JP2022177017A - Method for producing semiconductor substrate structure and semiconductor substrate structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor substrate structure that can be freed from restrictions on materials, and can achieve cost reduction and desired physical properties, and a power semiconductor device having the semiconductor substrate structure.

SOLUTION: A semiconductor substrate structure has a substrate (10, 10SB) and a silicon carbide epitaxial growth layer 12 bonded to the substrate (10, 10SB). The substrate (10, 10SB) and the silicon carbide epitaxial growth layer 12 are bonded by normal-temperature bonding or diffusion bonding. The substrate (10, 10SB) has sintered silicon carbide, carbon, or graphite. The bonding may be performed through an interfacial bonding layer 14. The interfacial bonding layer 14 may have a metal layer or amorphous SiC.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present embodiment relates to a method for manufacturing a semiconductor substrate structure and a semiconductor substrate structure.

In recent years, compared to Si semiconductors and GaAs semiconductors, the bandgap energy is wider and it has high electric field withstand voltage performance. Silicon carbide (SiC: silicon carbide) semiconductors that can be realized are attracting attention. SiC is attracting attention also from the point of view of environmental protection, since it can reduce the generation of carbon dioxide gas (CO ₂ ) due to its low power consumption performance.

Recently, SiC devices have been applied to many application fields such as air conditioners (air conditioners), photovoltaic power generation systems, automobile systems, and train/vehicle systems.

As a method for forming a SiC wafer, for example, a method of forming a SiC epitaxial growth layer by a chemical vapor deposition (CVD) method on a SiC single crystal substrate by a sublimation method, or a method of forming a SiC epitaxial growth layer on a SiC CVD polycrystalline substrate. On the other hand, there is a method of attaching a SiC single crystal substrate by a sublimation method and further forming a SiC epitaxial growth layer on the SiC single crystal substrate by a CVD method.

Japanese Patent No. 6206786

Hitherto, in semiconductor devices using SiC, an epitaxial growth layer was formed on a substrate, so it was necessary to fabricate them sequentially.

Since the SiC epitaxially grown layer inherits the crystal structure of the underlying SiC single crystal substrate, a SiC single crystal substrate with good crystal quality is desirable. As a result, there is a need for high-quality substrates such as single-crystal substrates that have characteristics required for substrates for epitaxial growth, such as similar lattice constants and thermal expansion coefficients.

The present embodiment provides a method for manufacturing a semiconductor substrate structure and a semiconductor substrate structure that can eliminate restrictions on materials, reduce costs, and obtain desired physical properties.

According to one aspect of the present embodiment, a substrate and an epitaxial growth layer are prepared, and the respective surfaces of the substrate and the epitaxial growth layer are etched in a vacuum to form atoms having bonds on the respective surfaces. A method is provided for fabricating a semiconductor substrate structure comprising exposing and room temperature bonding the substrate and the epitaxially grown layer in vacuum.

According to another aspect of the present embodiment, a substrate and an epitaxial growth layer are prepared, surfaces of the substrate and the epitaxial growth layer are brought into close contact with each other, and the substrate and the epitaxial growth layer are brought into close contact with each other. are heated and pressurized in a controlled atmosphere in vacuum or inert gas to diffusion bond.

According to the present embodiment, it is possible to provide a method for manufacturing a semiconductor substrate structure and a semiconductor substrate structure that can eliminate restrictions on materials, reduce costs, and obtain desired physical properties.

(a) Schematic cross-sectional structural view of a semiconductor substrate structure according to an embodiment to which the present technology is applied, (b) Another schematic cross-sectional structure of a semiconductor substrate structure according to an embodiment to which the present technology is applied figure. (a) Still another schematic cross-sectional structural view of a semiconductor substrate structure according to an embodiment to which the present technology is applied, (b) Still another semiconductor substrate structure according to an embodiment to which the present technology is applied A typical cross-sectional structure figure. (a) Still another schematic cross-sectional structural view of a semiconductor substrate structure according to an embodiment to which the present technology is applied, (b) Still another semiconductor substrate structure according to an embodiment to which the present technology is applied A typical cross-sectional structure figure. (a) Explanatory drawing of the manufacturing process of the semiconductor substrate structure according to one embodiment to which the present technology is applied, (b) Explanatory drawing of the manufacturing process of the semiconductor substrate structure according to one embodiment to which the present technology is applied. Description of room temperature bonding applicable to a method for manufacturing a semiconductor substrate structure according to an embodiment to which the present technology is applied, comprising (a) a schematic diagram of a first substrate covered with contaminants, (b) Schematic diagram of the second substrate covered with contaminants, (c) schematic diagram of the etching process of the surface of the first substrate covered with contaminants, (d) the surface of the second substrate covered with contaminants. Schematic diagram of the etching process, (e) schematic diagram of the process of forming a bond between the cleaned active surface of the first substrate and the cleaned active surface of the second substrate, (f) the active surface of the first substrate and FIG. 4 is a schematic diagram of a process in which the active surface of the second substrate is bonded at room temperature; FIG. 4 is an explanatory diagram of a diffusion bonding method applicable to a method of manufacturing a semiconductor substrate structure according to an embodiment to which the present technology is applied; Description of a diffusion bonding method applicable to a method for manufacturing a semiconductor substrate structure according to an embodiment to which the present technology is applied, including (a) a schematic diagram of a state in which a bonding material is arranged on a substrate, (b) In the state of FIG. 7(a), a pressure/heating step is performed to form a diffusion bonding with voids. Schematic diagram of the formed state. Description of a solid phase diffusion bonding method applicable to a method for manufacturing a semiconductor substrate structure according to an embodiment to which the present technology is applied, in which (a) a bonding material is arranged on a substrate via an insert metal layer Schematic diagram of the state, (b) schematic diagram of the state in which the pressure and heating process is performed in the state of FIG. , and a schematic diagram of a state in which solid-phase diffusion bonding is formed. BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing of the crystal state of ceramics, Comprising: (a) Schematic drawing of a polycrystal, (b) Schematic drawing of an amorphous amorphous solid. 1 is a schematic diagram of an apparatus for manufacturing a polycrystalline body (SiC sintered body) of a semiconductor substrate structure according to an embodiment to which the present technology is applied; FIG. 1 is a schematic cross-sectional structural view of a semiconductor substrate structure according to an embodiment to which the present technology is applied; FIG. 1 is a schematic bird's-eye view configuration diagram of a graphite substrate applicable to a semiconductor substrate structure according to an embodiment to which the present technology is applied; FIG. 1 shows an example of a graphite substrate applicable to a semiconductor substrate structure according to an embodiment to which the present technology is applied, including (a) a schematic bird's-eye view configuration diagram of an XY-oriented graphite substrate, and (b) an XZ-oriented graphite substrate. Schematic bird's-eye view configuration diagram. 1 is a schematic cross-sectional structural diagram of a Schottky barrier diode manufactured using a semiconductor substrate structure according to an embodiment to which the present technology is applied; FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional structural diagram of a trench gate type MOSFET manufactured using a semiconductor substrate structure according to one embodiment to which the present technology is applied; 1 is a schematic cross-sectional structural view of a planar gate type MOSFET manufactured using a semiconductor substrate structure according to an embodiment to which the present technology is applied; FIG. (a) A schematic bird's-eye view configuration diagram of a semiconductor substrate structure (wafer) according to an embodiment to which the present technology is applied, (b) A semiconductor substrate structure (wafer) according to an embodiment to which the present technology is applied Schematic bird's-eye view configuration diagram (example provided with a bonding interface layer). (a) Schematic bird's-eye view configuration diagram of a unit cell of 4H-SiC crystal applicable to the SiC epitaxial substrate of the semiconductor substrate structure according to one embodiment to which the present technology is applied, (b) Two layers of 4H-SiC crystal (c) A schematic diagram of the four-layer portion of the 4H—SiC crystal. FIG. 18(a) is a schematic configuration diagram of the unit cell of the 4H—SiC crystal shown in FIG. 18(a) viewed from directly above the (0001) plane.

