WO2020088233A1

WO2020088233A1 - Silicon carbide single-crystal growth device without bonding seed crystals

Info

Publication number: WO2020088233A1
Application number: PCT/CN2019/111084
Authority: WO
Inventors: 陈泽斌; 张洁; 廖弘基; 陈华荣
Original assignee: 福建北电新材料科技有限公司
Priority date: 2018-10-31
Filing date: 2019-10-14
Publication date: 2020-05-07
Also published as: CN109234810A

Abstract

A silicon carbide single-crystal growth device without bonding seed crystals, comprising a seed crystal box and a crucible. The crucible is internally provided with a shelf layer. The seed crystal box is placed on the shelf layer and has a cylindrical shape. A lid having a circular structure is provided at the top of the seed crystal box. Small arch-shaped holes are uniformly distributed in the sidewall of the seed crystal box. Large circular holes are formed in the bottom of the seed crystal box. The bottom of the seed crystal box is connected to a skirt band. The silicon carbide single-crystal growth device without bonding seed crystals can be applied to crystal growth of 4 inches, 6 inches or even larger sizes, greatly reduces the planar hexagonal defects in the crystals, and obtains high-quality silicon carbide single crystals. The silicon carbide single-crystal growth device can reduce the risk of physical injury and crystal damage caused by improper operation during crystal removal.

Description

Silicon carbide single crystal growth device without bonding seed crystal

Cross-reference of related applications

This application requires the priority of the Chinese patent application filed on October 31, 2018, with the application number CN201811282839.3 and the name "a silicon carbide single crystal growth device without bonding seed crystals", all of which are The content is incorporated into this application by reference.

Technical field

The present application relates to the technical field of semiconductor manufacturing devices, and in particular to a silicon carbide single crystal growth device that does not require seed crystal bonding.

Background technique

Because of its wide band gap, high thermal conductivity, high breakdown electric field, and high radiation resistance, the silicon carbide single crystal material can produce semiconductor devices that can meet today's demand for high power and strong radiation devices. Ideal substrate material for high-temperature, high-frequency, high-power and radiation-resistant devices, and it has emerged in the fields of hybrid vehicles, high-voltage power transmission, LED lighting and aerospace, and the growth of high-quality SiC crystals is the realization of these SiC-based devices The basis of excellent performance.

SiC crystals do not appear in nature, and can only be obtained by synthetic methods. At present, the methods of silicon carbide single crystal mainly include physical vapor transmission method, high temperature chemical vapor deposition method and liquid phase epitaxy method. Among them, the physical vapor transmission method is the most mature, and this method is adopted by most research institutions and companies in the world. The physical vapor deposition method (PVT) is very difficult. The silicon carbide powder must be directly sublimated into Si, Si ₂ C, SiC ₂ and other gases at a temperature above 2100 ° C and a low pressure environment, and then transferred from the high temperature region to the temperature gradient The seed crystals in the lower temperature region are deposited and crystallized into silicon carbide single crystals.

The physical vapor deposition method (PVT) grows silicon carbide single crystal seed crystals in most of the fixation method using glue to paste the seed crystal method, however, in the process of mechanical bonding, often leave scratches on the back of the seed crystal. Moreover, during the pasting process, voids may be generated between the back of the seed crystal and the crucible cover due to air bubbles, resulting in the generation of defects in the crystal, which will have a great impact on the quality of the crystal. Moreover, the difference between the thermal expansion coefficients of the seed crystal and the crucible cover can also cause internal stress in the seed crystal. How to stick the seed crystal to the crucible cover well, and then place the entire seed crystal holder in the crucible can be suitable for crystal growth, has become a crucial step. However, the materials and seed crystals used in the entire reaction unit are different. This mechanical and rigid paste method can easily introduce internal gravity during the crystal growth process. For example, the current physical vapor deposition method (PVT) uses an adhesive to bond the seed crystal to the crucible lid. This method is likely to cause the seed crystal to bend and deform during the bonding process, which leads to the introduction of undesirable crystals. Internal stress, and the internal stress generated during the growth of SiC crystals can easily cause the crystal to crack during subsequent processing, seriously affecting the yield of the crystal.

