TWI727773B - Composite substrate and manufacturing method thereof - Google Patents

Abstract

The invention discloses a composite substrate for growing III-V group material on thereof. The composite substrate includes a substrate, a nucleation layer and a barrier layer. The nucleation layer is disposed on the substrate, and the nucleation layer includes aluminum ions or gallium ions. The barrier layer is disposed between the substrate and the nucleation layer, and the barrier layer has a diffusion barrier property of aluminum ions or gallium ions.

Description

Composite substrate and manufacturing method thereof

The present invention relates to a composite substrate, and particularly relates to a composite substrate used for growing three-five (III-V) materials and a manufacturing method thereof.

In recent years, the application of 5G is in a stage of vigorous development. At present, in the manufacture of 5G wafers, one of the most noticed materials is gallium nitride, which has high frequency, high bandwidth, high efficiency and low loss characteristics. Currently, GaN-based radio frequency components are mainly divided into two technical routes. One is to grow gallium nitride on a semi-insulating silicon carbide substrate, and the other branch is to grow gallium nitride on a silicon substrate. Compared with growing gallium nitride on semi-insulating silicon carbide, growing gallium nitride on a silicon substrate has a cost advantage and is compatible with the current production lines of foundries.

Generally speaking, when growing gallium nitride on a silicon substrate, for example, growing a high electron mobility transistor (HEMT) containing gallium nitride, because gallium reacts with the silicon substrate and consumes silicon atoms. As a result, gallium has an etching-like effect on the silicon substrate. In order to overcome this phenomenon, before the growth of gallium nitride, the first step is to grow on a silicon substrate. Long aluminum nitride to avoid direct growth of gallium nitride on the silicon substrate. However, in the process of forming aluminum nitride, the high temperature of the process tends to cause diffusion effects of certain ions, such as aluminum ions and gallium ions. These ions may diffuse into the silicon substrate, resulting in a decrease in the resistance of the silicon substrate, making the device The efficiency of the radio frequency is lost.

Therefore, there is a need for a new composite substrate and a method for manufacturing the composite substrate.

In various embodiments of the present invention, a composite substrate for growing III-V materials, the composite substrate includes a substrate, a nucleation layer, and a barrier layer. The nucleation layer is arranged on the substrate, and the nucleation layer contains aluminum ions or gallium ions. The barrier layer is arranged between the substrate and the nucleation layer, and the barrier layer has diffusion barrier properties of aluminum ions or gallium ions.

In various embodiments of the present invention, the substrate includes a semi-insulating silicon carbide substrate, a semi-insulating gallium oxide substrate, a silicon-on-insulating substrate, a p-type silicon substrate, an n-type silicon substrate, or a boron nitride substrate.

In various embodiments of the present invention, the barrier layer includes a single layer made of silicon oxide, aluminum oxide, gallium oxide, titanium nitride, or boron nitride, and the single layer has a thickness of 0.1 Å to 1000 Å.

In many embodiments of the present invention, the barrier layer includes a first sublayer and a second sublayer, the second sublayer is located on the first sublayer, and the first sublayer includes silicon oxide, aluminum oxide, or oxide. A single layer made of gallium; and the second sub-layer includes a single layer made of silicon nitride, titanium nitride, or boron nitride.

In various embodiments of the present invention, the first sub-layer has a thickness in the range of 1 Å to 100 Å; and the second sub-layer has a thickness in the range of 1 Å to 100 Å.

In many embodiments of the present invention, the barrier layer includes a first sublayer, a second sublayer, and a third sublayer, the second sublayer is located on the first sublayer, and the third sublayer is located on the second sublayer. The first sub-layer contains a single layer made of silicon oxide, aluminum oxide or gallium oxide; the second sub-layer contains a single layer made of silicon oxide, aluminum oxide, gallium oxide, silicon nitride, titanium nitride or nitride. A single layer made of boron; and the third sub-layer includes a single layer made of silicon nitride, titanium nitride, or boron nitride.

In various embodiments of the present disclosure, the first sub-layer has a thickness of 1 Å to 100 Å; the second sub-layer has a thickness of 1 Å to 100 Å; and the third sub-layer has a thickness of 1 Å to 100 Å.

In many embodiments of the present invention, the nucleation layer includes a single layer made of AlN, GaN, Al _t Ga _1-t N or Al _u In _v Ga _1-uv N, where 0≦t<1 ; 0<u<1;0<v<1; and the nucleation layer has a thickness of 10Å to 10000Å.

