layer and a GaN material layer by wafer bonding, thereby avoiding the introduction of a buffer layer structure. The beveled substrate layer includes a beveled surface, which is connected to the GaN material layer. The beveled surface is obtained by bevel cutting, wherein an angle exists between the beveled direction and a plane perpendicular to the crystal direction of the beveled substrate layer material, thereby forming a beveled substrate layer with an angle. The beveled substrate layer with an angle is connected to the GaN material layer by wafer bonding. The GaN epitaxial structure can also be cut into a thin layer material with an angle, thereby reducing the interface thermal resistance of the bonding interface after wafer bonding, thereby effectively improving the heat dissipation efficiency of GaN high-power devices, and thereby improving their output power density.

[0021] (2) The present invention adopts wafer bonding technology to transfer the GaN epitaxial structure to the beveled substrate layer through thin film transfer technology, thereby obtaining GaN composite substrate materials and semiconductor devices. The semiconductor composite material of the present invention can be used to manufacture GaN high-frequency devices, high-power devices and high-temperature devices.

[0022] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0024] Figure 1 A schematic diagram of the structure of a semiconductor composite material of the present invention;

[0025] Figure 2 A process flow chart for producing a semiconductor composite material according to the present invention;

[0026] Figure 3 A process flow chart for producing a semiconductor composite material according to the present invention;

[0027] Figure 4 The present invention is a schematic diagram of a process of beveling a beveled substrate layer at a bevel angle of 90° to form a beveled substrate layer with a 90° turning angle.

[0028] Reference numerals:

[0029] 1-beveled substrate layer, 11-ingot, 2-GaN material layer, 3-semiconductor substrate, 4-GaN epitaxial structure, 5-GaN HEMT device, 6-temporary bonding substrate. DETAILED DESCRIPTION

[0030] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0031] A specific embodiment of the present invention, as Figure 1As shown, a semiconductor composite material is disclosed, comprising a beveled substrate layer 1 and a GaN material layer 2 connected by wafer bonding, wherein the beveled substrate layer 1 comprises a beveled surface, wherein the beveled surface is connected to the GaN material layer 2, and wherein the beveled surface is obtained by beveling, wherein an angle between the beveled direction and a plane perpendicular to the crystal direction of the beveled substrate layer material is α, wherein 0°<α≤90°, for example, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, or other specific angles, preferably, 45°≤α≤90°, more preferably, α=90°.

[0032] Compared with the prior art, the present invention designs a semiconductor composite material with a new structure. The composite material connects the beveled substrate layer 1 and the GaN material layer 2 by wafer bonding, avoiding the introduction of a buffer layer structure. The bevel direction of the beveled substrate layer 1 and the plane perpendicular to the crystal direction of the beveled substrate layer material have an angle, thereby forming a beveled substrate layer 1 with an angle. The beveled substrate layer 1 with an angle is connected to the GaN material layer 2 by wafer bonding, which can reduce the interfacial thermal resistance of the bonding interface after wafer bonding. The semiconductor composite material of the present invention can effectively improve the heat dissipation efficiency of GaN high-power devices, thereby improving the output power density of the device.

[0033] The inventors have found through experiments that when the beveled substrate layer 1 with different bevel angles (α) is connected to the GaN material layer 2, the atomic arrangement structure is different, resulting in different coupling efficiencies of interface thermal phonon transmission, which in turn affects the interface thermal resistance.

[0034] If necessary, Figure 4 As shown, the corner structure formed by beveling the substrate layer is explained as an example. The crystal orientation of the substrate layer material is (0001), and the angle between the beveling direction and the plane perpendicular to the crystal orientation of the beveling substrate layer material is α=90°. After beveling, a beveled surface with a 90° angle is formed. The beveled surface is connected to the GaN material layer through wafer bonding, which can reduce the interface thermal resistance after wafer bonding.

[0035] In a specific embodiment, the root mean square roughness of the surface where the beveled surface is connected to the GaN material layer 2 is less than 1 nm, for example, 0.9 nm, 0.8 nm, 0.7 nm, 0.6 nm, 0.5 nm, 0.4 nm, 0.3 nm, 0.2 nm, 0.1 nm. The above root mean square roughness can meet the requirements of wafer bonding, so that the beveled substrate layer 1 and the GaN material layer 2 are connected.

[0036] In a specific embodiment, the material of the beveled substrate layer 1 is one or more of SiC, diamond, AlN, and BN.