Next, this embodiment will be described with reference to the drawings. In the description of the drawings described below, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness of each component and the planar dimensions, etc., differs from the actual one. Therefore, specific thicknesses and dimensions should be determined with reference to the following description. In addition, it goes without saying that there are portions with different dimensional relationships and ratios between the drawings.

Moreover, the embodiments shown below are intended to exemplify apparatuses and methods for embodying technical ideas, and do not specify the material, shape, structure, arrangement, etc. of each component. Various modifications can be made to this embodiment within the scope of the claims.

A schematic cross-sectional structure of a semiconductor substrate structure according to an embodiment to which the present technology is applied is shown as shown in FIG. 1A, and another schematic cross-sectional structure of the semiconductor substrate structure is shown in FIG. b) is represented as shown.

A semiconductor substrate structure 1 according to an embodiment to which the present technology is applied includes a substrate (SUB) 10 and an epitaxial growth layer 12 bonded to the substrate 10, as shown in FIG. and the epitaxial growth layer 12 are bonded by room temperature bonding. Here, room temperature bonding includes at least one or a plurality of types selected from surface activated bonding, plasma activated bonding, and atomic diffusion bonding.

Also, the substrate 10 and the epitaxial growth layer 12 may be bonded by diffusion bonding. 1A and 1B show an example in which the epitaxial growth layer 12 is a SiC epitaxial growth layer (SiC-epi). The example of FIG. 1B shows an example in which the substrate 10 is a SiC sintered body.

The epitaxial growth layer 12 may comprise at least one or more selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors.

Also, the epitaxial growth layer 12 may comprise at least one or more selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

Also, the substrate 10 may comprise at least one or a plurality of materials selected from the group consisting of sintered bodies _, BN, _AlN , _Al2O3 , _Ga2O3 , diamond, carbon, and graphite. Here, the sintered body may include at least one type or a plurality of types of sintered bodies selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors. Also, the sintered body may comprise at least one or a plurality of sintered bodies selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

Still another schematic cross-sectional structure of a semiconductor substrate structure according to an embodiment to which the present technology is applied is represented as shown in FIG. , is represented as shown in FIG. 2A and 2B show an example in which the epitaxial growth layer 12 is a SiC epitaxial growth layer (SiC-epi). Moreover, an example in which the substrate 10 is a SiC sintered body 10SB is shown. Furthermore, in the example of FIG. 2A, the SiC sintered body 10SB is arranged on the support substrate 10SU.

The support substrate 10SU may comprise at least one or more selected from the group consisting of sintered body, BN, AlN, Al ₂ O ₃ , Ga ₂ O ₃ , diamond, carbon, and graphite. Here, the sintered body constituting the support substrate 10SU includes at least one type or a plurality of types of sintered bodies selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors. It's okay to be there. Also, the sintered body may comprise at least one or a plurality of sintered bodies selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

Further, as shown in FIG. 2(b), the substrate 10 may comprise a sintered body, and the substrate 10 and the epitaxial growth layer 12 may be bonded via a bonding interface layer 14. FIG. The sintered body may comprise at least one type or a plurality of types of sintered bodies selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors. Also, the sintered body may comprise at least one or a plurality of sintered bodies selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide. In the example of FIG. 2(b), the SiC sintered body 10SB and the SiC epitaxial growth layer (SiC-epi) 12 are bonded via the bonding interface layer (AIL) .

When using room temperature bonding, the surface roughness Ra of the substrate surface is set to about 1 nm or less. As a result, the thickness of the bonding interface layer (AIL) 14 having different compositions is set to approximately 1 nm to 10 μm.

When diffusion bonding is used, the surface roughness of the substrate surface may be rough depending on the material and bonding temperature. The thickness of the bonding interface layer (AIL) 14 having different composition gradients due to atomic diffusion is about 1 nm to 10 μm.

Still another schematic cross-sectional structure of a semiconductor substrate structure according to an embodiment to which the present technology is applied is represented as shown in FIG. , is represented as shown in FIG. 3(b). In the example of FIG. 3A, the SiC sintered body 10SB and the SiC epitaxial growth layer 12 are bonded via amorphous SiC as the bonding interface layer 14S. In the example of FIG. 3B, the SiC sintered body 10SB and the SiC epitaxial growth layer 12 are bonded via a metal layer as a bonding interface layer 14M. Here, the thickness of the bonding interface layers 14S and 14M is, for example, about 1 nm to 10 μm.

The junction interface layer may comprise at least one or a plurality of amorphous materials selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors.

Also, the bonding interface layer may comprise at least one or a plurality of amorphous materials selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

As shown in FIG. 3(a), the bonding interface layer 14S may comprise amorphous SiC.

Also, as shown in FIG. 3B, the bonding interface layer 14M may include a metal layer.

Here, the metal layer is at least one or more selected from the group of Al, Co, Ni, Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, Re, Os, Ir, Pt, and Au. may be provided.

Further, as shown in FIGS. 3A and 3B, the substrate 10 includes a silicon carbide sintered body, the epitaxial growth layer 12 includes a SiC epitaxial growth layer (SiC-epi), and the silicon carbide sintered The body 10SB and the SiC epitaxial growth layer (SiC-epi) 12 may be bonded via a bonding interface layer 14 .