In many embodiments of the present invention, the barrier layer has a super lattice structure, which is composed of a first sub-layer and a second sub-layer alternately stacked, wherein the first sub-layer and the second sub-layer are alternately stacked. The layer is selected from the group consisting of AlN, GaN, AlGaN, AlGaInN, silicon oxide, aluminum oxide, gallium oxide, silicon nitride, titanium nitride, or boron nitride, and combinations thereof.

In many embodiments of the present invention, a semiconductor composite substrate includes the composite substrate and III-V group materials. Group III-V materials are arranged on the nucleation layer.

In many embodiments of the present invention, the III-V group material includes gallium nitride, boron nitride, aluminum nitride, indium nitride, aluminum gallium nitride, indium gallium nitride, aluminum indium nitride, Aluminum indium gallium nitride, gallium arsenide or indium phosphide.

In various embodiments of the present invention, a method for manufacturing a composite substrate for growing III-V materials includes the following steps: providing a substrate; using organic metal vapor deposition method, molecular beam epitaxy method, high temperature furnace Tube, chemical vapor deposition or physical vapor deposition to form a barrier layer on the substrate; use organometallic vapor deposition, physical vapor deposition or molecular beam epitaxy to form a nucleation layer on the barrier layer, The nucleation layer contains aluminum ions or gallium ions; and the use of organometallic vapor deposition or molecular beam epitaxy to form III-V materials on the nucleation layer, where the aluminum ions or gallium ions used as the nucleation layer pass through the barrier layer When diffusing to the substrate, the barrier layer traps aluminum ions or gallium ions from the nucleation layer.

In various embodiments of the present invention, the barrier layer includes a single layer made of silicon oxide, aluminum oxide, gallium oxide, titanium nitride, or boron nitride, and the single layer has a thickness of 0.1 Å to 1000 Å.

In various embodiments of the present invention, forming the barrier layer further includes forming a first sub-layer on the substrate, wherein the first sub-layer includes a single layer made of silicon oxide, aluminum oxide or gallium oxide, and the first The sub-layer has a thickness of 1 Å to 100 Å; and a second sub-layer is formed on the first sub-layer, wherein the second sub-layer Containing a single layer made of silicon nitride, titanium nitride, or boron nitride, the second sub-layer has a thickness of 1 Å to 100 Å.

In various embodiments of the present invention, forming the barrier layer further includes forming a third sub-layer on the second sub-layer, wherein the third sub-layer is made of silicon nitride, titanium nitride, or boron nitride The third sub-layer has a thickness of 1 Å to 100 Å.

In many embodiments of the present invention, the barrier layer has a super lattice structure, which is composed of a first sub-layer and a second sub-layer alternately stacked, wherein the first sub-layer and the second sub-layer are alternately stacked. The layer is selected from the group consisting of AlN, GaN, AlGaN, AlGaInN, silicon oxide, aluminum oxide, gallium oxide, silicon nitride, titanium nitride, or boron nitride, and combinations thereof.

Hereinafter, the above description will be described in detail by way of implementation, and a further explanation will be provided for the technical solution of the present invention.

10: substrate

12: Barrier layer

12A: The first sub-layer

12B: The second sub-layer

12C: third sublayer

14: Nucleation layer

16: III-V group materials

100: Composite substrate

M100: method

S102: Operation

S104: Operation

S106: Operation

S108: Operation

In order to make the above and other objectives, features, advantages, and embodiments of the present invention more obvious and understandable, please read the following detailed description and match the corresponding drawings.

Figure 1 shows a composite substrate for growing III-V materials according to some embodiments of the present invention.

2A and 2B illustrate a composite substrate with multiple barrier layers according to some embodiments of the present invention.

FIG. 3 shows a flowchart of a manufacturing method for growing a composite substrate of group III-V materials according to some embodiments of the present invention.

The present invention provides a composite substrate for growing III-V materials. By providing a barrier layer between the substrate and the nucleation layer, the effect of the diffusion of aluminum ions or gallium ions to the substrate can be reduced, and the resistance of the diffused ions to the substrate can be reduced The impact of this, and improve the efficiency of the radio frequency of semiconductor components.