[0037] In a specific embodiment, the thickness of the beveled substrate layer 1 is 1-1000μm, for example, 1μm, 50μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, 550μm, 600μm, 650μm, 700μm, 750μm, 800μm, 850μm, 900μm, 950μm, 1000μm.

[0038] In a specific implementation, the GaN material layer 2 is prepared on a semiconductor substrate 3 .

[0039] In a preferred embodiment, the material of the semiconductor substrate 3 is one or more of Si, SiC, sapphire, and GaN.

[0040] In a specific embodiment, Figure 2 and 3 As shown, the GaN material layer 2 is a GaN epitaxial structure 4 or a GaN HEMT device 5 .

[0041] Specifically, the GaN epitaxial structure 4 is a GaN bulk material layer or a GaN-based heterostructure.

[0042] It should be noted that the GaN bulk material layer in the present invention is made of pure GaN material, and the GaN-based heterostructure is prepared by an existing method.

[0043] A specific embodiment of the present invention discloses a method for preparing the above-mentioned semiconductor composite material, comprising the following steps:

[0044] preparing a crystal ingot, beveling the crystal ingot, grinding and polishing the crystal ingot to obtain a beveled substrate layer having a beveled surface;

[0045] A GaN material layer is prepared, and the beveled surface of the beveled substrate layer is wafer-bonded with the GaN material layer to obtain the semiconductor composite material.

[0046] In a specific embodiment, Figure 2 As shown, when the GaN material layer 2 is a GaN epitaxial structure 4, the method for preparing the semiconductor composite material comprises the following steps:

[0047] (1) preparing a crystal ingot 11 from a single crystal material, beveling the crystal ingot 11, wherein the angle between the beveling direction and a plane perpendicular to the crystal direction of the single crystal material is α, wherein 0°<α≤90°, to obtain a beveling wafer, and grinding and polishing the beveling wafer to obtain a beveling substrate layer 1;

[0048] (2) epitaxially growing GaN material on the semiconductor substrate 3, and wafer bonding the beveled substrate layer 1 and the GaN material to obtain a composite structure;

[0049] (3) Removing the semiconductor substrate 3 on the composite structure, thinning the GaN material, and obtaining the semiconductor composite material.

[0050] It should be noted that the beveling in the present invention adopts a conventional method, which can be one of plasma cutting, laser cutting or diamond wire cutting.

[0051] In a specific embodiment, in step (2), the wafer bonding parameters are as follows: temperature <150°C, vacuum degree less than 1e -6 Pa, the pressure is 500-10000N, for example, the pressure is 500N, 1000N, 2000N, 3000N, 4000N, 5000N, 6000N, 7000N, 8000N, 9000N, and 10000N.

[0052] In a specific embodiment, in step (3), laser lift-off or mechanical grinding is used to remove the semiconductor substrate 3 on the composite structure.

[0053] In a specific embodiment, in step (3), the GaN material is thinned by chemical mechanical polishing or dry etching, and the thickness of the removed GaN material is 0.01 to 3 μm, for example, 0.01 μm, 0.03 μm, 0.05 μm, 0.07 μm, 0.09 μm, 0.1 μm, 0.3 μm, 0.5 μm, 0.7 μm, 0.9 μm, 1.1 μm, 1.3 μm, 1.5 μm, 1.7 μm, 1.9 μm, 2.1 μm, 2.3 μm, 2.5 μm, 2.7 μm, 2.9 μm, and 3.0 μm.

[0054] In a specific embodiment, step (3) further includes providing an electrode on the semiconductor composite material to obtain a semiconductor device.

[0055] In a preferred embodiment, the CaN epitaxial structure 4 may also have a beveled surface like the beveled substrate layer 1 , and the beveling method and angle are the same as those of the beveled substrate layer 1 .

[0056] In a specific embodiment, Figure 3 As shown, when the GaN material layer 2 is a GaN HEMT device 5, the method for preparing the composite material comprises the following steps:

[0057] (a) preparing a crystal ingot 11 from a single crystal material, beveling the crystal ingot 11, wherein the angle between the beveling direction and a plane perpendicular to the crystal direction of the single crystal material is α, wherein 0°<α≤90°, to obtain a beveling wafer, and grinding and polishing the beveling wafer to obtain a beveling substrate layer 1;

[0058] (b) preparing a GaN HEMT device 5 on a semiconductor substrate 3, wafer bonding the GaN HEMT device 5 to a temporary bonding substrate 6, and removing the semiconductor substrate 3 to obtain a temporarily bonded GaN semiconductor device;

[0059] (c) Wafer bonding the temporarily bonded GaN semiconductor device to the beveled substrate layer 1, and releasing the temporarily bonded substrate 6 to obtain the semiconductor composite material.