According to the present embodiment, it is possible to provide a semiconductor substrate structure capable of eliminating restrictions on materials, reducing costs, and achieving desired physical properties, and a power semiconductor device having this semiconductor substrate structure.

According to the semiconductor substrate structure according to the present embodiment, instead of forming the SiC epitaxial growth layer on the SiC single crystal substrate, room temperature bonding technology or diffusion bonding technology is used to bond an arbitrary substrate and the SiC epitaxial growth layer. Because they are bonded together, the range of combinations of epitaxially grown layers and substrates can be expanded.

According to the semiconductor substrate structure according to the present embodiment, as a substrate material, for example, a low cost SiC polycrystalline substrate or a carbon substrate can be used instead of a high cost SiC single crystal substrate.

Moreover, according to the semiconductor substrate structure according to the present embodiment, it is possible to combine a substrate having desired characteristics and a SiC epitaxial growth layer, so that the characteristics of the power semiconductor device can be improved. Specifically, since the coefficient of thermal expansion, thermal conductivity, electrical conductivity, and mechanical properties can be combined as desired, the switching properties, heat resistance, and mechanical reliability of power semiconductor devices can be improved. be.

Further, according to the semiconductor substrate structure and the power semiconductor device having the semiconductor substrate structure according to the present embodiment, the room temperature bonding technique or the diffusion bonding technique is used to bond an arbitrary substrate and the completed SiC epitaxial growth layer. Since they are joined together, the period of the manufacturing process can be shortened. Also, since any substrate can be combined with the completed SiC epitaxial growth layer, the manufacturing yield can be improved.

(Manufacturing method of semiconductor substrate structure)
A method for manufacturing a semiconductor substrate structure 1 according to an embodiment to which the present technology is applied is illustrated as shown in FIGS. 4(a) and 4(b).

(a) First, as shown in FIG. 4(a), a SiC sintered body 10SB is formed.

(b) Next, a SiC epitaxial growth layer 12 is prepared separately from the SiC sintered body 10SB, and as shown in FIG. join by Also, the SiC sintered body 10SB and the SiC epitaxial growth layer 12 may be bonded by diffusion bonding.

(Room temperature bonding technology)
Room temperature bonding techniques include surface activated bonding techniques, plasma activated bonding techniques, atomic diffusion bonding techniques, and the like. Room-temperature bonding technology removes oxides and adsorbed molecules on the solid surface by sputtering effect using a high-speed atomic beam, etc. in a vacuum to activate the surface. It is a technology that forms In the room-temperature bonding technology, the bonding surfaces are treated in a vacuum to make the atoms on the surfaces active so as to easily form chemical bonds. Room-temperature bonding technology forms a strong bond by directly bonding atomic bonds on the surface by removing the surface layer that interferes with bonding. By using room temperature bonding technology, many materials can be bonded at room temperature.

As a semiconductor material, for example, Si, SiC, GaAs, InP, GaP, InAs, etc. can be applied to homogeneous bonding and mutual dissimilar material bonding. Si/LiNbO ₃ , Si/LiTaO ₃ , Si/Gd ₃ Ga ₅ O ₁₂ , Si/Al ₂ O ₃ (sapphire) and the like are applicable as single crystal oxides. Applicable metals include Au, Pt, Ag, Cu, Al, Sn, Pb, Zn, solder bulk materials, foils, bumps, and the like. In addition, the present invention can be applied to film materials, etc., in which Au, Pt, Cu, and Al are formed on a substrate. Also, as a metal/ceramic structure, it can be applied to joints of Al dissimilar materials such as Al/Al ₂ O ₃ , Al/silicon nitride, Al/SiC, and Al/AlN.

The room temperature bonding technology requires that the surfaces to be bonded be clean and smooth at the atomic level. Therefore, it is desirable that the surface roughness Ra of the surfaces to be joined is, for example, 1 nm or less. As a technique for reducing the surface roughness Ra to 1 nm or less, for example, a CMP technique or an MP technique can be applied. Alternatively, a high-speed atomic beam irradiation technique of argon, in which an ion beam is neutralized, may be applied.

Sputter etching using an ion beam, plasma, or the like, for example, can be applied to remove the surface layer. The surface after sputter etching is in a state of being susceptible to reaction with surrounding gas molecules. An inert gas such as argon is used for the ion beam, and the process is performed in a vacuum chamber evacuated to a high vacuum. After sputter-etching, the exposed surface of atoms having bonds is in an active state with strong bonding force with other atoms, and by bonding these atoms, a strong bond can be obtained at room temperature.

A description of room temperature bonding applicable to a method for manufacturing a semiconductor substrate structure according to an embodiment to which the present technology is applied, in which the first substrate 200 covered with a contaminant layer 200C is schematically shown in FIG. The second substrate 300 represented as shown in FIG. 5(a) and covered with the contaminant layer 300C is schematically represented as shown in FIG. 5(b).

The etching process for the surface of the first substrate covered with the contaminant layer 200C is schematically represented as shown in FIG. , is schematically represented as shown in FIG. 5(d). Here, the etching process is performed by irradiating a high-speed atomic beam from an argon high-speed ion beam generator 400 .

Furthermore, the manner in which the bond BD is formed between the cleaned active surface of the first substrate and the cleaned active surface of the second substrate is schematically shown in FIG. The step of bonding the active surface of the substrate and the active surface of the second substrate at room temperature is schematically shown in FIG. 5(f). Here, the steps of FIGS. 5(c) to 5(f) are all performed in a high vacuum state.

Here, the first substrate is, for example, the epitaxial growth layer 12 of the semiconductor substrate structure 1 according to one embodiment to which the present technology is applied, and the second substrate is, for example, to the one embodiment to which the present technology is applied. The substrate 10 of the semiconductor substrate structure 1 may be used.

In the room temperature bonding technique, a bonding interface layer is disposed between the cleaned first substrate active surface and the cleaned second substrate active surface, and the first substrate active surface and the second substrate Room temperature bonding of the substrate active surfaces is also possible. As the bonding interface layer, amorphous SiC 14S may be applied as shown in FIG. 3(a), or a metal layer 14M may be applied as shown in FIG. 3(b).

According to the manufacturing method of the semiconductor substrate structure according to the embodiment to which the present technology is applied, since damage to the bonding interface is small, productivity with high yield can be obtained.

(diffusion bonding technology)
Diffusion bonding technology is a technology in which base materials are brought into close contact with each other, pressure is applied at a temperature below the melting point of the base material to the extent that plastic deformation is minimized, and the diffusion of atoms occurring on the bonding surface is used for bonding.

