Substrate, epitaxial wafer and growth method thereof
阅读说明：本技术 一种衬底、外延片及其生长方法 (Substrate, epitaxial wafer and growth method thereof ) 是由 张志荣 郭艳敏 尹甲运 王波 高楠 房玉龙 冯志红 于 2019-10-31 设计创作，主要内容包括：本发明涉及半导体技术领域,具体公开一种衬底、外延片及其生长方法。所述衬底,包括：晶片,所述晶片上外延B<Sub>x</Sub>Al<Sub>1-x</Sub>N薄膜层,所述B<Sub>x</Sub>Al<Sub>1-</Sub><Sub>x</Sub>N薄膜层的厚度为1-2000nm。所述外延片为基于上述衬底制备的氮化物外延材料。本申请通过在晶片上外延B<Sub>x</Sub>Al<Sub>1-x</Sub>N薄膜形成BAlN复合衬底,然后在BAlN复合衬底上外延生长氮化物薄膜,由于B元素与氮化物晶格匹配,且BN晶格具有的滑移特性,降低氮化物外延薄膜的位错密度和应力,提高了氮化物外延材料的晶体质量。(The invention relates to the technical field of semiconductors, and particularly discloses a substrate, an epitaxial wafer and a growth method of the epitaxial wafer. The substrate includes: wafer on which B is epitaxial x Al 1‑x N thin film layer, B x Al 1‑ x The thickness of the N thin film layer is 1-2000 nm. The epitaxial wafer is a nitride epitaxial material prepared on the basis of the substrate. The present application is achieved by epitaxy of B on a wafer x Al 1‑x The N film forms a BALN composite substrate, and then a nitride film is epitaxially grown on the BALN composite substrate, and due to the fact that B elements are matched with nitride lattices and the BN lattices have the slip characteristics, the dislocation density and the stress of the nitride epitaxial film are reduced, and the crystal quality of the nitride epitaxial material is improved.)
1. A substrate, characterized by: the method comprises the following steps:
wafer on which B is epitaxialxAl1-xN thin film layer, BxAl1-xThe thickness of the N thin film layer is 1-2000 nm.
2. The substrate of claim 1, wherein: b isxAl1-xThe thickness of the N thin film layer is 1-200 nm.
3. The substrate of claim 2, wherein: b isxAl1-xThe thickness of the N thin film layer is 10-50 nm.
4. The substrate of claim 1, wherein:b isxAl1-xX in the N thin film layer is 0.01-1.
5. The substrate of claim 4, wherein: b isxAl1-xX in the N thin film layer is 0.1-0.2.
6. The substrate of claim 1, wherein: the wafer is gallium nitride, sapphire, silicon carbide, silicon, aluminum nitride, silicon dioxide, diamond or graphite.
7. The substrate of any one of claims 1-6, wherein: b isxAl1-xThe preparation method of the N thin film layer comprises thermal evaporation, pulsed laser deposition, ion beam assisted deposition, electron beam evaporation, magnetron sputtering, plasma enhanced chemical vapor deposition, microwave plasma or microwave electron cyclotron resonance.
8. The substrate of claim 7, wherein: the conditions of the magnetron sputtering method are as follows: the magnetron sputtering power is 100W-200W, the target distance is 0.2cm-2cm, the sputtering time is 10min-60min, and the sputtering temperature is 0 ℃ to 300 ℃.
9. An epitaxial wafer characterized by a nitride epitaxial material prepared on the basis of the substrate according to any one of claims 1 to 6.
10. A method for growing an epitaxial wafer, comprising:
growth of B on wafers by magnetron sputteringxAl1-xAn N thin film layer;
will grow BxAl1-xAnd putting the wafer of the N thin film layer serving as a composite substrate into the reaction cavity, and growing the nitride epitaxial material.
Technical Field
The invention relates to the technical field of semiconductors, in particular to a substrate, an epitaxial wafer and a growth method thereof.