FIG. 1 shows a composite substrate 100 for growing III-V materials according to some embodiments of the present invention. As shown in FIG. 1, the composite substrate 100 includes a substrate 10, a nucleation layer 14 and a barrier layer 12. The nucleation layer 14 is disposed on the substrate 10, and the barrier layer 12 is disposed between the substrate 10 and the nucleation layer 14. The composite substrate 100 is used to grow III-V group materials 16. The III-V group material 16 is provided on the nucleation layer 14.

The substrate 10 may be a single crystal substrate, for example, a silicon substrate. In some embodiments, the substrate 10 is a silicon substrate with high resistance. In a specific embodiment, the resistance of the silicon substrate is greater than 1000 Ω-cm.

In some embodiments, the substrate 10 includes a semi-insulating silicon carbide substrate, a semi-insulating gallium oxide substrate, a silicon on insulation (SOI) substrate, a p-type silicon substrate, an n-type silicon substrate, or a boron nitride substrate.

The nucleation layer 14 is used to grow the III-V group material 16 on the substrate 10. In detail, after the nucleation layer 14 is formed on the substrate 10, any III-V material used to form a semiconductor device can be grown on the nucleation layer 14.

The nucleation layer 14 may be a single crystal or polycrystalline layer. In some embodiments, the nucleation layer 14 includes aluminum ions or gallium ions. In a particular embodiment, the nucleation layer 14 comprises _t Ga _1-t N monolayer or Al _u In _v Ga _1-uv N is made of AlN, GaN, Al, where 0 ≦ t <1; 0 < u <1;0<v<1.

The nucleation layer 14 has a thickness in the range of about 10 Å to about 10000 Å. The preferred thickness is in the range of about 30Å to about 1000Å. Preferred values are about 30Å, 90Å, 120Å, 150Å, 180Å, 210Å, 240Å, 270Å, 300Å, 400Å, 500Å, 600Å, 700Å, 800Å, or 900Å.

The nucleation layer 14 can be formed using an organometallic vapor deposition method, a physical vapor deposition method, a molecular beam epitaxy method, or any other suitable method.

As shown in FIG. 1, after the nucleation layer 14 is formed on the substrate 10, next, the III-V group material 16 is grown on the nucleation layer 14. The III-V group material 16 is disposed on the nucleation layer 14, wherein the III-V group material 16 includes gallium nitride, boron nitride, aluminum nitride, indium nitride, aluminum gallium nitride, indium gallium nitride, and Aluminum indium, aluminum indium gallium nitride, gallium arsenide or indium phosphide.

The III-V group material 16 can be formed using organometallic vapor deposition, molecular beam epitaxy, or any other suitable method. It is worth noting that when the III-V group material 16 is grown on the nucleation layer 14, because the substrate 10 is placed in a high-temperature process environment, such as a thin film growth chamber, aluminum ions or gallium ions in the nucleation layer 14 may be It diffuses from the nucleation layer 14 to surrounding layers, for example, to the substrate 10. The aluminum ions or gallium ions diffused to the substrate 10 will cause the resistance of the substrate 10 to decrease, which in turn causes the performance of the subsequently formed semiconductor device to decrease, for example, the problem of attenuation of radio frequency efficiency.

The present invention provides a composite substrate 100 having a barrier layer 12 between the substrate 10 and the nucleation layer 14 to reduce trivalent ions, such as aluminum ions or gallium ions, diffused from the nucleation layer 14 to the substrate 10 .

In some embodiments, the barrier layer 12 has diffusion barrier properties of aluminum ions or gallium ions. For example, aluminum ions or gallium ions have a lower diffusion coefficient in the barrier layer 12. In some embodiments, the barrier layer 12 includes a single layer made of silicon oxide, aluminum oxide, gallium oxide, titanium nitride, or boron nitride. In some embodiments, the barrier layer 12 substantially covers the substrate 10.

The barrier layer 12 can be formed using a high temperature furnace tube, a chemical vapor deposition method or a physical vapor deposition method or any other suitable method.

The barrier layer 12 has a thickness in the range of about 0.1 Å to about 1000 Å. The preferred thickness is in the range of about 1 Å to about 100 Å. Preferred values are about 5Å, 10Å, 15Å, 20Å, 25Å, 30Å, 50Å, 70Å, 90Å, or 95Å. If the thickness of the barrier layer 12 is too thin, it will not be sufficient to block the diffusion of aluminum ions or gallium ions; if the thickness of the barrier layer 12 is too thick, it will be difficult to subsequently grow single crystals or polycrystals on the barrier layer 12 The nucleation layer 14 and the III-V group material 16 thereon.