[0060] In a specific embodiment, in step (b), the temporary bonding substrate 6 is made of silicon substrate material.

[0061] Specifically, in step (b), the parameters for wafer bonding are as follows: the temperature is room temperature, and the vacuum degree is less than 1e -6 Pa, the pressure is 500-10000N, for example, the pressure is 500N, 1000N, 2000N, 3000N, 4000N, 5000N, 6000N, 7000N, 8000N, 9000N, and 10000N.

[0062] In a specific embodiment, in step (b), the semiconductor substrate 3 is removed by laser lift-off or mechanical grinding.

[0063] In a specific embodiment, preparing the GaN HEMT device 5 on the semiconductor substrate 3 specifically includes: epitaxially growing a GaN material on the semiconductor substrate 3 , and providing an electrode on the GaN material to obtain the GaN HEMT device 5 .

[0064] In a specific embodiment, step (b) further includes removing the semiconductor substrate 3 and then using chemical mechanical polishing, dry etching or ion beam polishing to reduce the surface roughness of the GaN material to achieve the surface roughness required for wafer bonding.

[0065] Specifically, the root mean square roughness of the GaN material surface is less than 1 nm.

[0066] In a specific embodiment, in step (c), the parameters of wafer bonding are as follows: the temperature is room temperature, the vacuum degree is less than 1e -6Pa, the pressure is 500-10000N, for example, the pressure is 500N, 1000N, 2000N, 3000N, 4000N, 5000N, 6000N, 7000N, 8000N, 9000N, and 10000N.

[0067] Specifically, in step (c), the temporary bonding substrate 6 is removed by wet etching or dry etching.

[0068] Specifically, when the bevel-cut substrate material is SiC, the interface thermal resistance is 6 to 19 m 2 KGW -1 , for example, 6m 2 KGW -1 、7m 2 K W -1 、8m 2 K W -1 、9m 2 K W -1 、10m 2 K W -1 、11m 2 K W -1 、12m 2 K W -1 、13m 2 K W -1 、14m 2 K W -1 、15m 2 K W -1 、16m 2 K W -1 、17m 2 K W -1 、18m 2 K W -1 、19m 2 K W -1 , the thermal resistance of the semiconductor device is 15-22℃ / W, for example, 15℃ / W, 16℃ / W, 17℃ / W, 18℃ / W, 19℃ / W, 20℃ / W, 21℃ / W, and 22℃ / W.

[0069] Specifically, when the bevel-cut substrate material is diamond, the interface thermal resistance is 3 to 13 m 2 KGW -1 , for example, 3m 2 K W -1 、4m 2 K W -1 、5m 2 K W -1 、6m 2K W -1 、7m 2 K W -1 、8m 2 K W -1 、9m 2 K W -1 、10m 2 K W -1 、11m 2 K W -1 、12m 2 K W -1 、13m 2 K W -1 , the thermal resistance of the semiconductor device is 7 to 15°C / W, for example, 7°C / W, 8°C / W, 9°C / W, 10°C / W, 11°C / W, 12°C / W, 13°C / W, 14°C / W, and 15°C / W.

[0070] The semiconductor composite material described in the present invention solves the problem that a thicker buffer layer needs to be grown for epitaxial growth of high-quality GaN material on the semiconductor substrate 3 through wafer bonding technology, which is beneficial for the Joule heat in the channel region of the device to be quickly dissipated from the semiconductor substrate 3 with high thermal conductivity, thereby reducing the self-heating effect of the device and improving the output power density of the device. On the other hand, wafer bonding of the GaN epitaxial structure to the beveled substrate layer can effectively reduce the interfacial thermal resistance of the wafer bonding interface and effectively improve the heat dissipation effect of the semiconductor composite material. The method of the present invention can manufacture GaN high-power devices, high-frequency devices and high-temperature devices.

[0071] The technical solution of the present invention is further explained below in conjunction with specific embodiments.