An explanatory diagram of a diffusion bonding method applicable to a method of manufacturing a semiconductor substrate structure according to an embodiment to which the present technology is applied is shown in FIG.

When performing diffusion bonding, the materials to be bonded are brought into close contact with each other and heated and pressurized in a controlled atmosphere such as vacuum or inert gas. The heating temperature TH is, for example, approximately 200° C. to 350° C., and the pressure P is, for example, approximately 10 MPa to 80 MPa.

The example shown in FIG. 6 shows an example in which the SiC polycrystalline body 10SB and the SiC epitaxial growth layer 12 are heated and pressurized to perform diffusion bonding. In the example shown in FIG. 6, a void VD is formed at the bonding interface.

Description of a diffusion bonding method applicable to a method for manufacturing a semiconductor substrate structure according to an embodiment to which the present technology is applied, in which a SiC polycrystal 10SB is applied as a substrate and bonded onto the SiC polycrystal 10SB A configuration in which the SiC epitaxial growth layer 12 is arranged as a material is schematically represented as shown in FIG. 7(a). SiC polycrystalline body 10SB includes a plurality of SiC polycrystalline grains 15 .

The configuration in which the pressure/heating process is performed in the configuration of FIG. 7(a) is schematically represented as shown in FIG. 7(b), and the configuration in FIG. , and diffusion bonding is performed, and the configuration is schematically shown in FIG. 7(c). FIG. 7(b) is an example in which void VD is formed at the diffusion bonding interface, and FIG. 7(c) is an example in which void-free diffusion bonding is formed. As shown in FIGS. 7(a) to 7(c), in diffusion bonding, voids in the bonding portion disappear as the bonding progresses.

In diffusion bonding, it is also possible to bond the substrate and the bonding material via the bonding interface layer. As the bonding interface layer, amorphous SiC 14S may be applied as shown in FIG. 3(a), or a metal layer 14M may be applied as shown in FIG. 3(b).

In diffusion bonding, a metal layer may be sandwiched between the bonding surfaces to facilitate bonding. This metal layer is called an insert metal layer.

Description of the solid phase diffusion bonding method applicable to the manufacturing method of the semiconductor substrate structure according to one embodiment to which the present technology is applied, and the configuration in which the bonding material is arranged on the substrate via the insert metal layer 14M is , is schematically represented as shown in FIG. 8(a). A SiC polycrystalline body 10SB is applied as a substrate, and a SiC epitaxial growth layer 12 is applied as a bonding material.

The configuration in which the pressure and heating steps are performed in the configuration of FIG. 8A to form solid phase diffusion bonding is schematically represented as shown in FIG. 8(c) schematically shows a configuration in which the pressurizing/heating process is further performed and the solid phase diffusion bonding is progressed. In solid phase diffusion bonding, the insert metal layer 14M is bonded in a solid state.

In diffusion bonding and solid phase diffusion bonding, cleaning and adhesion are promoted on the bonding surface during the bonding process, and cleaning and adhesion are progressing simultaneously. Both the cleaning process and the adhesion process in diffusion bonding are due to diffusion phenomena.

Here, when amorphous SiC 14S is applied as the bonding interface layer, the amorphous SiC melts to form bonding, so liquid phase diffusion bonding or TLP (Transient Liquid Phase Diffusion Bonding) bonding is formed.

(Crystal state of ceramics)
It is an explanatory diagram of the crystalline state of ceramics, an example of a polycrystalline body is schematically shown in FIG. 9(a), and an example of an amorphous solid is schematically shown in FIG. 9(b) is represented as shown in Here, the crystal state of the SiC polycrystal is a crystalline solid and is schematically represented in the same manner as in FIG. 9A, while the crystal state of amorphous SiC is an amorphous solid and is schematically It is represented as shown in the same manner as in FIG. 9(b).

(Manufacturing equipment for SiC sintered body)
A polycrystalline body (SiC sintered body) manufacturing apparatus 500 for a semiconductor substrate structure according to an embodiment to which the present technology is applied is schematically represented as shown in FIG. The inside 500A of the polycrystalline body (SiC sintered body) manufacturing apparatus 500 is in a vacuum atmosphere of about several Pa or replaced with Ar/N ₂ gas.

A polycrystalline body (SiC sintered body) manufacturing apparatus 500 employs a solid compression sintering method by hot press sintering (HP: Hot Press). A graphite sintering mold (graphite die) 900 filled with powder or solid SiC polycrystalline material 940 is heated while being pressurized. Graphite die 900 houses a thermocouple or radiation thermometer 920 .

The graphite die 900 is connected to the pressing shafts 600A and 600B via graphite bunches 800A and 800B and graphite spacers 700A and 700B. SiC polycrystalline material 940 is pressurized and heated by pressurizing between pressing shafts 600A and 600B. The heating temperature is, for example, approximately 200° C. to 350° C., and the applied pressure P is, for example, approximately 50 MPa at maximum. In addition to hot press sintering (HP), for example, spark plasma sintering (SPS) may be applied.

According to the polycrystalline body (SiC sintered body) manufacturing apparatus 500 for a semiconductor substrate structure according to one embodiment to which the present technology is applied, the heating range is limited, so the temperature rises more rapidly than atmospheric heating in an electric furnace or the like. Heating and cooling are possible (several minutes to several hours). It is possible to produce a dense SiC sintered body that suppresses grain growth by applying pressure and rapidly raising the temperature. Moreover, it is applicable not only to sintering but also to sinter bonding, porous body sintering, and the like.

(graphite substrate)
As shown in FIG. 11, a semiconductor substrate structure 1 according to an embodiment to which the present technology is applied includes a graphite substrate 10GF and an epitaxial growth layer 12 bonded to the graphite substrate 10GF. 12 is joined by room temperature joining. Here, room temperature bonding includes at least one or a plurality of types selected from surface activated bonding, plasma activated bonding, and atomic diffusion bonding.

Also, the graphite substrate 10GF and the epitaxial growth layer 12 may be bonded by diffusion bonding.

The epitaxial growth layer 12 may comprise at least one or more selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors.

Also, the epitaxial growth layer 12 may comprise at least one or more selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

Also, the substrate 10 may comprise at least one or a plurality of materials selected from the group consisting of sintered bodies _, BN, _AlN , _Al2O3 , _Ga2O3 , diamond, carbon, and graphite. Here, the sintered body may include at least one type or a plurality of types of sintered bodies selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors. Also, the sintered body may comprise at least one or a plurality of sintered bodies selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

Also, the graphite substrate 10GF and the silicon carbide epitaxial growth layer 12 may be bonded via a bonding interface layer 14 .