Background
Third generation semiconductor nitride materials, represented by gallium nitride, have been the focus of research in the semiconductor field due to their wide forbidden bandwidth, high electron velocity, and other characteristics. In particular, gallium nitride-based devices are widely applied to electronic systems such as wireless communication, radar and the like in microwave and millimeter wave frequency bands, and have very wide development prospects in the fields of photoelectrons and microelectronics.
Gallium nitride epitaxial materials are mainly obtained by epitaxial growth on substrates, including gallium nitride, sapphire, silicon carbide, aluminum nitride, or silicon-based substrates, and the like. However, due to the problems of larger lattice mismatch and thermal expansion mismatch between the gallium nitride material and the substrate, such as a mismatch ratio with sapphire of 16%, a mismatch ratio with silicon carbide of 3.4%, and a mismatch ratio with silicon substrate of 17%, a large amount of dislocations and defects are introduced into the epitaxially grown gallium nitride material, and the defect density is as high as 108--2Meanwhile, great stress is generated, and the service life and the service efficiency of the gallium nitride-based device are seriously influenced.
The existing growing method of the gallium nitride epitaxial material is a two-step method, namely, a layer of nitride nucleation layer grows on a substrate at first, and then the gallium nitride epitaxial material grows on the nucleation layer after annealing crystallization at a high temperature continuously. Due to the fact that defects and stress are generated due to the fact that lattice and thermal expansion mismatch between the substrate and the GaN thin film, the crystal quality of the GaN gallium nitride epitaxial material is poor, and the application of the GaN gallium nitride material is serious.
Disclosure of Invention
The invention provides a substrate aiming at the problems of lattice mismatch and thermal expansion mismatch between the conventional substrate and a GaN thin film.
And an epitaxial wafer prepared based on the substrate.
And a method for growing the epitaxial wafer.
A first aspect of an embodiment of the present invention provides a substrate, including:
wafer on which B is epitaxialxAl1-xN thin film layer, BxAl1-xThe thickness of the N thin film layer is 1-2000 nm.
Optionally, B isxAl1-xThe thickness of the N thin film layer is 1-200 nm.
Optionally, B isxAl1-xThe thickness of the N thin film layer is 10-50 nm.
Optionally, B isxAl1-xX in the N thin film layer is 0.01-1.
Optionally, B isxAl1-xX in the N thin film layer is 0.1-0.2.
Optionally, the wafer is gallium nitride, sapphire, silicon carbide, silicon, aluminum nitride, silicon dioxide, diamond or graphite.
Optionally, B isxAl1-xThe preparation method of the N thin film layer comprises thermal evaporation, pulsed laser deposition, ion beam assisted deposition, electron beam evaporation, magnetron sputtering, plasma enhanced chemical vapor deposition, microwave plasma or microwave electron cyclotron resonance.
Optionally, the magnetron sputtering method has the following conditions: the magnetron sputtering power is 100W-200W, the target distance is 0.2cm-2cm, the sputtering time is 10min-60min, and the sputtering temperature is 0 ℃ to 300 ℃.
A second aspect of embodiments of the present invention provides an epitaxial wafer including a nitride epitaxial material prepared by using the substrate according to any one of the first aspect of embodiments of the present invention.
The present application epitaxially structures B of quasi-hexagonal structure on a waferxAl1-xN thin film layer, BxAl1-xN has small bonding force in the c-axis direction and is easy to slide between layers, so that BxAl1-xN and the wafer form a BAlN composite substrate; the lattice matching of the BAlN composite substrate and the nitride epitaxial material can also reduce the dislocation density, avoid the phase separation of B in the growth process of the epitaxial material and be beneficial to the growth of the nitride material.
A third aspect of an embodiment of the present invention provides a method for growing an epitaxial wafer, including:
growth of B on wafers by magnetron sputteringxAl1-xAn N thin film layer;
will grow BxAl1-xAnd putting the wafer of the N thin film layer serving as a composite substrate into the reaction cavity, and growing the nitride epitaxial material.
Wherein the nitride material is AlN, GaN or InN.
Wherein the nitride material is an alloy structure of Ga, Al and In.
