Silicon carbide coated silicon-molybdenum composite structure substrate tray

Abstract

The invention relates to the technical field of semiconductor materials, in particular to a silicon carbide coated silicon-molybdenum composite structure substrate tray which comprises a single-face polished silicon wafer, a molybdenum tray and a molybdenum clamp. The single-side polished silicon wafer comprises an upper surface and a lower surface, the flatness RMS of the lower surface is smaller than 0.5 nm, and the flatness RMS of the upper surface is larger than 200 nm; the top surface of the molybdenum tray is tightly attached to the lower surface of the single-sided polished silicon wafer; the bottom surface of the molybdenum tray is matched with the molybdenum hoop; a single-face polished silicon wafer capable of efficiently absorbing infrared band radiation is inserted into a molybdenum tray, so that energy loss is reduced, and efficient heat absorption is realized; the top surface of the single-sided polished silicon wafer is designed to be a rough surface, so that the reflection of infrared radiation is reduced; the bottom surface of the single-sided polished silicon wafer is designed as a polished surface, so that the heat conduction performance is enhanced; silicon carbide film layers are plated on the surfaces of all the structures to serve as protective layers, and the service life of the substrate tray under the high-temperature oxygen-enriched condition can be effectively prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor materials, and particularly relates to a silicon carbide-coated silicon-molybdenum composite structure substrate tray. Background Art

[0002] Semiconductor materials, as the cornerstone for fabricating power electronic devices and optoelectronic devices, are strategic key materials that various countries are competing to seize in the current development of informatization and intelligence.

[0003] Among various growth processes of semiconductor materials, molecular beam epitaxy (MBE) has advantages such as a pure growth environment and easy control of the epitaxial growth rate. Therefore, it is an ideal process choice for preparing high-quality semiconductor materials.

[0004] During the epitaxial growth process, substrates such as sapphire, gallium nitride, and gallium oxide, which are commonly selected, have very low thermal conductivities. This makes the efficiency of heat conduction from the tray to the growth surface through the substrate very low, and the temperature uniformity is poor, which is not conducive to the precise control of the temperature field during the material epitaxial process. As a result, it is difficult to obtain high-quality semiconductor thin film materials.

[0005] To achieve high-quality semiconductor thin film epitaxy, it is necessary to precisely control the surface temperature of the substrate wafer. Therefore, the requirements for the substrate wafer tray are as follows: 1. It can absorb heat efficiently and improve the heating efficiency of the substrate wafer; 2. It can conduct heat uniformly to achieve a uniform thermal field distribution on the surface of the substrate wafer; 3. It can have good use stability in a high-temperature atmosphere rich in active gases such as oxygen and nitric oxide.

[0006] Existing substrate wafer trays are usually solid molybdenum trays, which have a low infrared absorption rate. Therefore, their heating efficiency is low, and high-power heating output is required to maintain the surface temperature of the substrate wafer. Summary of the Invention

[0007] In view of this, the present invention aims to provide a substrate tray with a novel structure of silicon carbide-coated silicon-molybdenum composite structure, which can improve the substrate heating efficiency and temperature uniformity during the epitaxial process, reduce the thermal loss during equipment operation, and improve the epitaxial quality of semiconductor materials.

[0008] To achieve the above object, the technical solution of the present invention is realized as follows: A silicon carbide-coated silicon-molybdenum composite structure substrate tray, which includes a single-side polished silicon wafer, a molybdenum tray, and a molybdenum clamp; The single-side polished silicon wafer includes an upper surface and a lower surface, the flatness RMS of the lower surface is less than 0.5 nm, and the flatness RMS of the upper surface is greater than 200 nm; The molybdenum tray includes a top surface and a bottom surface; The top surface of the molybdenum tray is closely attached to the lower surface of the single-sided polished silicon wafer; The bottom surface of the molybdenum tray is cooperatively arranged with the molybdenum clamp.