When using room temperature bonding, the surface roughness Ra of the surface of the graphite substrate 10GF is set to about 1 nm or less. As a result, the thickness of the bonding interface layer (AIL) 14 having different compositions is set to approximately 1 nm to 10 μm.

When diffusion bonding is used, the surface roughness may be rough depending on the material and bonding temperature. The thickness of the bonding interface layer (AIL) 14 having different composition gradients due to atomic diffusion is about 1 nm to 10 μm.

Also, the bonding interface layer 14 may comprise a metal layer.

Here, the metal layer is at least one or more selected from the group of Al, Co, Ni, Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, Re, Os, Ir, Pt, and Au. may be provided.

The junction interface layer 14 may comprise at least one or a plurality of amorphous materials selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors.

Also, the bonding interface layer may comprise at least one or a plurality of amorphous materials selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

Graphite substrate 10GF applicable to semiconductor substrate structure 1 according to an embodiment to which the present technology is applied has, as shown in FIG. 12, a laminated structure of graphite sheets GS1, GS2, GS3, . The graphite sheets GS1, GS2, GS3, . . . . GSn are coupled by van der Waals force.

Graphite substrate 10GF, which is a carbon-based anisotropic heat transfer material, is a layered crystal body with a hexagonal network structure of carbon atoms, and has anisotropic heat conduction. GS3 . . . GSn have a larger thermal conductivity (higher thermal conductivity) in the crystal plane direction (on the XY plane) than in the Z-axis thickness direction.

FIG. 13A shows a schematic bird's-eye view configuration of an XY-oriented graphite substrate 10GF (XY), which is an example of a graphite substrate 10GF applicable to a semiconductor substrate structure 1 according to an embodiment to which the present technology is applied. , and a schematic bird's-eye view configuration of the XZ-oriented graphite substrate 10GF (XZ) is represented as shown in FIG. 13(b).

In the graphite substrate 10GF, two types of graphite substrates 10GF(XY) and 10GF(XZ) with different orientations can be used.

The graphite substrate 10GF includes a graphite substrate 10GF (XY) having an XY orientation (first orientation) with higher thermal conductivity in the plane direction than in the thickness direction, and an XZ orientation having higher thermal conductivity in the thickness direction than in the plane direction. Graphite substrate 10GF(XZ) with (second orientation). As shown in FIG. 13A, the graphite substrate 10GF (XY) having XY orientation has, for example, X=1500 (W/mK), Y=1500 (W/mK), Z=5 (W/mK). It has a thermal conductivity of On the other hand, as shown in FIG. 13B, the XZ-oriented graphite substrate 10GF (XZ) is, for example, X = 1500 (W/mK), Y = 5 (W/mK), Z = 1500 (W/mK). mK). The graphite plates 10GF(XY) and 10GF(XZ) both have a density of 2.2 (g/cm ³ ).

The semiconductor substrate structure 1 according to one embodiment to which the present technology described above is applied can be used, for example, for manufacturing various SiC semiconductor devices. Below, SiC Schottky barrier diode (SBD: Schottky Barrier Diode), SiC trench gate (T: Trench) type metal oxide semiconductor field effect transistor (MOSFET: Metal Oxide Semiconductor Field Effect Transistor), and SiC An example of a planar gate MOSFET is shown.

(SiC-SBD)
A SiC-SBD 21 manufactured using a semiconductor substrate structure according to an embodiment to which the present technology is applied is, as shown in FIG. Prepare. The SiC sintered body 10SB and the SiC epitaxial growth layer 12 are bonded by normal temperature bonding or diffusion bonding. A bonding interface layer 14 may be interposed between the SiC sintered body 10SB and the SiC epitaxial growth layer 12 .

The SiC sintered body 10SB is doped to n ⁺ type (impurity density is, for example, about 1×10 ¹⁸ cm ⁻³ to about 1×10 ²¹ cm ⁻³ ), and the SiC epitaxial growth layer 12 is doped to n ⁻ type (impurity doped to a density of, for example, about 5×10 ¹⁴ cm ⁻³ to about 5×10 ¹⁶ cm ⁻³ ).

Also, the SiC epitaxial growth layer 12 may be made of any one of 4H-SiC, 6H-SiC, 2H-SiC, or 3C-SiC.

Also, any one of BN, AlN, Al ₂ O ₃ , Ga ₂ O ₃ , diamond, carbon, or graphite may be provided instead of the SiC sintered body 10SB.

As n-type doping impurities, for example, N (nitrogen), P (phosphorus), As (arsenic), etc. can be applied.

As the p-type doping impurity, for example, TMA or the like can be applied.

A cathode electrode 22 is provided on the back surface of the SiC sintered body 10SB so as to cover the entire area thereof, and the cathode electrode 22 is connected to a cathode terminal K. As shown in FIG.

A surface 100 (for example, (0001) Si plane) of the SiC epitaxial growth layer 12 has a contact hole 24 that exposes a part of the SiC epitaxial growth layer 12 as an active region 23, and a field region 25 surrounding the active region 23 has a , a field insulating film 26 is formed.

The field insulating film 26 is made of SiO ₂ (silicon oxide), but may be made of other insulators such as silicon nitride (SiN). An anode electrode 27 is formed on the field insulating film 26, and the anode electrode 27 is connected to the anode terminal A. As shown in FIG.

A p-type JTE (Junction Termination Extension) structure 28 is formed in the vicinity of the surface 100 (surface layer portion) of the SiC epitaxial growth layer 12 so as to be in contact with the anode electrode 27 . The JTE structure 28 is formed along the contour of the contact hole 24 so as to straddle the inside and outside of the contact hole 24 of the field insulating film 26 .

(SiC-TMOSFET)
A trench gate type MOSFET 31 manufactured using a semiconductor substrate structure according to an embodiment to which the present technology is applied is, as shown in FIG. 1. The SiC sintered body 10SB and the SiC epitaxial growth layer 12 are bonded by normal temperature bonding or diffusion bonding. A bonding interface layer 14 may be interposed between the SiC sintered body 10SB and the SiC epitaxial growth layer 12 .

The SiC sintered body 10SB is doped to n ⁺ type (impurity density is, for example, about 1×10 ¹⁸ cm ⁻³ to about 1×10 ²¹ cm ⁻³ ), and the SiC epitaxial growth layer 12 is doped to n ⁻ type (impurity doped to a density of, for example, about 5×10 ¹⁴ cm ⁻³ to about 5×10 ¹⁶ cm ⁻³ ).

Also, the SiC epitaxial growth layer 12 may be made of any one of 4H-SiC, 6H-SiC, 2H-SiC, or 3C-SiC.