[0072] Example 1

[0073] like Figure 1 and 2 As shown, a semiconductor composite material includes a beveled substrate layer 1 and a GaN material layer 2 connected by wafer bonding, wherein the beveled substrate layer 1 includes a beveled surface, the beveled surface is connected to the GaN material layer 2, and the beveled surface is obtained by plasma cutting, wherein the angle between the beveled direction and the plane perpendicular to the crystal direction of the beveled substrate layer material is 45°.

[0074] Among them, the root mean square roughness of the surface where the beveled surface is connected to the GaN material layer 2 is less than 1nm; the material of the beveled substrate layer 1 is SiC, the thickness of the beveled substrate layer 1 is 400μm, and the GaN material layer 2 is a GaN epitaxial structure 4.

[0075] The method for preparing the semiconductor composite material of this embodiment comprises the following steps:

[0076] (1) preparing a SiC ingot 11 from a SiC single crystal material, beveling the SiC ingot 11, wherein the angle between the beveling direction and a plane perpendicular to the crystal direction of the SiC single crystal material is 45°, to obtain a beveling wafer, grinding and polishing the beveling wafer to make the root mean square roughness of the beveling wafer surface less than 1 nm, to obtain a beveling substrate layer 1;

[0077] (2) epitaxially growing GaN material on a sapphire substrate, and wafer bonding the beveled surface of the beveled substrate layer 1 to the GaN material. The wafer bonding parameters are as follows: temperature <150°C, vacuum degree less than 1e -6 Pa, the pressure is 500N, and the composite structure is obtained;

[0078] (3) The sapphire substrate on the composite structure is removed by laser stripping, and the GaN material is thinned to a thickness of 0.1 μm, thereby obtaining the semiconductor composite material.

[0079] Electrodes are arranged on the semiconductor composite material prepared in this embodiment to obtain a semiconductor device.

[0080] Example 2

[0081] like Figure 1 and 2 As shown, a semiconductor composite material includes a beveled substrate layer 1 and a GaN material layer 2 connected by wafer bonding, wherein the beveled substrate layer 1 includes a beveled surface, wherein the beveled surface is connected to the GaN material layer 2, and wherein the beveled surface is obtained by plasma cutting beveling, wherein the angle between the beveled direction and the plane perpendicular to the crystal direction of the beveled substrate layer material is 90°.

[0082] Among them, the root mean square roughness of the surface where the beveled surface is connected to the GaN material layer 2 is less than 1nm; the material of the beveled substrate layer 1 is SiC, the thickness of the beveled substrate layer 1 is 400μm, and the GaN material layer 2 is a GaN epitaxial structure 4.

[0083] The method for preparing the semiconductor composite material of this embodiment comprises the following steps:

[0084] (1) preparing a crystal ingot 11 from a single crystal material, beveling the crystal ingot 11, wherein the angle between the beveling direction and a plane perpendicular to the crystal direction of the single crystal material is 90°, to obtain a beveling wafer, grinding and polishing the beveling wafer to make the root mean square roughness of the surface of the beveling wafer less than 1 nm, to obtain a beveling substrate layer 1;

[0085] (2) epitaxially growing GaN material on the Si semiconductor substrate 3, and performing wafer bonding between the beveled surface of the beveled substrate layer 1 and the GaN material. The wafer bonding parameters are as follows: temperature <150°C, vacuum degree less than 1e -6 Pa, the pressure is 1000N, and the composite structure is obtained;

[0086] (3) Chemical mechanical polishing is used to remove the Si semiconductor substrate 3 on the composite structure, and the GaN material is thinned to a thickness of 1 μm, thereby obtaining the semiconductor composite material.

[0087] Electrodes are arranged on the semiconductor composite material prepared in this embodiment to obtain a semiconductor device.

[0088] Example 3

[0089] like Figure 1 and 3 As shown, a semiconductor composite material includes a beveled substrate layer 1 and a GaN material layer 2 connected by wafer bonding, wherein the beveled substrate layer 1 includes a beveled surface, wherein the beveled surface is connected to the GaN material layer 2, and wherein the beveled surface is obtained by plasma cutting beveling, wherein the angle between the beveled direction and the plane perpendicular to the crystal direction of the beveled substrate layer material is 90°.

[0090] Among them, the root mean square roughness of the surface where the beveled surface is connected to the GaN material layer 2 is less than 1 nm; the material of the beveled substrate layer 1 is SiC, the thickness of the beveled substrate layer 1 is 400 μm, and the GaN material layer 2 is a GaN HEMT device 5.