It should be noted that the barrier layer 12 can also be a multi-layer structure. The combination of different materials and the combination of different thicknesses for the multi-layer allows the diffusion of trivalent ions to the substrate 10 to be further reduced.

2A and 2B illustrate a composite substrate 100 with multiple barrier layers according to some embodiments of the present invention.

As shown in Figure 2A, the barrier layer 12 has a two-layered multi-layer structure. The barrier layer 12 includes a first sublayer 12A and a second sublayer 12B. The layer 12B is located on the first sub-layer 12A. In some embodiments, the second sublayer 12B substantially covers the first sublayer 12A.

In some embodiments, the first sub-layer 12A includes a single layer made of silicon oxide, aluminum oxide, or gallium oxide.

In some embodiments, the first sub-layer 12A has a thickness in the range of about 1 Å to about 100 Å. Preferred values are about 5Å, 10Å, 15Å, 20Å, 25Å, 30Å, 50Å, 70Å, 90Å, or 95Å.

In some embodiments, the second sub-layer 12B includes a single layer made of silicon nitride, titanium nitride, or boron nitride.

The second sub-layer 12B has a thickness in the range of about 1 Å to about 100 Å. Preferred values are about 5Å, 10Å, 15Å, 20Å, 25Å, 30Å, 50Å, 70Å, 90Å, or 95Å.

As shown in Figure 2B, the barrier layer 12 has a three-layer multi-layer structure. The barrier layer 12 includes a first sub-layer 12A, a second sub-layer 12B, and a third sub-layer 12C. The second sub-layer 12B is located in the first sub-layer 12A, a second sub-layer 12B, and a third sub-layer 12C. On one sub-layer 12A, the third sub-layer 12C is located on the second sub-layer 12B. In some embodiments, the third sublayer 12C substantially covers the second sublayer 12B.

The first sub-layer 12A includes a single layer made of silicon oxide, aluminum oxide, or gallium oxide.

The first sub-layer 12A has a thickness in the range of about 1 Å to about 100 Å. Preferred values are about 5Å, 10Å, 15Å, 20Å, 25Å, 30Å, 50Å, 70Å, 90Å, or 95Å.

The second sub-layer 12B includes a single layer made of silicon oxide, aluminum oxide, gallium oxide, silicon nitride, titanium nitride, or boron nitride.

The second sub-layer 12B has a thickness in the range of about 1 Å to about 100 Å. Preferred values are about 5Å, 10Å, 15Å, 20Å, 25Å, 30Å, 50Å, 70Å, 90Å, or 95Å.

The third sub-layer 12C includes a single layer made of silicon nitride, titanium nitride, or boron nitride.

The third sub-layer 12C has a thickness in the range of about 1 Å to about 100 Å. Preferred values are about 5Å, 10Å, 15Å, 20Å, 25Å, 30Å, 50Å, 70Å, 90Å, or 95Å.

The respective sub-layers 12A, 12B, and 12C of the barrier layer 12 can be formed using a high-temperature furnace tube, a chemical vapor deposition method or a physical vapor deposition method, or any other suitable method.

It is worth noting that the barrier layer 12 may also have a super lattice structure, which is composed of a first sub-layer and a second sub-layer alternately stacked (not shown for simplicity). With the super-crystalline structure of the barrier layer 12, the diffusion of trivalent ions to the substrate 10 can be further reduced.

In some embodiments, the first sublayer and the second sublayer of the barrier layer 12 having a supercrystalline structure are selected from AlN, GaN, AlGaN, AlGaInN, silicon oxide, aluminum oxide, gallium oxide, silicon nitride, and nitride. The group consisting of titanium or boron nitride and combinations thereof.

In some embodiments, metal-organic vapor deposition, molecular beam epitaxy, high-temperature furnace tube, chemical vapor deposition, or physical vapor deposition is used to form the superposition of the first sublayer and the second sublayer alternately stacked. Crystal structure.

In some embodiments, the thickness of the barrier layer 12 having a super-crystalline structure is in the range of about 1 Å to about 200 Å, respectively. Preferred values are about 5Å, 10Å, 20Å, 40Å, 60Å, 80Å, 100Å, 120Å, 140Å, 160Å, 180Å, or 200Å.

