CN100505164C - Method for manufacturing nitride semiconductor substrate and composite material substrate - Google Patents

Abstract

A method for manufacturing a nitride semiconductor substrate includes providing a first substrate including a first base, a nitride semiconductor template layer stacked on the first base, and a first dielectric layer stacked on the nitride semiconductor template layer. Then, the first dielectric layer and the nitride semiconductor template layer are patterned, and a second substrate is provided and comprises a second base material and a second dielectric layer stacked on the second base material. And then, transferring the nitride semiconductor template layer of the first substrate and the first dielectric layer to a second dielectric layer of a second substrate by a bonding transfer process, and then growing a layer of nitride semiconductor thick film from the nitride semiconductor template layer by utilizing an epitaxial process. Thereafter, the nitride semiconductor thick film is separated from the second substrate.

Description

Manufacturing method of nitride semiconductor substrate and composite material substrate

technical field

The present invention relates to a method for manufacturing a nitride semiconductor substrate, and in particular to a method for manufacturing a nitride semiconductor substrate capable of forming a low defect density and a composite compound with a patterned structure prepared by the above method. Material substrate (composite material substrate).

Background technique

In recent years, gallium nitride and related ternary compound semiconductors have been widely used in short-wavelength optoelectronic components and high-power high-frequency components, but because gallium nitride substrates are not easy to manufacture, they are often grown on other types of on substrates, such as single crystal alumina substrates and silicon carbide substrates. Although GaN single crystals have been successfully grown on these two substrates using heteroepitaxial (Heteropeitaxy) technology, however, due to lattice mismatch, a high density of defects is usually caused during the epitaxy process, and these The disadvantages will limit the application and development of gallium nitride materials in optoelectronic semiconductor components.

Generally speaking, the limitation of the solubility and diffusion coefficient of nitrogen in liquid gallium makes it difficult to complete the fabrication of gallium nitride substrates by traditional single crystal pulling technology. Therefore, in recent years, the Hydride Vapor Phase Epitaxy (HVPE) method has been developed, and this technology is used to greatly increase the thickness of GaN on the sapphire substrate to grow GaN thick films, but the defect density and However, macro cracks cannot be effectively and greatly reduced. The most important factor is the difference in lattice constant and thermal expansion coefficient of heterogeneous materials.

At present, there have been patents for manufacturing gallium nitride substrates with low defect density, such as US Pat. No. 6,964,914. This patent is mainly to perform hydrogen ion (H ⁺ ) implantation on the single crystal substrate of gallium nitride or aluminum nitride first, and the depth of implantation is the thickness after transfer in the future. Then, after the implantation is completed, the thin gallium nitride layer is transferred to other supporting substrates using direct-wafer-bonding or intermediate-wafer-bonding technology. The single crystal layer is called the nucleation layer. Next, a thick gallium nitride single crystal layer is grown by hydride vapor phase epitaxy, and finally, the gallium nitride thick film and the supporting substrate are separated.

However, although the above-mentioned U.S. patent can produce a thick film of gallium nitride without support (free standing), there are several disadvantages in this patent. The following points are explained: the bonding temperature is as high as 800 during the wafer bonding process. ~1000°C, during the separation and transfer process of the thin nucleation layer, the temperature is also as high as 900~950°C, high temperature will cause gallium nitride or supporting substrate to crack due to the difference in thermal expansion coefficient. In addition, using a GaN substrate as a nucleation seed material seems to be insufficient in cost, because the current cost of this substrate is as high as US$10,000, which is evident in the high cost.

Contents of the invention

The object of the present invention is to provide a method for manufacturing a nitride semiconductor substrate to obtain a semiconductor substrate with low defect density.

Another object of the present invention is to provide a composite material substrate with a pattern structure, which is suitable for growing a nitride semiconductor substrate with low defect density.

The present invention proposes a method for manufacturing a nitride semiconductor substrate, which includes providing a first substrate first, and the first substrate includes a first base material, a nitride semiconductor template layer stacked on the first base material, and a nitride semiconductor template layer stacked on the first base material. The first dielectric layer on the nitride semiconductor template layer. Next, the first dielectric layer and the nitride semiconductor template layer are patterned, and a second substrate is provided, and the second substrate includes a second substrate and a second dielectric layer stacked on the second substrate. Subsequently, the nitride semiconductor template layer and the first dielectric layer of the first substrate are transferred to the second dielectric layer of the second substrate by a bonding and transfer process, and then an epitaxial process is used from the nitride semiconductor A thick nitride semiconductor film is grown on the template layer. After that, the nitride semiconductor thick film is separated from the second substrate.