At present, the physical vapor deposition (PVT) seed crystal is glued on the crucible lid for growth, but there are four problems:

1. The chip drop rate is high, the general glue cannot withstand such a high temperature, resulting in a very high chip drop rate;

2. The cost is high, the glue that can withstand this temperature is expensive, and the high temperature treatment of 1800-2300 ℃ under high vacuum or inert atmosphere is required after the glue is glued, which is costly and time-consuming, requires a high-temperature furnace or requires a large amount of inert gas and 1-4 days Cycle processing cycle, which makes the method costly;

3. Due to the temperature gradient between the seed crystal and the seed crystal holder, thermal evaporation will occur on the backside of the seed crystal. Thermal evaporation and crystal growth on the backside of the seed crystal are a reverse process. The backside evaporation is preferentially generated in areas with higher temperatures or areas with dense defects ; The temperature of the pore area on the backside of the seed crystal is higher than that of the carbonized binder area, so the backside evaporation is likely to occur in the pore area. The vapor phase generated by evaporation first accumulates in the pore area. During the crystal growth process, although the graphite crucible used is High graphite, but its porosity is still as high as more than 10%. The voids in the graphite cover will cause the gas phase material accumulated in the pore area on the back of the seed crystal to escape. The gas phase material escape is a continuous process. Evaporate, the gaseous substance generated by evaporation continuously escapes from the pores of the graphite cover, resulting in planar hexagonal defects in the grown crystal. This defect is a fatal defect, and its formation will drastically reduce the quality and yield of the wafer;

4. Existing technology, when the crystal growth is completed, the mechanical cutting crucible cover needs to be used to remove the crystal, and the device only needs to take out the box after opening the crucible to easily remove the crystal, which can reduce the personnel caused by cutting Risk, such as the risk of personnel injury or crystal damage due to improper operation.

Chinese patent CN107829134A discloses an aluminum nitride single crystal growth device and method without seed crystal bonding technology, the growth device includes: heating system, infrared temperature measurement system, seed crystal, growth crucible, crucible separator and double nesting Crucible; the heating system is placed on the outermost side; there is a temperature difference between the bottom and the top of the crucible; the crucible is placed in the insulation material; the seed crystal is placed on the bottom of the crucible; the double nested crucible is placed vertically on the upper side of the crucible separator, Including the inner crucible and the outer crucible; the height of the inner and outer crucible walls remains the same; high purity aluminum nitride powder is filled between the inner and outer crucible side walls. But the device of this patent is complicated and not easy to control.

Summary of the invention

In view of the above problems, the present application provides a silicon carbide single crystal growth device that does not require seed crystal bonding.

The technical solution adopted by the present application to solve the above problems is: a silicon carbide single crystal growth device that does not require seed crystal bonding, including a seed crystal box 1 and a crucible 2; a shelf layer 8 is provided inside the crucible 2; the shelf layer 8 is used for Place the seed crystal box 1; the seed crystal box 1 adopts a cylindrical shape; the top of the seed crystal box 1 is provided with a ring-shaped structure cover 4; the side wall of the seed crystal box 1 is provided with arch-shaped holes 5 arranged uniformly; the seed crystal The bottom of the box 1 is provided with a large round hole 9; the bottom of the seed box 1 is connected with a skirt belt 6. Among them, the semi-circular small holes provided on the bottom skirt of the seed box and the arch-shaped small holes on the side wall are used to guide the gas when the crystal grows, and the gas flows from the bottom into the semi-circle on the skirt Small holes, then flow into the arch-shaped small holes, and finally flow out from the top; the bottom of the seed box plays the role of placing the seed crystal, and ensures that the seed crystal can still be in the ideal position while bending and expanding under heat; the top of the graphite box In order to maintain the vertical position of the seed crystal and prevent the seed crystal from directly contacting with the crucible cover; .

Further, the inner diameter of the upper part of the crucible 2 is 150 mm to 170 mm, and the inner diameter of the lower part is 130 mm to 150 mm.

Further, the material of the seed box 1 is selected from one of metal molybdenum and graphite.

Furthermore, the material of the seed crystal box 1 is graphite.

Furthermore, the surface of the seed crystal box 1 is plated with any one of tantalum carbide, niobium carbide, or tungsten carbide. Among them, any one of tantalum carbide, niobium carbide or tungsten carbide plated on the surface of the seed box can prolong the service life of the graphite box.

Further, the size of the seed crystal box 1 is: a diameter of 140 mm to 160 mm, a height of 15 mm to 25 mm, and a wall thickness of 3 mm to 8 mm.

Further, the small holes 5 are arranged in two layers on the side wall of the seed crystal box.

Further, the seed crystal 3 is placed on the large circular hole 9.

Further, the skirt 6 has a hollow structure.

Further, the skirt 6 is provided with a semi-circular small hole with the same height as the skirt.

The advantages of this application are:

(1) The silicon carbide single crystal growth device of this application does not require the bonding of seed crystals. The silicon carbide seed crystals are placed through the seed crystal box, and the use of glue paste is eliminated, which overcomes many problems caused by the use of glue paste, and the growth is completed After removing the crystal, the box can be reused multiple times after removing the polycrystal by high-temperature calcination at a later stage;

(2) The silicon carbide single crystal growth device without bonding seed crystals of this application can be applied to crystal growth of 4 inches and 6 inches, or even larger sizes; the planar hexagonal defects in the crystals are greatly reduced, and high quality is obtained Silicon carbide single crystal; it can reduce the risk of personal injury and crystal damage due to improper handling during crystal handling.