[0091] The method for preparing the semiconductor composite material of this embodiment comprises the following steps:

[0092] (a) preparing a crystal ingot 11 from a single crystal material, beveling the crystal ingot 11, wherein the angle between the beveling direction and a plane perpendicular to the crystal direction of the single crystal material is 90°, to obtain a beveling wafer, grinding and polishing the beveling wafer to make the root mean square roughness of the beveling wafer surface less than 1 nm, to obtain a beveling substrate layer 1;

[0093] (b) epitaxially growing GaN material on a sapphire semiconductor substrate 3, setting electrodes on the GaN material to obtain a GaN HEMT device 5, and bonding the GaN HEMT device 5 wafer to a temporary bonding substrate 6. The wafer bonding parameters are as follows: the temperature is room temperature, the vacuum degree is less than 1e -6Pa, the pressure is 500N, the material of the temporary bonding substrate 6 is a Si substrate, laser stripping is used to remove the sapphire semiconductor substrate 3, and chemical mechanical polishing and dry etching are combined to reduce the surface roughness of the GaN material, so that the root mean square roughness is less than 1nm, to obtain a temporarily bonded GaN semiconductor device;

[0094] (c) Wafer bonding the temporarily bonded GaN semiconductor device to the beveled surface of the beveled substrate layer 1, the wafer bonding parameters are as follows: the temperature is room temperature, the vacuum degree is less than 1e -6 Pa, the pressure is 500N, and wet etching is used to release the temporary bonded substrate 6 to obtain the semiconductor composite material, namely the GaN semiconductor device.

[0095] Example 4

[0096] like Figure 1 and 3 As shown, a semiconductor composite material includes a beveled substrate layer 1 and a GaN material layer 2 connected by wafer bonding, wherein the beveled substrate layer 1 includes a beveled surface, wherein the beveled surface is connected to the GaN material layer 2, and wherein the beveled surface is obtained by plasma cutting beveling, wherein the angle between the beveled direction and the plane perpendicular to the crystal direction of the beveled substrate layer material is 90°.

[0097] The root mean square roughness of the surface where the beveled surface is connected to the GaN material layer 2 is less than 1 nm; the material of the beveled substrate layer 1 is diamond, the thickness of the beveled substrate layer 1 is 400 μm, and the GaN material layer 2 is a GaN HEMT device 5.

[0098] The method for preparing the semiconductor composite material of this embodiment comprises the following steps:

[0099] (a) preparing a crystal ingot 11 from a single crystal material, beveling the crystal ingot 11, wherein the angle between the beveling direction and a plane perpendicular to the crystal direction of the single crystal material is 90°, to obtain a beveling wafer, grinding and polishing the beveling wafer to make the root mean square roughness of the beveling wafer surface less than 1 nm, to obtain a beveling substrate layer 1;

[0100] (b) epitaxially growing GaN material on SiC semiconductor substrate 3, setting electrodes on GaN material to obtain GaN HEMT device 5, and wafer bonding the GaN HEMT device 5 to temporary bonding substrate 6. The wafer bonding parameters are as follows: the temperature is room temperature, the vacuum degree is less than 1e -6Pa, the pressure is 10000N, the material of the temporary bonding substrate 6 is a Si substrate, chemical mechanical polishing and dry etching are used to remove the SiC semiconductor substrate 3, and chemical mechanical polishing is used to reduce the surface roughness of the GaN material to make the root mean square roughness less than 1nm, so as to obtain a temporarily bonded GaN semiconductor device;

[0101] (c) Wafer bonding the temporarily bonded GaN semiconductor device to the beveled surface of the beveled substrate layer 1, the wafer bonding parameters are as follows: the temperature is room temperature, the vacuum degree is less than 1e -6 Pa, the pressure is 10000N, and the temporary bonded substrate 6 is released by dry etching to obtain the semiconductor composite material, namely the GaN semiconductor device.

[0102] Example 5

[0103] The semiconductor composite material and semiconductor device of this comparative example are the same as those of Example 1, except that the angle between the bevel direction of the bevel substrate layer 1 and the plane perpendicular to the crystal direction of the bevel substrate layer material is 10°.