Also, any one of BN, AlN, Al ₂ O ₃ , Ga ₂ O ₃ , diamond, carbon, or graphite may be provided instead of the SiC sintered body 10SB.

As n-type doping impurities, for example, N (nitrogen), P (phosphorus), As (arsenic), etc. can be applied.

As the p-type doping impurity, for example, TMA or the like can be applied.

The back surface ((000-1)C plane) of the SiC sintered body 10SB is provided with a drain electrode 32 which is connected to the drain terminal D so as to cover the entire area thereof.

In the vicinity (surface layer portion) of the surface 100 ((0001) Si plane) of the SiC epitaxial growth layer 12, p-type (impurity density is, for example, about 1×10 ¹⁶ cm ⁻³ to about 1×10 ¹⁹ cm ⁻³ ). A body region 33 is formed. In the SiC epitaxial growth layer 12, the portion on the side of the SiC sintered body 10SB with respect to the body region 33 is the n ⁻ -type drain region 34 (12) where the state of the SiC epitaxial growth layer is maintained.

A gate trench 35 is formed in the SiC epitaxial growth layer 12 . Gate trench 35 penetrates body region 33 from surface 100 of SiC epitaxial growth layer 12 and reaches drain region 34 at its deepest portion.

A gate insulating film 36 is formed on the inner surface of the gate trench 35 and the surface 100 of the SiC epitaxial growth layer 12 so as to cover the entire inner surface of the gate trench 35 . Gate electrode 37 is buried in gate trench 35 by filling the inside of gate insulating film 36 with, for example, polysilicon. A gate terminal G is connected to the gate electrode 37 .

An n ⁺ -type source region 38 forming part of the side surface of the gate trench 35 is formed in the surface layer portion of the body region 33 .

In the SiC epitaxial growth layer 12, p ⁺ -type (impurity density is, for example, about 1×10 ¹⁸ cm ⁻³ to about 1×10 ²¹ cm ^-3 ) of body contact region 39 is formed.

An interlayer insulating film 40 made of SiO ₂ is formed on the SiC epitaxial growth layer 12 . A source electrode 42 is connected to the source region 38 and the body contact region 39 through a contact hole 41 formed in the interlayer insulating film 40 . A source terminal S is connected to the source electrode 42 .

By applying a predetermined voltage (a voltage equal to or higher than the gate threshold voltage) to the gate electrode 37 in a state where a predetermined potential difference is generated between the source electrode 42 and the drain electrode 32 (between the source and the drain), the gate electrode A channel can be formed near the interface with the gate insulating film 36 in the body region 33 by the electric field from 37 . Thereby, a current can flow between the source electrode 42 and the drain electrode 32, and the SiC-TMOSFET 31 can be turned on.

(SiC planar gate type MOSFET)
A planar gate type MOSFET 51 manufactured using a semiconductor substrate structure 1 according to an embodiment to which the present technology is applied has a semiconductor substrate structure including a SiC sintered body 10SB and a SiC epitaxial growth layer 12, as shown in FIG. It has a body 1. The SiC sintered body 10SB and the SiC epitaxial growth layer 12 are bonded by normal temperature bonding or diffusion bonding. A bonding interface layer 14 may be interposed between the SiC sintered body 10SB and the SiC epitaxial growth layer 12 .

The SiC sintered body 10SB is doped to n ⁺ type (impurity density is, for example, about 1×10 ¹⁸ cm ⁻³ to about 1×10 ²¹ cm ⁻³ ), and the SiC epitaxial growth layer 12 is doped to n ⁻ type (impurity doped to a density of, for example, about 5×10 ¹⁴ cm ⁻³ to about 5×10 ¹⁶ cm ⁻³ ).

Also, the SiC epitaxial growth layer 12 may be made of any one of 4H-SiC, 6H-SiC, 2H-SiC, or 3C-SiC.

Also, any one of BN, AlN, Al ₂ O ₃ , Ga ₂ O ₃ , diamond, carbon, or graphite may be provided instead of the SiC sintered body 10SB.

As n-type doping impurities, for example, N (nitrogen), P (phosphorus), As (arsenic), etc. can be applied.

As the p-type doping impurity, for example, TMA or the like can be applied.

A drain electrode 52 is formed on the back surface ((000-1)C plane) of the SiC sintered body 10SB so as to cover the entire area, and a drain terminal D is connected to the drain electrode 52 .

In the vicinity (surface layer portion) of the surface 100 ((0001) Si plane) of the SiC epitaxial growth layer 12, p-type (impurity density is, for example, about 1×10 ¹⁶ cm ⁻³ to about 1×10 ¹⁹ cm ⁻³ ). A body region 53 is formed in a well shape. In the SiC epitaxial growth layer 12, the portion on the side of the SiC substrate 2 with respect to the body region 53 is the n ⁻ -type drain region 54 (12), which is maintained as it is after the epitaxial growth.

An n ⁺ -type source region 55 is formed in the surface layer portion of the body region 53 with a gap from the periphery of the body region 53 .

Inside the source region 55, a p ⁺ -type (impurity density is, for example, about 1×10 ¹⁸ cm ⁻³ to about 1×10 ²¹ cm ⁻³ ) body contact region 56 is formed. Body contact region 56 penetrates source region 55 in the depth direction and is connected to body region 53 .

A gate insulating film 57 is formed on the surface 100 of the SiC epitaxial growth layer 12 . The gate insulating film 57 covers the portion of the body region 53 surrounding the source region 55 (periphery of the body region 53 ) and the outer periphery of the source region 55 .

A gate electrode 58 made of, for example, polysilicon is formed on gate insulating film 57 . The gate electrode 58 faces the peripheral portion of the body region 53 with the gate insulating film 57 interposed therebetween. A gate terminal G is connected to the gate electrode 58 .

An interlayer insulating film 59 made of SiO ₂ is formed on the SiC epitaxial growth layer 12 . A source electrode 61 is connected to the source region 55 and the body contact region 56 through a contact hole 60 formed in the interlayer insulating film 59 . A source terminal S is connected to the source electrode 61 .

By applying a predetermined voltage (a voltage equal to or higher than the gate threshold voltage) to the gate electrode 58 in a state where a predetermined potential difference is generated between the source electrode 61 and the drain electrode 52 (between the source and the drain), the gate electrode A channel can be formed near the interface with the gate insulating film 57 in the body region 53 by the electric field from 58 . Thereby, a current can flow between the source electrode 61 and the drain electrode 52, and the planar gate type MOSFET 51 can be turned on.

As mentioned above, although this embodiment was described, it can also implement in another form.