[0009] Furthermore, the thickness of the single-sided polished silicon wafer is 500 μm, and the resistivity of the single-sided polished silicon wafer is less than 0.01 Ω·cm.

[0010] Furthermore, a silicon carbide film layer is plated on the single-sided polished silicon wafer.

[0011] Furthermore, a silicon carbide film layer is plated on the molybdenum tray.

[0012] Furthermore, a silicon carbide film layer is plated on the molybdenum clamp.

[0013] Furthermore, the thickness of the silicon carbide film layer is 0.5 μm to 3 μm, the film thickness uniformity of the silicon carbide film layer is better than 2%, and the flatness RMS of the silicon carbide film layer is less than 0.8 nm.

[0014] Furthermore, the adhesion of the silicon carbide film layer is better than 100 mN.

[0015] Furthermore, the preparation method of the silicon carbide film layer includes: Using argon as the working gas for magnetron sputtering, the sputtering gas pressure of the magnetron sputtering is 0.6 Pa to 2.5 Pa, the sputtering power of the magnetron sputtering is 800 W to 1800 W. After sputtering, annealing is performed at a temperature range of 800 °C to 1200 °C for 0.5 h to 2 h to obtain the silicon carbide film layer.

[0016] Furthermore, the outer periphery of the molybdenum tray is provided with protruding tentacles, the width of the protruding tentacles is 2 mm to 4 mm, and the length of the protruding tentacles is 3 mm to 5 mm.

[0017] Furthermore, the bottom surface of the molybdenum tray includes an annular recessed groove, the molybdenum clamp is a horseshoe-shaped molybdenum spring retaining ring, and the molybdenum clamp is embedded in the molybdenum tray.

[0018] Compared with the prior art, the present invention can achieve the following beneficial effects: The present invention provides a silicon carbide-coated silicon-molybdenum composite structure substrate tray with a novel structure. Creatively, a single-sided polished silicon wafer capable of efficiently absorbing infrared band radiation is inserted into the molybdenum tray to reduce energy loss and achieve high-efficiency heat absorption. At the same time, the top surface of the single-sided polished silicon wafer is designed to be a rough surface, thereby reducing the reflection of infrared radiation and enhancing its absorption characteristics. The bottom surface of the single-sided polished silicon wafer is designed to be a polished surface, so as to form a tight fit with the molybdenum tray and enhance the heat conduction performance. In addition, in a further preferred embodiment of the present invention, a silicon carbide film layer is coated on all structural surfaces as a protective layer, which can effectively prevent the thermal oxidation problem of the substrate tray and improve the service life of the substrate tray under high-temperature oxygen-rich conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 It is a schematic structural diagram of the silicon carbide-coated silicon-molybdenum composite structure substrate tray described in the embodiment of the present invention.

[0020] DESCRIPTION OF THE REFERENCE NUMERALS: 1. Single-sided polished silicon wafer; 2. Molybdenum tray; 3. Substrate wafer; 4. Molybdenum clamp. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0022] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0023] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0024] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific circumstances.

[0025] The specific embodiment of the present invention provides a silicon carbide-coated silicon-molybdenum composite structure substrate tray. The silicon carbide-coated silicon-molybdenum composite structure substrate tray includes a single-side polished silicon wafer, a molybdenum tray, and a molybdenum clamp; the single-side polished silicon wafer includes an upper surface and a lower surface. The lower surface is a polished surface, and the flatness RMS (Root Mean Square, which is an index for calculating the data distribution by squaring a set of data, calculating the average value, and then taking the square root) of the lower surface is less than 0.5 nm. The upper surface is a rough surface, and the flatness RMS of the upper surface is greater than 200 nm; the thickness of the single-side polished silicon wafer is 500 μm, and the resistivity of the single-side polished silicon wafer is less than 0.01 Ω·cm; the setting of the single-side polished silicon wafer improves the overall heat absorption efficiency of the substrate tray, and further improves the overall heating performance of the substrate tray. The molybdenum tray includes a top surface and a bottom surface; the top surface of the molybdenum tray is closely attached to the lower surface of the silicon wafer to enhance the heat conduction performance; the bottom surface of the molybdenum tray is cooperatively arranged with the molybdenum clamp for fixing the substrate wafer.