According to the manufacturing method described in the preferred embodiment of the present invention, the method for patterning the first dielectric layer and the nitride semiconductor template layer includes photolithography. Moreover, the step of patterning the first dielectric layer and the nitride semiconductor template layer includes first patterning the first dielectric layer, and then using the patterned first dielectric layer as an etching mask to etch the nitride semiconductor template layer.

According to the manufacturing method described in the preferred embodiment of the present invention, wherein the method for patterning the first dielectric layer and the nitride semiconductor template layer includes making the first dielectric layer and the nitride semiconductor template layer to have a linear, mesh or dot pattern. distribution pattern.

According to the manufacturing method described in the preferred embodiment of the present invention, the materials of the first dielectric layer and the second dielectric layer each independently include SiO ₂ , Si ₃ N ₄ or spin on glass (SOG).

According to the manufacturing method described in the preferred embodiment of the present invention, the material of the second substrate includes sapphire, silicon (Si), GaP, InP, quartz (Quartz), high temperature resistant glass or ceramic material.

According to the manufacturing method described in the preferred embodiment of the present invention, wherein the epitaxy process includes hydride vapor phase epitaxy (HVPE), metal-organic vapor phase epitaxy (Metal-Organic chemical vapordeposition, MOCVD) or molecular beam epitaxy (Molecular Beam Epitaxy, MBE ).

According to the manufacturing method described in the preferred embodiment of the present invention, the method of separating the nitride semiconductor thick film from the second substrate includes chemical etching or mechanical force separation. The chemical etching solution includes HF or buffered oxide etching solution (Buffered Oxide Etch, BOE). In addition, the method of separating the nitride semiconductor thick film from the second substrate includes using chemical etching and mechanical force alternately at the same time to accelerate the separation.

According to the manufacturing method described in the preferred embodiment of the present invention, after providing the second substrate, it further includes patterning the surface of the second dielectric layer, so as to help the intrusion of the chemical etching solution.

According to the manufacturing method described in the preferred embodiment of the present invention, after transferring the nitride semiconductor template layer and the first dielectric layer of the first substrate to the second dielectric layer of the second substrate, further comprising: The template layer is subjected to chemical mechanical polishing or reactive ion etching to obtain an epitaxial grade surface.

According to the manufacturing method described in the preferred embodiment of the present invention, after separating the nitride semiconductor thick film and the second substrate, it further includes performing a surface grinding process on the nitride semiconductor thick film.

According to the manufacturing method described in the preferred embodiment of the present invention, the material of the nitride semiconductor thick film includes gallium nitride or aluminum nitride.

The present invention further proposes a composite material substrate with a pattern structure, including a substrate, a first dielectric layer, a second dielectric layer and a nitride semiconductor material. Wherein, the first dielectric layer is stacked on the surface of the substrate, the second dielectric layer is stacked on the surface of the first dielectric layer, and the nitride semiconductor material is stacked on the surface of the second dielectric, which is characterized in that the nitride semiconductor material has Multiple patterns of nitride semiconductor material.

According to the composite material substrate described in the preferred embodiment of the present invention, the above-mentioned pattern includes a linear pattern, a mesh pattern, or a dot pattern pattern.

According to the composite material substrate described in the preferred embodiment of the present invention, the material of the substrate includes high temperature resistant materials such as sapphire, silicon, GaP, InP, quartz, glass or ceramic materials.

According to the composite material substrate described in the preferred embodiment of the present invention, the materials of the first dielectric layer and the second dielectric layer each independently include SiO ₂ , Si ₃ N ₄ or spin-on-coated glass.

According to the composite material substrate according to the preferred embodiment of the present invention, the material of the nitride semiconductor material includes at least one of indium (In), aluminum (Al) and gallium (Ga).

The composite material substrate according to the preferred embodiment of the present invention is suitable for making a freestanding nitride semiconductor substrate.