FIG. 3 shows a flowchart of a manufacturing method M100 of a composite substrate 100 for growing a III-V group material 16 according to some embodiments of the present invention. The method M100 includes operation S102, operation S104, operation S106, and operation S108.

The method M100 starts in operation S102. Referring to FIG. 1, a substrate 10 is provided. The substrate 10 is a silicon substrate with high resistance. In a specific embodiment, the resistance of the silicon substrate is greater than 1000 Ω-cm.

Then, the method M100 proceeds to operation S104, and referring to FIG. 1, the barrier layer 12 is formed on the substrate 10 by using a high temperature furnace tube, a chemical vapor deposition method or a physical vapor deposition method. In some embodiments, a physical layer deposition method is used to form the barrier layer 12 on the silicon substrate, which is silicon dioxide with a thickness of about 1 nm.

Next, the method M100 proceeds to operation S106, and referring to FIG. 1 continuously, the nucleation layer 14 is formed on the barrier layer 12 by using metal organic vapor deposition, physical vapor deposition, or molecular beam epitaxy. In some embodiments, a physical layer deposition method is used to deposit the nucleation layer 14, which is aluminum nitride with a thickness of about 30 nm. In some embodiments, the nucleation layer 14 is grown by the metal organic vapor deposition method, and the nucleation layer 14 is Al _x Ga _1-x N. The aluminum content of the nucleation layer has a gradient concentration in the direction perpendicular to the substrate 10 , Decreases in the direction away from the substrate 10.

Next, the method M100 proceeds to operation S108, and with continued reference to FIG. 1, the III-V group material 16 is formed on the nucleation layer 14 using the metal organic vapor deposition method or the molecular beam epitaxy method, wherein the aluminum ion of the nucleation layer 14 Or when gallium ions diffuse into the substrate 10 through the barrier layer 12, the barrier layer 12 traps aluminum ions or gallium ions from the nucleation layer 14.

In some embodiments, the III-V group material 16 is a high resistance GaN layer. In some embodiments, the high resistance GaN layer is doped with carbon or iron. In a specific embodiment, the carbon doping concentration is about 1E16 [1/cm3] to about 1E21 [1/cm3]. In a specific embodiment, the iron doping concentration is about 1E16 [1/cm3] to about 1E19 [1/cm3].

In other embodiments, the III-V group material 16 is Al _y Ga _1-y N, where 0.1<y<0.3. In a specific embodiment, the III-V group material 16 is p-GaN or p-Al _z Ga _1-z N.

Referring again to operation S104 and FIG. 2A, in some embodiments, forming the barrier layer 12 includes forming a first sub-layer 12A on the substrate 10 and forming a second sub-layer 12B on the first sub-layer 12A. In other embodiments, referring to FIG. 2B, forming the barrier layer 12 further includes forming a third sub-layer 12C on the second sub-layer 12B.

In summary, a composite substrate for growing III-V materials has a barrier layer arranged between the substrate and the nucleation layer, so as to prevent the ions of the nucleation layer from diffusing to the substrate during the subsequent high temperature process , In order to improve the problem that the resistance of the substrate is attenuated by ion diffusion.

10: substrate

12: Barrier layer

14: Nucleation layer

16: III-V group materials

100: Composite substrate

Claims (15)