[0026] In a specific embodiment, a silicon carbide film layer is deposited on the single-sided polished silicon wafer, a silicon carbide film layer is deposited on the molybdenum tray, and a silicon carbide film layer is deposited on the molybdenum clamp; in the most preferred solution, a silicon carbide film layer is deposited on all of the single-sided polished silicon wafer, the molybdenum tray, and the molybdenum clamp, which is used for oxygen isolation in a high-temperature environment and can better improve the passivation performance; specifically, a silicon carbide film layer is deposited on the upper surface of the single-sided polished silicon wafer, a silicon carbide film layer is deposited on the top surface of the molybdenum tray, and a silicon carbide film layer is deposited on the surface of the molybdenum clamp.

[0027] In a specific embodiment, the thickness of the silicon carbide film layer is 0.5 μm to 3 μm, the film thickness uniformity of the silicon carbide film layer is better than 2%, and the flatness RMS of the silicon carbide film layer is less than 0.8 nm. The adhesion between the silicon carbide film layer and the single-sided polished silicon wafer, the molybdenum tray, or the molybdenum clamp is better than 100 mN; usually, after 20 hours of MBE epitaxial growth, the silicon wafer surface has an oxide layer with a thickness of about 130 nm; in the technical solution of the present invention, similarly after 20 hours of MBE epitaxial growth, no obvious oxidation is seen on the surface of the single-sided polished silicon wafer coated with the silicon carbide film layer; this fully shows that after depositing the silicon carbide film layer on all of the single-sided polished silicon wafer, the molybdenum tray, and the molybdenum clamp, the passivation performance can be effectively improved.

[0028] In a specific embodiment, a magnetron sputtering technique is used, combined with a high-temperature annealing process to prepare a silicon carbide coating on the surfaces of the molybdenum tray, the single-sided polished silicon wafer, or the molybdenum clamp; specifically, the preparation method of the silicon carbide film layer includes: using argon as the working gas for magnetron sputtering, the sputtering gas pressure of the magnetron sputtering is 0.6 Pa to 2.5 Pa, the sputtering power of the magnetron sputtering is 800 W to 1800 W, and the distance between the target and the molybdenum tray, the single-sided polished silicon wafer, or the molybdenum clamp is 5 cm to 10 cm; after sputtering, annealing is carried out in the temperature range of 800 °C to 1200 °C for 0.5 h to 2 h to obtain the silicon carbide film layer. In a specific embodiment, the top surface of the molybdenum tray is in close contact with the lower surface of the single-sided polished silicon wafer. The outer periphery of the molybdenum tray is provided with protruding antennae for the transfer and fixation of the sample tray. For different substrate manipulators, the number and shape of the protruding antennae are different; the antennae can be absent, or can be 1, 2, 3, 4, 5, 6, 7, etc.; specifically, the protruding antennae can be three, serving as a connection and fixation device matching the substrate manipulator during MBE epitaxial growth; specifically, the protruding antennae can be rectangular small blocks protruding outward. The width of the protruding antennae is 2 mm to 4 mm, and the length of the protruding antennae is 3 mm to 5 mm. The bottom surface of the molybdenum tray includes an annular recessed groove. The molybdenum clamp is a horseshoe-shaped molybdenum spring retaining ring, and the molybdenum clamp is embedded in the molybdenum tray, that is, the size of the horseshoe-shaped molybdenum spring retaining ring just fits into the annular inner groove of the molybdenum tray for fixing the substrate wafer.