[0104] Example 6

[0105] The semiconductor composite material and semiconductor device of this comparative example are the same as those of Example 4, except that the angle between the bevel direction of the bevel substrate layer 1 and the plane perpendicular to the crystal direction of the bevel substrate layer material is 10°.

[0106] Comparative Example 1

[0107] The semiconductor composite material of this comparative example is the same as that of Example 1, except that α is 0° (i.e., no bevel cutting is performed, and the bevel cutting surface is a planar structure without a corner structure). The semiconductor composite material of this comparative example is made into a semiconductor device according to the method of Example 1.

[0108] Comparative Example 2

[0109] The semiconductor composite material of this comparative example is the same as that of Example 4, except that α is 0° (ie, no bevel cutting is performed, and the bevel cutting surface is a planar structure without a corner structure).

[0110] Test Example 1

[0111] (1) The thermal resistance of the semiconductor devices prepared in Examples 1-6 and Comparative Examples 1-2 under GaN conditions of 5-10 W / mm was measured using infrared microscopy technology. The results are shown in Table 1.

[0112] (2) The interfacial thermal resistance between the substrate layer 1 and the GaN material layer 2 in Examples 1-6 and Comparative Examples 1-2 was tested respectively, using a transient thermal reflection method.

[0113] Table 1

[0114]

[0115] From the comparison of Examples 1-2 and 5 with Comparative Example 1, it can be seen that for a specific beveled substrate layer material, when the bevel angle gradually increases, the interface thermal resistance gradually decreases. For a substrate that is not beveled, the interface thermal resistance is relatively large. When α=90°, the interface thermal resistance can be reduced by at least half. The preferred embodiment of the present invention is 45°≤α≤90°C.

[0116] Since different beveled substrate materials will affect the interface thermal resistance, the interface thermal resistance of different beveled substrate materials with the same α is slightly different, and the interface thermal resistance is directly related to the overall junction temperature of the device. In addition, as the interface thermal resistance decreases, the thermal resistance of the device also decreases.

[0117] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A semiconductor composite material, characterized in that: It includes a beveled substrate layer and a GaN material layer connected by wafer bonding, wherein the beveled substrate layer includes a beveled surface, wherein the beveled surface is connected to the GaN material layer, and wherein the beveled surface is obtained by beveling, wherein the angle between the beveled direction and a plane perpendicular to the crystal direction of the beveled substrate layer material is α, wherein 0°<α≤90°, and the substrate material is a single crystal material.

2. A semiconductor composite material according to claim 1, characterized in that: The root mean square roughness of the surface where the chamfered surface is connected to the GaN material layer is less than 1 nm.

3. The semiconductor composite material according to claim 1, characterized in that: The material of the beveled substrate layer is one or more of SiC, diamond, AlN and BN.

4. A semiconductor composite material according to any one of claims 1 to 3, characterized in that: The GaN material layer is prepared on a semiconductor substrate.

5. A semiconductor composite material according to any one of claims 1 to 3, characterized in that: The GaN material layer is a GaN epitaxial structure or a GaN HEMT device.

6. A method for preparing the semiconductor composite material according to any one of claims 1 to 5, characterized in that: The steps include: preparing a crystal ingot, beveling the crystal ingot, grinding and polishing the crystal ingot to obtain a beveled substrate layer having a beveled surface; A GaN material layer is prepared, and the beveled surface of the beveled substrate layer is wafer-bonded with the GaN material layer to obtain the semiconductor composite material.

7. The preparation method according to claim 6, characterized in that: When the GaN material layer is a GaN epitaxial structure, the method further comprises: The GaN material is epitaxially grown on the semiconductor substrate, the beveled surface is bonded to the GaN material wafer, the semiconductor substrate is removed, and the GaN material is thinned to obtain the semiconductor composite material.

8. The preparation method according to claim 6, characterized in that: When the GaN material layer is a GaN HEMT device, the method further comprises: Preparing a GaN HEMT device on a semiconductor substrate, bonding the GaN HEMT device wafer to a temporary bonding substrate, and removing the semiconductor substrate to obtain a temporarily bonded GaN semiconductor device; The temporarily bonded GaN semiconductor device is wafer-bonded to the beveled substrate layer, and the temporarily bonded substrate is released to obtain the semiconductor composite material.

9. A device comprising the semiconductor composite material according to any one of claims 1 to 5.

10. The device according to claim 9, characterized in that The device includes one or more of GaN high-frequency devices, high-power devices or high-temperature devices.

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