For example, although illustration is omitted, a vertical device structure can also be manufactured using the semiconductor substrate structure 1 according to one embodiment to which the present technology is applied. That is, a vertical power semiconductor device comprising a substrate, an epitaxially grown layer that is room temperature bonded or diffusion bonded to the substrate, and a first metal electrode that is disposed on the surface of the substrate facing the bonding surface between the substrate and the epitaxially grown layer is formed. can be

Also, a vertical power semiconductor device may be formed further comprising a second metal electrode arranged on the surface of the epitaxial growth layer facing the junction surface between the substrate and the epitaxial growth layer.

Further, for example, a lateral device structure can be manufactured using the semiconductor substrate structure 1 according to one embodiment to which the present technology is applied. That is, a horizontal power semiconductor device comprising a substrate, an epitaxial growth layer that is room temperature bonded or diffusion bonded to the substrate, and a second metal electrode that is disposed on the surface of the epitaxial growth layer facing the bonding surface between the substrate and the epitaxial growth layer is formed. can be

Also in the above vertical or horizontal power semiconductor device, the epitaxially grown layer comprises at least one or more selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors. Also good. Also, the epitaxial growth layer may comprise at least one or more selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

Also in the above vertical or horizontal power semiconductor device, the substrate is at least one or more selected from the group consisting of sintered body, BN, AlN, Al ₂ O ₃ , Ga ₂ O ₃ , diamond, carbon, and graphite. may be provided. Also, the sintered body may comprise at least one type or a plurality of types of sintered bodies selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors. Also, the sintered body may comprise at least one or a plurality of sintered bodies selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

Further, for example, although illustration is omitted, a MOS capacitor can also be manufactured using the semiconductor substrate structure 1 according to one embodiment to which the present technology is applied. MOS capacitors can improve yield and reliability.

Moreover, although illustration is omitted, a bipolar transistor can also be manufactured using the semiconductor substrate structure 1 according to one embodiment to which the present technology is applied. In addition, the semiconductor substrate structure 1 according to the embodiment can also be used for manufacturing SiC-pn diodes, SiC insulated gate bipolar transistors (IGBTs), SiC complementary MOSFETs, and the like.

A schematic bird's-eye view configuration of a semiconductor substrate structure (wafer) 1 according to an embodiment to which the present technology is applied is, as shown in FIG. and the substrate 10 and the epitaxially grown layer are bonded by room temperature bonding. Here, room temperature bonding includes at least one or a plurality of types selected from surface activated bonding, plasma activated bonding, and atomic diffusion bonding.

Also, the substrate 10 and the epitaxial growth layer 12 may be bonded by diffusion bonding.

When using room temperature bonding, the surface roughness Ra of the substrate surface is set to about 1 nm or less. As a result, the thickness of the bonding interface layer (AIL) 14 having different compositions is set to approximately 1 nm to 10 μm.

When diffusion bonding is used, the surface roughness of the substrate surface may be rough depending on the material and bonding temperature. The thickness of the bonding interface layer (AIL) 14 having different composition gradients due to atomic diffusion is about 1 nm to 10 μm.

The epitaxial growth layer 12 may comprise at least one or more selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors.

The epitaxial growth layer 12 may comprise at least one or more selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

Also, the SiC epitaxial growth layer may be made of any one of 4H-SiC, 6H-SiC, 2H-SiC, and 3C-SiC.

The substrate 10 may comprise at least one or more selected from the group consisting of sintered body, BN, AlN, Al ₂ O ₃ , Ga ₂ O ₃ , diamond, carbon, and graphite.

Here, the sintered body may include at least one type or a plurality of types of sintered bodies selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors. Also, the sintered body may comprise at least one or a plurality of sintered bodies selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

The SiC epitaxial growth layer 12 may be made of, for example, 4H—SiC and have an off angle of less than 4 degrees.

The thickness of the substrate (SiC sintered body) 10 is, for example, approximately 200 μm to approximately 500 μm, and the thickness of the SiC epitaxial growth layer 12 is, for example, approximately 4 μm to approximately 100 μm.

As shown in FIG. 17B, a schematic bird's-eye view configuration (an example including a bonding interface layer) of a semiconductor substrate structure (wafer) 1 according to an embodiment to which the present technology is applied includes a substrate 10 and a substrate 10 and an epitaxial growth layer 12 bonded to the substrate and the epitaxial growth layer 12 are bonded via a bonding interface layer 14 .

Here, the bonding interface layer 14 may comprise a metal layer.

Here, the metal layer is at least one or more selected from the group of Al, Co, Ni, Nb, Mo, Ru, Rh, Pd, Ag, Ta, W, Re, Os, Ir, Pt, and Au. may be provided.

The junction interface layer 14 may comprise at least one or a plurality of amorphous materials selected from the group of IV group element semiconductors, III-V group compound semiconductors, and II-VI group compound semiconductors.

Also, the bonding interface layer may comprise at least one or a plurality of amorphous materials selected from the group consisting of silicon carbide, gallium nitride, silicon, aluminum nitride, and gallium oxide.

(SiC epitaxial wafer)
The SiC epitaxial growth layer 12 may be made of, for example, 4H—SiC and have an off angle of less than 4 degrees. The thickness of the substrate (SiC sintered body) 10 is, for example, approximately 200 μm to approximately 500 μm, and the thickness of the SiC epitaxial growth layer 12 is, for example, approximately 4 μm to approximately 100 μm.

(Crystal structure example)
A schematic bird's-eye view configuration of a 4H—SiC crystal unit cell applicable to the SiC epitaxial growth layer 12 is shown in FIG. (b), and the schematic configuration of the 4-layer portion of the 4H—SiC crystal is represented as shown in FIG. 18(c).

FIG. 19 shows a schematic configuration of the unit cell of the 4H—SiC crystal structure shown in FIG. 18(a) viewed from directly above the (0001) plane.

As shown in FIGS. 18(a) to 18(c), the crystal structure of 4H—SiC can be approximated by a hexagonal system, and four C atoms are bonded to one Si atom. . The four C atoms are located at the four vertices of a regular tetrahedron centered on the Si atom. These four C atoms are arranged such that one Si atom is located on the [0001] axis direction with respect to the C atom and the other three C atoms are located on the [000-1] axis side with respect to the Si atom. there is In FIG. 18(a), the off angle θ is, for example, about 4 degrees or less.

The [0001] axis and the [000-1] axis are along the axial direction of the hexagonal prism, and the plane normal to the [0001] axis (the top surface of the hexagonal prism) is the (0001) plane (Si plane). On the other hand, the plane normal to the [000-1] axis (the lower surface of the hexagonal prism) is the (000-1) plane (C plane).