[0029] The novel-structured silicon carbide-coated silicon-molybdenum composite substrate tray provided by the specific embodiment of the present invention creatively inserts a single-sided polished silicon wafer capable of efficiently absorbing infrared-band radiation into the molybdenum tray, reducing energy loss and achieving high-efficiency heat absorption; at the same time, the top surface of the single-sided polished silicon wafer is designed to be a rough surface, thereby reducing the reflection of infrared radiation and enhancing its absorption characteristics; the bottom surface of the single-sided polished silicon wafer is designed to be a polished surface, so as to form a close fit with the molybdenum tray and enhance the heat conduction performance; in addition, in a further preferred embodiment of the present invention, a silicon carbide film layer is plated on all structural surfaces as a protective layer, which can effectively prevent the thermal oxidation problem of the substrate tray and improve the service life of the substrate tray under high-temperature and oxygen-rich conditions.

[0030] The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0031] Such as Figure 1As shown in the figure, it is a schematic structural diagram of a silicon carbide-coated silicon-molybdenum composite structure substrate tray according to an embodiment of the present invention. It can be seen from the figure that the structure of the substrate tray in this embodiment includes a single-sided polished silicon wafer 1, a molybdenum tray 2, and a molybdenum clamp 4; the single-sided polished silicon wafer 1 includes an upper surface and a lower surface. The lower surface is the polished surface, and the flatness of the lower surface is less than 0.5 nm. The upper surface is the rough surface, and the flatness of the upper surface is greater than 200 nm; the thickness of the single-sided polished silicon wafer 1 is 500 μm, and the resistivity of the single-sided polished silicon wafer 1 is less than 0.01 Ω·cm; the setting of the single-sided polished silicon wafer 1 improves the overall heat absorption efficiency of the substrate tray, and further improves the overall heating performance of the substrate tray; the molybdenum tray 2 includes a top surface and a bottom surface; the top surface of the molybdenum tray 2 is closely attached to the lower surface of the single-sided polished silicon wafer 1 to enhance the conduction performance; the bottom surface of the molybdenum tray 2 is cooperatively arranged with the molybdenum clamp 4 for fixing the substrate wafer, that is, the substrate wafer 3; three protruding tentacles are provided on the outer periphery of the molybdenum tray 2 for the transfer and fixation of the sample tray. The width of each protruding tentacle is 2 mm to 4 mm, and the length is 3 mm to 5 mm; the bottom surface of the molybdenum tray 2 includes an annular recessed groove, and the molybdenum clamp 4 is a horseshoe-shaped molybdenum spring retaining ring. The size of the horseshoe-shaped molybdenum spring retaining ring just fits into the annular inner groove of the molybdenum tray 2 for fixing the substrate wafer 3; the surfaces of the single-sided polished silicon wafer 1, the molybdenum tray 2, and the molybdenum clamp 4 are all coated with a silicon carbide film layer; the thickness of the silicon carbide film layer is 0.5 μm to 3 μm, the film thickness uniformity of the silicon carbide film layer is better than 2%, and the flatness of the silicon carbide film layer is less than 0.8 nm; the bonding force of the silicon carbide film layer with the single-sided polished silicon wafer 1, the molybdenum tray 2, and the molybdenum clamp 4 is better than 100 mN. The preparation method of the silicon carbide film layer includes: using argon as the working gas for magnetron sputtering, the sputtering pressure of the magnetron sputtering is 0.6 Pa to 2.5 Pa, the sputtering power of the magnetron sputtering is 800 W to 1800 W. After sputtering, annealing is carried out at a temperature range of 800 °C to 1200 °C for 0.5 h to 2 h to obtain the silicon carbide film layer.

[0032] Test results Taking the same set temperature of 600 °C as an example, in the prior art, the substrate temperature of the ordinary tray is about 565 °C, while the substrate temperature in the silicon carbide-coated silicon-molybdenum composite structure substrate tray provided by the embodiment of the present invention is about 580 °C; it fully shows that the silicon carbide-coated silicon-molybdenum composite structure substrate tray provided by the embodiment of the present invention effectively improves the heating efficiency as a whole by setting a single-sided polished silicon wafer with high absorption efficiency in the infrared band.