In addition to the objectives, features, and advantages described above, the present application has other objectives, features, and advantages. The application will be described in further detail below with reference to the drawings.

BRIEF DESCRIPTION

In order to more clearly explain the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, without paying any creative work, other drawings can be obtained based on these drawings. In the drawings:

FIG. 1 is a plan view of a silicon carbide single crystal growth device without the need for bonding seed crystals.

Fig. 2 is a cross-sectional view of the A-A surface of a silicon carbide single crystal growth device that does not require seed crystal bonding.

Fig. 3 is a front view of a seed crystal box.

The marks in the picture are: 1. Seed crystal box; 2. Crucible; 3. Seed crystal; 4. Cover; 5. Small hole; 6. Skirt; 7. Silicon carbide material; 8. Shelf layer; 9. Large round hole.

detailed description

The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in this application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of this application.

Example 1

A silicon carbide single crystal growth device without seed crystal bonding, including a seed crystal box and a crucible; the inner diameter of the upper part of the crucible is 150mm and the inner diameter of the lower part is 130mm; a shelf layer is arranged inside the crucible, and the shelf layer is used for placing the seed crystal box; The seed crystal box adopts a cylindrical shape. The material of the seed crystal box is selected from metal molybdenum. The size of the seed crystal box is: diameter 140mm, height 15mm, wall thickness 3mm; the top of the seed crystal box is provided with a ring structure cover, and the inner diameter of the cover is 100mm, the outer diameter is 130mm; the side wall of the seed crystal box is provided with evenly arranged arch-shaped small holes. The small holes are arranged in two layers on the side wall of the seed crystal box, and the size of the small holes is set to be 1mm wide. The height is 2mm, and the hole spacing is 1mm; the bottom of the seed box is provided with a large circular hole with a diameter of 100mm, and the seed crystal is placed on the large round hole; the bottom of the seed box is connected with a skirt, the skirt is hollow, the height of the skirt is 3mm, and the thickness is 3mm, the skirt has a semi-circular small hole with a height of 3mm.

Example 2

A silicon carbide single crystal growth device that does not require seed crystal bonding, including a seed crystal box and a crucible; the inner diameter of the upper part of the crucible is 170 mm and the inner diameter of the lower part is 150 mm; a shelf layer is provided inside the crucible for placing the seed crystal box; The seed crystal box adopts a cylindrical shape, the material of the seed crystal box is graphite, the surface of the seed crystal box is coated with tantalum carbide, the size of the seed crystal box is: diameter 160mm, height 25mm, wall thickness 5mm; the top of the seed crystal box is provided with a ring The structure of the cover, the inner diameter of the cover is 110mm, the outer diameter is 150mm; the side wall of the seed crystal box is provided with uniformly arranged arch-shaped small holes, the small holes are arranged in two layers on the side wall of the seed crystal box, the small holes The size setting is: width 2mm, height 3mm, small hole interval is 4mm; the bottom of the seed crystal box is provided with a large circular hole with a diameter of 120mm, the seed crystal is placed on the large round hole; the bottom of the seed crystal box is connected with a skirt, the skirt is hollow structure, The height of the skirt is 7mm, the thickness is 5mm, and the skirt is provided with a semi-circular small hole with a height of 7mm.

Example 3

A silicon carbide single crystal growth device that does not require seed crystals includes a seed crystal box and a crucible; the inner diameter of the upper part of the crucible is 160mm and the inner diameter of the lower part is 140mm; a shelf layer is provided inside the crucible for placing the seed crystal box; The seed crystal box adopts a cylindrical shape, the material of the seed crystal box is graphite; the surface of the seed crystal box is coated with niobium carbide, the size of the seed crystal box is: diameter 150mm, height 18mm, wall thickness 6mm; the top of the seed crystal box is provided with A ring-shaped lid with an inner diameter of 120mm and an outer diameter of 130mm; the side wall of the seed crystal box is provided with uniformly arranged arch-shaped small holes, and the small holes are arranged in two layers on the side wall of the seed crystal box. The size of the hole is set as follows: width 4mm, height 5mm, small hole interval is 2mm; the bottom of the seed crystal box is provided with a large round hole with a diameter of 110mm, and the seed crystal is placed on the large round hole; the bottom of the seed crystal box is connected with a skirt, the skirt is hollow structure The height of the skirt is 5mm, the thickness is 6mm, and the skirt is provided with a semi-circular small hole with a height of 5mm.