The present application is achieved by epitaxy of B on a waferxAl1-xThe N film forms a BALN composite substrate, and then a nitride film is epitaxially grown on the BALN composite substrate, and due to the fact that B elements are matched with nitride lattices and the BN lattices have the slip characteristics, the dislocation density and the stress of the nitride epitaxial film are reduced, and the crystal quality of the nitride epitaxial material is improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic view of a wafer provided in example 1 of the present invention;
100, a wafer; 200. b isxAl1-xAn N thin film layer; 300. a substrate.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
In one embodiment, referring to fig. 1, the present embodiment provides a
In the above-mentioned inclusion BxAl1-xAnd carrying out epitaxial growth of nitride epitaxial materials on the BAlN composite substrate of the N thin film layer.
Wherein the magnetron sputtering method comprises the following conditions: the magnetron sputtering power is 150W, the target distance is 1cm, the sputtering time is 30min, the sputtering temperature is 300 DEG C
In one embodiment, referring to fig. 1, the present embodiment provides a
In the above-mentioned inclusion BxAl1-xAnd carrying out epitaxial growth of nitride epitaxial materials on the BAlN composite substrate of the N thin film layer.
Wherein the magnetron sputtering method comprises the following conditions: the magnetron sputtering power is 100W, the target distance is 0.2cm, the sputtering time is 60min, and the sputtering temperature is 10 ℃.
In one embodiment, referring to fig. 1, the present embodiment provides a
In the above-mentioned inclusion BxAl1-xAnd carrying out epitaxial growth of nitride epitaxial materials on the BAlN composite substrate of the N thin film layer.
Wherein the magnetron sputtering method comprises the following conditions: the magnetron sputtering power is 200W, the target distance is 2cm, the sputtering time is 10min, and the sputtering temperature is 200 ℃.
One isIn an embodiment, referring to fig. 1, the embodiment provides a
In the above-mentioned inclusion BxAl1-xAnd carrying out epitaxial growth of nitride epitaxial materials on the BAlN composite substrate of the N thin film layer.
Wherein the magnetron sputtering method comprises the following conditions: magnetron sputtering power of 130W, target distance of 0.5cm, sputtering time of 40min and sputtering temperature of 100 ℃.
In one embodiment, referring to fig. 1, the present embodiment provides a
In the above-mentioned inclusion BxAl1-xAnd carrying out epitaxial growth of nitride epitaxial materials on the BAlN composite substrate of the N thin film layer.
Wherein the magnetron sputtering method comprises the following conditions: the magnetron sputtering power is 170W, the target distance is 0.2cm, the sputtering time is 10min, and the sputtering temperature is 0 ℃.
In one embodiment, any of the above BAlN composite substrates is selected for use in epitaxial growth for preparing nitride epitaxial materials.
In one embodiment, any of the above BAlN composite substrates is selected for epitaxial growth for preparing a nitride epitaxial material, and the growth method comprises the following steps: growth of B on wafers by magnetron sputteringxAl1-xAn N thin film layer; will grow BxAl1-xWafer of N thin film layer asAnd placing the composite substrate into a reaction chamber, and growing a nitride epitaxial material.
In one embodiment, the growth process of the nitride epitaxial material is as follows: controlling the temperature at 500-600 ℃, and growing a nucleation layer with the thickness of 0.01-1000nm on the BALN composite substrate; the nitride material is then grown at 1000 c.
In one embodiment, the growth process of the nitride epitaxial material is as follows: controlling the temperature to be 1000 ℃, and directly growing the nitride material on the BALN composite substrate.
Before epitaxial growth, the BAlN composite substrate is placed in a reaction cavity for surface treatment, and the surface treatment conditions of the BAlN composite substrate are as follows: the temperature of the hydrogen atmosphere is 400-1200 ℃.
Before epitaxial growth, the BAlN composite substrate is placed in a reaction cavity for surface treatment, and the surface treatment conditions of the BAlN composite substrate are as follows: the mixed gas atmosphere of hydrogen and nitrogen is 400-1200 ℃.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.
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