[0033] In addition, compared with the epitaxial thin film grown using the original ordinary substrate tray, both the film thickness uniformity and the full width at half maximum of the XRD diffraction peak of the epitaxial thin film grown using the silicon-molybdenum composite structure substrate tray coated with silicon carbide provided in the embodiment of the present invention are improved; it fully shows that the silicon-molybdenum composite structure substrate tray coated with silicon carbide provided in the embodiment of the present invention has better uniform heat conduction performance.

[0034] It should be understood that various forms of the processes shown above can be used, and steps can be reordered, added, or deleted. For example, the steps recited in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and no limitation is made herein.

[0035] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A silicon carbide coated silicon-molybdenum composite structure substrate tray, characterized in that: The silicon carbide coated silicon-molybdenum composite structure substrate tray comprises a single-sided polished silicon wafer, a molybdenum tray and a molybdenum clamp; The single-sided polished silicon wafer comprises an upper surface and a lower surface, the flatness RMS of the lower surface is less than 0.5 nm, and the flatness RMS of the upper surface is greater than 200 nm; The molybdenum tray comprises a top surface and a bottom surface; The top surface of the molybdenum tray is tightly fitted to the lower surface of the single-sided polished silicon wafer; The bottom surface of the molybdenum tray is matched with the molybdenum clamp.

2. The silicon carbide coated silicon-molybdenum composite structure substrate tray according to claim 1, characterized in that: The thickness of the single-side polished silicon wafer is 500 μm, and the resistivity of the single-side polished silicon wafer is less than 0.01 Ω·cm.

3. The silicon carbide coated silicon-molybdenum composite structure substrate tray according to claim 1, characterized in that: The single-sided polished silicon wafer is plated with a silicon carbide film layer.

4. The silicon carbide coated silicon-molybdenum composite structure substrate tray according to claim 1, characterized in that: The molybdenum tray is plated with a silicon carbide film layer.

5. The silicon carbide coated silicon-molybdenum composite structure substrate tray according to claim 1, characterized in that: The molybdenum clamp is plated with a silicon carbide film layer.

6. The silicon carbide coated silicon-molybdenum composite structure substrate tray according to any one of claims 3 to 5, characterized in that: The thickness of the silicon carbide film layer is 0.5 μm to 3 μm, the film thickness uniformity of the silicon carbide film layer is better than 2%, and the flatness RMS of the silicon carbide film layer is less than 0.8 nm.

7. The silicon carbide coated silicon-molybdenum composite structure substrate tray according to any one of claims 3 to 5, characterized in that: The bonding force of the silicon carbide film layer is better than 100 mN.

8. The silicon carbide coated silicon-molybdenum composite structure substrate tray according to any one of claims 3 to 5, characterized in that: The method for preparing the silicon carbide film layer comprises: Argon is used as a working gas for magnetron sputtering, the sputtering gas pressure of the magnetron sputtering is 0.6Pa~2.5Pa, the sputtering power of the magnetron sputtering is 800W~1800W, and after sputtering, annealing is performed at a temperature range of 800℃~1200℃ for 0.5h~2h to obtain the silicon carbide film layer.

9. The silicon carbide coated silicon-molybdenum composite structure substrate tray according to claim 1, characterized in that: The outer periphery of the molybdenum tray is provided with protruding feelers, the width of the protruding feelers is 2mm-4mm, and the length of the protruding feelers is 3mm-5mm.

10. The silicon carbide coated silicon-molybdenum composite structure substrate tray according to claim 1, characterized in that: The bottom surface of the molybdenum tray comprises an annular sunken groove, the molybdenum clamp is a horseshoe-shaped molybdenum retaining ring, and the molybdenum clamp is embedded in the molybdenum tray.

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