A composite substrate, comprising: a substrate; a nucleation layer disposed on the substrate and containing aluminum ions or gallium ions; and a barrier layer disposed between the substrate and the nucleation layer and containing aluminum ions or gallium ions The diffusion barrier properties of ions include: a first sub-layer, including a single layer made of silicon oxide, aluminum oxide or gallium oxide; and a second sub-layer, located on the first sub-layer, including a layer made of nitrogen A single layer made of silicon fluoride, titanium nitride or boron nitride. The composite substrate according to claim 1, wherein the substrate comprises a semi-insulating silicon carbide substrate, a semi-insulating gallium oxide substrate, a silicon-on-insulating substrate, a p-type silicon substrate, an n-type silicon substrate, or a boron nitride substrate. The composite substrate according to claim 1, wherein the barrier layer comprises a single layer made of silicon oxide, aluminum oxide, gallium oxide, titanium nitride, or boron nitride, and the single layer has a thickness of 0.1 Å To the range of 1000Å. The composite substrate according to claim 1, wherein the first sub-layer has a thickness in the range of 1 Å to 100 Å; and the second sub-layer has a thickness in the range of 1 Å to 100 Å. The composite substrate according to claim 1, wherein the barrier layer includes a first sub-layer, a second sub-layer, and a third sub-layer, the second sub-layer is located on the first sub-layer, and the first sub-layer Three sub-layers are located on the second sub-layer, wherein the first sub-layer includes a single layer made of silicon oxide, aluminum oxide or gallium oxide; the second sub-layer includes a single layer made of silicon oxide, aluminum oxide, gallium oxide, A single layer made of silicon nitride, titanium nitride, or boron nitride; and the third sub-layer includes a single layer made of silicon nitride, titanium nitride, or boron nitride. The composite substrate according to claim 5, wherein the first sublayer has a thickness in the range of 1Å to 100Å; the second sublayer has a thickness in the range of 1Å to 100Å; and the third sublayer The layer has a thickness in the range of 1 Å to 100 Å. The composite substrate according to claim 1, wherein the nucleation layer comprises a single layer made of AlN, GaN, Al _t Ga _1-t N or Al _u In _v Ga _1-uv N, wherein 0≦t<1;0<u<1;0<v<1; and the nucleation layer has a thickness in the range of 10Å to 10000Å. The composite substrate according to claim 1, wherein the barrier layer has a super lattice structure, which is composed of a first sublayer and a second sublayer alternately stacked, wherein the first sublayer And the second sublayer is selected from AlN, GaN, AlGaN, AlGaInN, silicon oxide, aluminum oxide, gallium oxide, silicon nitride, titanium nitride or boron nitride and combinations thereof The group formed. A semiconductor composite substrate, comprising: the composite substrate according to any one of claims 1 to 6; and a III-V group material disposed on the nucleation layer. The semiconductor composite substrate according to claim 9, wherein the III-V group material includes gallium nitride, boron nitride, aluminum nitride, indium nitride, aluminum gallium nitride, indium gallium nitride, aluminum indium nitride, Aluminum indium gallium nitride, gallium arsenide or indium phosphide. A method for manufacturing a composite substrate includes: providing a substrate; forming a barrier layer on the substrate using metal organic vapor deposition, molecular beam epitaxy, high temperature furnace tube, chemical vapor deposition, or physical vapor deposition Above, wherein the barrier layer formed includes forming a first sub-layer on the substrate, the first sub-layer including a single layer made of silicon oxide, aluminum oxide or gallium oxide, and forming a second sub-layer The layer is on the first sub-layer, and the second sub-layer includes a single layer made of silicon oxide, aluminum oxide, gallium oxide, silicon nitride, titanium nitride, or boron nitride; an organometallic vapor deposition method is used , Physical vapor deposition or molecular beam epitaxy to form a nucleation layer on the barrier layer, the nucleation layer containing aluminum ions or gallium ions; and Use organometal vapor deposition or molecular beam epitaxy to form a III-V material on the nucleation layer, wherein when the aluminum ions or gallium ions of the nucleation layer diffuse to the substrate through the barrier layer, The barrier layer traps aluminum ions or gallium ions from the nucleation layer. The manufacturing method according to claim 11, wherein the barrier layer comprises a single layer made of silicon oxide, aluminum oxide, gallium oxide, titanium nitride, or boron nitride, and the single layer has a thickness of 0.1 Å to 1000Å. The manufacturing method according to claim 11, wherein the first sub-layer has a thickness of 1 Å to 100 Å, and the second sub-layer has a thickness of 1 Å to 100 Å. The manufacturing method according to claim 13, wherein forming the barrier layer further comprises: forming a third sublayer on the second sublayer, wherein the third sublayer includes silicon nitride, titanium nitride, or nitrogen. A single layer made of boron oxide, the third sub-layer has a thickness of 1 Å to 100 Å. The manufacturing method according to claim 11, wherein the barrier layer has a super lattice structure composed of a first sublayer and a second sublayer alternately stacked, wherein the first sublayer The layer and the second sub-layer are selected from AlN, GaN, AlGaN, AlGaInN, silicon oxide, aluminum oxide, gallium oxide, silicon nitride, titanium nitride or boron nitride and The group formed by the combination.

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