In the present invention, the nitride semiconductor template layer (template layer) is first patterned when making the nitride semiconductor substrate to greatly reduce the defect density during subsequent epitaxial growth, and then the nitride semiconductor template layer is transferred to the heterogeneous substrate by wafer bonding. The bottom serves as a single crystal seed layer. In addition, finally, a nitride semiconductor substrate with low defect density can be obtained through mechanical self-separation or chemical etching separation.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, the present invention will be described in more detail below with reference to the accompanying drawings and preferred embodiments.

Description of drawings

1A to 1I are cross-sectional views of a manufacturing process of a nitride semiconductor substrate according to a preferred embodiment of the present invention.

Fig. 2 is a structural sectional view of a composite material substrate with a pattern structure according to another preferred embodiment of the present invention.

simple notation

100: first substrate

104, 104a: nitride semiconductor template layer

105: The surface of the epitaxial level

106, 106a: the first dielectric layer

108: Nitride semiconductor thick film

110: second substrate

112: Second substrate

114: Second dielectric layer

116: sharp blade

200: Substrate

202: The first dielectric layer

204: Second dielectric layer

206: Nitride semiconductor materials

208: pattern

Detailed ways

1A to 1I are cross-sectional views of a manufacturing process of a nitride semiconductor substrate according to a preferred embodiment of the present invention.

1A, a first substrate 100 is provided, which includes a first substrate 102, a nitride semiconductor template layer 104 stacked on the first substrate 102, and a nitride semiconductor template layer 104 stacked on the A first dielectric layer 106. Wherein, the material of the nitride semiconductor template layer 104 is, for example, a semiconductor material containing one of indium (In), aluminum (Al) and gallium (Ga), such as GaN, AlN, InN, AlGaN, InGaN or AlInN. The first substrate 102 is an epitaxial substrate, such as sapphire, SiC or silicon substrate. The material of the first dielectric layer 106 may be SiO ₂ , Si ₃ N ₄ , spin-on-glass or other suitable materials.

Please continue to refer to FIG. 1A , each layer shown therein (ie, the nitride semiconductor template layer 104 and the first dielectric layer 106 ) can be formed by methods known to those skilled in the art of the present invention. For example, the above-mentioned nitride semiconductor template layer 104 can be formed by methods such as metalorganic vapor phase epitaxy, molecular beam epitaxy, and the like.

Then, referring to FIG. 1B, patterning the first dielectric layer 106 and the nitride semiconductor template layer 104 in FIG. The last first dielectric layer 106a has a linear, mesh or point distribution pattern.

Next, referring to FIG. 1C , the nitride semiconductor template layer 104 is etched using the patterned first dielectric layer 106 a as an etching mask. At this time, the etched nitride semiconductor template layer 104a will form the same pattern as the first dielectric layer 106a. In addition, the first dielectric layer 106 a and the nitride semiconductor template layer 104 a can also be patterned by using a photoresist layer (not shown) as an etching mask.

Afterwards, referring to FIG. 1D, a second substrate 110 is provided as a supporting substrate. This second substrate 110 includes at least a second base material 112 and a layer of first base material stacked on the second base material 112. Two dielectric layers 114 . Wherein, the material of the second substrate 112 is, for example, sapphire, silicon, GaP, InP, quartz, high temperature resistant glass or ceramic material. The material of the second dielectric layer 114 is, for example, SiO ₂ , Si ₃ N ₄ or spin-on-glass. In addition, after the second substrate 110 is provided, if necessary, the surface of the second dielectric layer 114 can be re-patterned to help the intrusion of the chemical etching solution in the subsequent process.

Then, referring to FIG. 1E , the nitride semiconductor template layer 104 a and the first dielectric layer 106 a of the first substrate 100 are transferred to the second dielectric layer 114 of the second substrate 110 by a bonding transfer process. Wherein, the first dielectric layer 106 a and the second dielectric layer 114 may be bonded first by using a hydrophilic (SC1=H ₂ O—NH ₄ OH—H ₂ O ₂ ) wafer bonding method. Next, the nitride semiconductor template layer 104a is transferred onto the second substrate 110 by physical force. For example: when the material of the first substrate 102 and the second substrate 112 is silicon or sapphire, the step of bond transfer can be directly completed through the difference in thermal expansion coefficient between the materials.

Next, please refer to FIG. 1F, after the above-mentioned bonding transfer process, the nitride semiconductor template layer 104a can be optionally subjected to chemical mechanical polishing (CMP) or reactive ion etching to obtain an epitaxial-level surface (epi-ready) )105, and reduce the defect density.