Example 4

A silicon carbide single crystal growth device that does not require seed crystals includes a seed crystal box and a crucible; the inner diameter of the upper part of the crucible is 150mm and the inner diameter of the lower part is 140mm; a shelf layer is provided inside the crucible for placing the seed crystal box; The seed crystal box adopts a cylindrical shape, the material of the seed crystal box is graphite; the surface of the seed crystal box is coated with tungsten carbide, the size of the seed crystal box is: diameter 145mm, height 20mm, wall thickness 8mm; the top of the seed crystal box is provided with a ring The structure of the cover, the inner diameter of the cover is 100mm, the outer diameter is 140mm; the side wall of the seed box is provided with uniformly arranged arch-shaped holes, the holes are arranged in two layers on the side wall of the seed box, the small holes The size setting is: width 3mm, height 4mm, small hole spacing is 3mm; the bottom of the seed crystal box is provided with a large circular hole with a diameter of 100mm, and the seed crystal is placed on the large round hole; the bottom of the seed crystal box is connected with a skirt, the skirt is hollow structure, The height of the skirt is 4mm, the thickness is 8mm, and the skirt is provided with a semi-circular small hole with a height of 4mm.

Example 5

A silicon carbide single crystal growth device without seed crystal bonding, including a seed crystal box and a crucible; the inner diameter of the upper part of the crucible is 170mm, and the inner diameter of the lower part is 130mm; a shelf layer is provided inside the crucible, and the shelf layer is used for placing the seed crystal box; The seed crystal box adopts a cylindrical shape, the material of the seed crystal box is graphite; the surface of the seed crystal box is plated with tantalum carbide, the size of the seed crystal box is: diameter 140mm, height 22mm, wall thickness 4mm; the top of the seed crystal box is provided with a ring The structure of the cover, the inner diameter of the cover is 115mm, the outer diameter is 135mm; the side wall of the seed crystal box is provided with uniformly arranged arch-shaped small holes, the small holes are arranged in two layers on the side wall of the seed crystal box, the small holes The size setting is: width 2mm, height 3mm, small hole spacing 2mm; the bottom of the seed crystal box is provided with a large circular hole with a diameter of 120mm, and the seed crystal is placed on the large round hole; the bottom of the seed crystal box is connected with a skirt, the skirt is hollow structure, The height of the skirt is 4mm, the thickness is 5mm, and the skirt is provided with a semi-circular small hole with a height of 4mm.

The above are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement and improvement made within the spirit and principle of this application shall be included in the protection scope of this application.

Claims

A silicon carbide single crystal growth device without bonding seed crystals, characterized in that the silicon carbide single crystal growth device without bonding seed crystals includes a seed crystal box (1) and a crucible (2); the crucible ( 2) A shelf layer (8) is provided inside; the shelf layer (8) is used for placing a seed crystal box (1); the seed crystal box (1) adopts a cylindrical shape; the top of the seed crystal box (1) A cover (4) with a ring structure is provided; the side walls of the seed crystal box (1) are provided with uniformly arranged arch-shaped small holes (5); the bottom of the seed crystal box (1) is provided with large round holes ( 9); a skirt (6) is connected to the bottom of the seed box (1).
The silicon carbide single crystal growth device according to claim 1, wherein the inner diameter of the upper part of the crucible (2) is 150 mm to 170 mm, and the inner diameter of the lower part is 130 mm to 150 mm.
The silicon carbide single crystal growth device without bonding seed crystals according to claim 1, characterized in that the material of the seed crystal box (1) is selected from one of metal molybdenum and graphite.
The silicon carbide single crystal growth device without bonding seed crystals according to claim 3, characterized in that the material of the seed crystal box (1) is graphite.
The silicon carbide single crystal growth device without bonding seed crystals according to claim 4, characterized in that the surface of the seed crystal box (1) is plated with any one of tantalum carbide, niobium carbide or tungsten carbide.
The silicon carbide single crystal growth device without bonding seed crystals according to claim 1, characterized in that the size of the seed crystal box (1) is: diameter 140mm ~ 160mm, height 15mm ~ 25mm, wall thickness 3mm ~ 8mm.
The silicon carbide single crystal growth device without bonding seed crystals according to claim 1, characterized in that the small holes (5) are arranged in two layers on the side wall of the seed crystal box.
The silicon carbide single crystal growth device without bonding seed crystals according to claim 1, characterized in that a seed crystal (3) is placed on the large circular hole (9).
The silicon carbide single crystal growth device without bonding seed crystals according to claim 1, characterized in that the skirt (6) has a hollow structure.
The silicon carbide single crystal growth device without bonding seed crystals according to claim 1, characterized in that the skirt (6) is provided with semi-circular small holes having the same height as the skirt.