In addition, the directions that are perpendicular to the [0001] axis and that pass through non-adjacent vertices of the hexagonal prism when viewed from directly above the (0001) plane are the a1 axis [2-1-10] and the a2 axis, respectively. [-12-10] and a3 axis [-1-120].

As shown in FIG. 19, the direction passing through the vertices between the a1 and a2 axes is the [11-20] axis, and the direction passing through the vertices between the a2 and a3 axes is the [-2110] axis. , and the direction passing through the vertex between the a3 axis and the a1 axis is the [1-210] axis.

Between each of the six axes passing through each vertex of the hexagonal prism, the axes that are inclined at an angle of 30° with respect to the axes on both sides thereof and that are normal to each side surface of the hexagonal prism are respectively a1 [10-10] axis, [1-100] axis, [0-110] axis, [-1010] axis, [-1100] axis and [01-10] axis. Each plane (side surface of the hexagonal prism) normal to these axes is a crystal plane perpendicular to the (0001) plane and the (000-1) plane.

A power semiconductor device including the semiconductor substrate structure according to the present embodiment may include any one of SiC-based, Si-based, GaN-based, AlN-based, and gallium oxide-based IGBTs, diodes, MOSFETs, and thyristors.

A power semiconductor device including a semiconductor substrate structure according to the present embodiment can be any one of a one-in-one module, a two-in-one module, a four-in-one module, a six-in-one module, a seven-in-one module, an eight-in-one module, a twelve-in-one module, and a four-in-one module. It may be provided with the following configuration.

According to this embodiment, it is possible to provide a semiconductor substrate structure having a stable interface structure even at high temperatures, and a power semiconductor device having this semiconductor substrate structure.

According to the present embodiment, it is possible to provide a semiconductor substrate structure capable of eliminating restrictions on materials, reducing costs, and achieving desired physical properties, and a power semiconductor device having this semiconductor substrate structure.

According to the semiconductor substrate structure according to the present embodiment, instead of forming the SiC epitaxial growth layer on the SiC single crystal substrate, room temperature bonding technology or diffusion bonding technology is used to bond an arbitrary substrate and the SiC epitaxial growth layer. Because they are bonded together, the range of combinations of epitaxially grown layers and substrates can be expanded.

According to the semiconductor substrate structure according to the present embodiment, as a substrate material, for example, a low cost SiC polycrystalline substrate or a carbon substrate can be used instead of a high cost SiC single crystal substrate.

Moreover, according to the semiconductor substrate structure according to the present embodiment, it is possible to combine a substrate having desired characteristics and a SiC epitaxial growth layer, so that the characteristics of the power semiconductor device can be improved. Specifically, since the coefficient of thermal expansion, thermal conductivity, electrical conductivity, and mechanical properties can be combined as desired, the switching properties, heat resistance, and mechanical reliability of power semiconductor devices can be improved. be.

Further, according to the semiconductor substrate structure and the power semiconductor device having the semiconductor substrate structure according to the present embodiment, the room temperature bonding technique or the diffusion bonding technique is used to bond an arbitrary substrate and the completed SiC epitaxial growth layer. Since they are joined together, the process period can be shortened. Also, since any substrate can be combined with the completed SiC epitaxial growth layer, the manufacturing yield can be improved.

[Other embodiments]
As noted above, although several embodiments have been described, the discussion and drawings forming part of the disclosure are to be understood as illustrative and not limiting. Various alternative embodiments, implementations and operational techniques will become apparent to those skilled in the art from this disclosure.

Thus, this embodiment includes various embodiments and the like that are not described here.

The semiconductor substrate structure of the present embodiment and the power semiconductor device having this semiconductor substrate structure can be applied to various semiconductor module technologies such as IGBT modules, diode modules, and MOS modules (Si, SiC, GaN, AlN, gallium oxide). Power modules for inverter circuits that drive electric motors used as power sources for electric vehicles (including hybrid vehicles), trains, industrial robots, etc., solar cells, wind power generators, and other power generation It can be applied to a wide range of application fields such as a power module for an inverter circuit that converts the power generated by a device (especially a private power generator) into the power of a commercial power supply.

REFERENCE SIGNS LIST 1 semiconductor substrate structure 10 substrate 10GF graphite substrate 10SB SiC sintered body 12 SiC epitaxial growth layer 14 bonding interface layer 14S bonding interface layer (amorphous SiC) 14M bonding Interface layer (metal layer) 21 Power semiconductor device (SiC-SBD) 31 Power semiconductor device (SiC-TMOSFET) Power semiconductor device (SiC-MOSFET) 500 Polycrystalline body (SiC sintered body) production Device, 940... SiC polycrystalline material, GS (GS1, GS2, GS3, ..., GSn)... graphite sheet, S... source terminal, D... drain terminal, G... gate terminal, A... anode terminal, K... cathode terminal

Claims (10)

providing a substrate and an epitaxially grown layer;
etching the respective surfaces of the substrate and the epitaxially grown layer in a vacuum to expose atoms having bonds on each surface;
A method for manufacturing a semiconductor substrate structure, comprising: bonding the substrate and the epitaxially grown layer at room temperature in a vacuum. 2. The method of manufacturing a semiconductor substrate structure according to claim 1, wherein the etching uses ion beam or plasma sputter etching. 2. The method of manufacturing a semiconductor substrate structure according to claim 1, wherein said etching is performed by irradiating a fast atom beam from an argon fast ion beam generator. 2. The method of manufacturing a semiconductor substrate structure according to claim 1, wherein said etching is performed in a vacuum chamber evacuated to a high vacuum. providing a substrate and an epitaxially grown layer;
bringing the respective surfaces of the substrate and the epitaxial growth layer into close contact;
A method for fabricating a semiconductor substrate structure, comprising heating and pressurizing the substrate and the epitaxial growth layer, which are brought into close contact with each other, in a controlled atmosphere of vacuum or inert gas to diffusion bond them. 6. The method for manufacturing a semiconductor substrate structure according to claim 5, wherein said heating temperature is about 200.degree. C. to 350.degree. C., and said pressure is about 10 MPa to 80 MPa. 6. The method of manufacturing a semiconductor substrate structure according to claim 5, wherein said diffusion bonding is solid phase diffusion bonding. 6. The method of manufacturing a semiconductor substrate structure according to claim 5, wherein said diffusion bonding is liquid phase diffusion bonding. A semiconductor substrate structure manufactured by the manufacturing method according to claim 1,
the substrate;
and said epitaxially grown layer bonded to said substrate. A semiconductor substrate structure manufactured by the manufacturing method according to claim 5,
the substrate;
and said epitaxially grown layer bonded to said substrate.

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