Next, referring to FIG. 1G, a nitride semiconductor thick film 108 is grown from the nitride semiconductor template layer 104a by using an epitaxial process, wherein the material of the nitride semiconductor thick film 108 includes gallium nitride, aluminum nitride or lattice A material whose constant is close to that of the nitride semiconductor template layer 104a. The above-mentioned epitaxial process is based on the patterned nitride semiconductor template layer 104a, and then performs GaN single crystal lateral bonding and thick film growth. The growth method includes epitaxial processes, including hydride vapor phase epitaxy (HVPE), organic metal vapor phase epitaxy method (MOCVD) or molecular beam epitaxy (MBE).

Then, please refer to FIG. 1H-1 and FIG. 1H-2 , which respectively show different methods for separating the nitride semiconductor thick film 108 from the second substrate 110 .

In FIG. 1H-1, chemical etching is used to remove the bonded first and second dielectric layers 106a, 114 (see FIG. 1G), wherein the chemical etching solution includes hydrofluoric acid (HF) or buffered oxide etching Liquid (Buffered Oxide Etch, BOE); for example, BOE=49%, HF:40% NH ₄ F=1:6. Moreover, if the surface of the second dielectric layer 114 is patterned after the second substrate (as shown in FIG. 1D ) is provided, it will facilitate the intrusion of the chemical etching solution at this time.

In FIG. 1H-2 , mechanical separation is used; for example, a sharp blade 116 is used to separate the nitride semiconductor thick film 108 from the second substrate 110 . In addition, the method of separating the nitride semiconductor thick film 108 and the second substrate 110 can also be to use the chemical etching in FIG. 1H-1 and the mechanical force in this figure alternately at the same time to accelerate the separation. And when the second substrate 112 is quartz or high temperature resistant glass, the second substrate 112 can be directly removed by grinding and chemical etching.

Finally, referring to FIG. 1I , a surface polishing process, such as chemical mechanical polishing (CMP), may be performed on the separated nitride semiconductor thick film 108 .

Fig. 2 is a structural sectional view of a composite material substrate with a pattern structure according to another preferred embodiment of the present invention, which is suitable for making a free standing nitride semiconductor substrate.

Please refer to FIG. 2, the structure of this embodiment includes a substrate 200, a first dielectric layer 202, a second dielectric layer 204 and a nitride semiconductor material 206, wherein the material of the substrate 200 is such as silicon, High temperature resistant materials such as GaP, InP, quartz, glass or ceramic materials. The first dielectric layer 202 is stacked on the surface of the substrate 200, the second dielectric layer 204 is stacked on the surface of the first dielectric layer 202, and the materials of the first and second dielectric layers 202, 204 each independently include SiO ₂ , , Si ₃ N ₄ , spin-on glass or other suitable materials. The nitride semiconductor material 206 is stacked on the surface of the second dielectric layer 204, wherein the material of the nitride semiconductor material 206 includes a semiconductor material containing one of indium (In), aluminum (Al) and gallium (Ga), such as GaN, AlN, InN, AlGaN, InGaN, or AlInN. Moreover, the surface of the nitride semiconductor material 206 has a pattern 208, and the pattern 208 is, for example, a linear pattern, a mesh pattern, a dot pattern or other suitable pattern.

In summary, the present invention is characterized in that the patterned nitride semiconductor template layer is used as a single crystal seed layer to greatly reduce the defect density during subsequent epitaxial growth. In addition, the above-mentioned nitride semiconductor template layer is transferred to the heterogeneous substrate by wafer bonding. In addition, after the epitaxial process, a nitride semiconductor substrate with low defect density can be obtained by self-separation by mechanical force or chemical etching, which is simpler and lower in cost than the prior art.

Although the present invention is disclosed above with preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention, so the protection scope of the present invention What is defined in the claims shall prevail.

Claims (20)

1. A method for manufacturing a nitride semiconductor substrate, comprising: A first substrate is provided, the first substrate includes a first substrate, a nitride semiconductor template layer stacked on the first substrate, and a first dielectric layer stacked on the nitride semiconductor template layer; patterning the first dielectric layer and the nitride semiconductor template layer; providing a second substrate, the second substrate including a second substrate and a second dielectric layer stacked on the second substrate; transferring the nitride semiconductor template layer and the first dielectric layer of the first substrate to the second dielectric layer of the second substrate by a bonding transfer process; growing a nitride semiconductor thick film from the nitride semiconductor template layer using an epitaxial process; and separating the nitride semiconductor thick film from the second substrate. 2. The method for manufacturing a nitride semiconductor substrate according to claim 1, wherein the method for patterning the first dielectric layer and the nitride semiconductor template layer comprises photolithography. 3. The method for manufacturing a nitride semiconductor substrate as claimed in claim 2, wherein the step of patterning the first dielectric layer and the nitride semiconductor template layer comprises: patterning the first dielectric layer; and The nitride semiconductor template layer is etched by using the patterned first dielectric layer as an etching mask. 4. The method for manufacturing a nitride semiconductor substrate as claimed in claim 1, wherein the method for patterning the first dielectric layer and the nitride semiconductor template layer comprises making the first dielectric layer and the nitride semiconductor template layer into Available in linear, mesh or dotted patterns. 5. The method for manufacturing a nitride semiconductor substrate as claimed in claim 1, wherein materials of the first dielectric layer and the second dielectric layer independently comprise SiO ₂ , Si ₃ N ₄ or spin-on-glass. 6. The method for manufacturing a nitride semiconductor substrate as claimed in claim 1, wherein the material of the second substrate comprises sapphire, silicon (Si), GaP, InP, quartz, high temperature resistant glass or ceramic material. 7. The method for manufacturing a nitride semiconductor substrate according to claim 1, wherein the epitaxy process comprises hydride vapor phase epitaxy, metalorganic vapor phase epitaxy or molecular beam epitaxy. 8. The method for manufacturing a nitride semiconductor substrate as claimed in claim 1, wherein the method of separating the nitride semiconductor thick film from the second substrate comprises chemical etching or mechanical force separation. 9. The method of manufacturing a nitride semiconductor substrate as claimed in claim 8, wherein the method of separating the thick nitride semiconductor film from the second substrate comprises using chemical etching and mechanical force alternately at the same time to accelerate the separation. 10. The method for manufacturing a nitride semiconductor substrate as claimed in claim 8, wherein the chemical etching solution comprises HF or a buffered oxide etchant. 11. The method for manufacturing a nitride semiconductor substrate as claimed in claim 1, further comprising patterning the surface of the second dielectric layer after providing the second substrate. 12. The method for manufacturing a nitride semiconductor substrate as claimed in claim 1, wherein the nitride semiconductor template layer of the first substrate and the first dielectric layer are transferred to the second dielectric of the second substrate After forming the layer, chemical mechanical polishing or reactive ion etching is performed on the nitride semiconductor template layer to obtain an epitaxial-level surface. 13. The method for manufacturing a nitride semiconductor substrate as claimed in claim 1, further comprising performing a surface grinding process on the nitride semiconductor thick film after separating the nitride semiconductor thick film from the second substrate. 14. The method of manufacturing a nitride semiconductor substrate according to claim 1, wherein the material of the nitride semiconductor thick film comprises gallium nitride or aluminum nitride. 15. A composite material substrate having a patterned structure, comprising: Substrate; a first dielectric layer stacked on the surface of the substrate; a second dielectric layer stacked on the surface of the first dielectric layer; A nitride semiconductor material stacked on the surface of the second medium is characterized in that: the nitride semiconductor material is a nitride semiconductor material with multiple patterns. 16. The composite material substrate having a patterned structure as claimed in claim 15, wherein the patterns comprise linear, mesh or dot-distributed patterns. 17. The composite material substrate with pattern structure as claimed in claim 15, wherein the material of the substrate comprises sapphire, silicon, GaP, InP, quartz, glass or ceramic material. 18. The composite material substrate with a patterned structure as claimed in claim 15, wherein materials of the first dielectric layer and the second dielectric layer each independently comprise SiO ₂ , Si ₃ N ₄ or spin-on-glass. 19. The composite material substrate with a patterned structure as claimed in claim 15, wherein the nitride semiconductor material comprises a semiconductor material containing at least one of indium, aluminum and gallium. 20. The composite material substrate with a patterned structure as claimed in claim 15, which is suitable for making unsupported nitride semiconductor substrates.

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