CN114959900A - Silicon carbide single crystal growth device with radial temperature adjusting ring - Google Patents

Abstract

The invention discloses a silicon carbide single crystal growth device with a radial temperature adjusting ring, which relates to the technical field of silicon carbide single crystal preparation and crystal growth. The silicon carbide single crystal growth device with radial temperature adjustment ring includes a sealed cavity, a heat preservation structure, a heating structure, a crucible and a temperature uniformity ring, etc. The crucible is used for placing source materials, and the seed crystal is installed on the top of the crucible. Multiple sets of heating mechanisms and thermal insulation structures are used to adjust the radial temperature gradient at the seed crystal. The silicon carbide single crystal growth device with a radial temperature adjustment ring can dynamically adjust the radial temperature gradient at the seed crystal in real time, and the adjustment method is simple, the effect speed is fast, and the unevenness of the growth surface of the silicon carbide single crystal ingot can be effectively controlled. It is beneficial to the growth of large-sized silicon carbide single crystal ingots.

Description

A silicon carbide single crystal growth device with radial temperature adjustment ring

technical field

The invention relates to the technical field of preparation and crystal growth of silicon carbide single crystal, in particular to a silicon carbide single crystal growth device with a radial temperature adjustment ring.

Background technique

Silicon carbide is a high-quality wide-bandgap semiconductor material with the advantages of wide band gap, high breakdown electric field, high thermal conductivity, and high saturation electron drift rate, which can meet the needs of high-temperature, high-power, low-loss and large-diameter devices. Silicon carbide single crystals cannot be formed by the melting method. The sublimation growth technology based on the improved Lely method, the physical vapor transport method (PVT method), is a common method for obtaining silicon carbide single crystals. The growth principle of silicon carbide single crystal prepared by PVT method is: high-purity silicon carbide powder source is decomposed at high temperature to form gaseous substances (mainly Si, SiC ₂ , Si ₂ C, etc.), and these gaseous substances are driven by supersaturation. Sublimation to the seed crystal at the cold end for growth. Supersaturation is caused by the temperature gradient between the seed crystal and the powder source.

In the current commonly used induction heating method, during the crystal growth process, the temperature is controlled by adjusting the power of the induction coil and the axial relative position of the induction coil and the crucible, so that the source of silicon carbide powder in the crucible and the seed crystal produce appropriate temperature. The temperature gradient enables the crystal to grow continuously. The flexibility of temperature adjustment of the induction heating method is very limited. When the induction coil moves axially, the axial temperature can be adjusted on the one hand, but the radial temperature gradient will also change accordingly. The seed radial temperature gradient cannot be controlled independently. However, the resistance heating crystal growth furnaces currently on the market have a low degree of coupling between the radial temperature and the axial temperature, but the radial temperature cannot be adjusted in the dynamic region.

In view of this, it is particularly important to develop and design a silicon carbide single crystal growth device that can solve the above technical problems and can adjust the temperature gradient radially.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides a silicon carbide single crystal growth device with a radial temperature adjustment ring, which can dynamically adjust the radial temperature of the seed crystal in real time, with simple adjustment and rapid dynamic response, thereby reducing the size of the silicon carbide single crystal. The radial temperature gradient of the crystal during the growth process can effectively reduce the defects of crystal growth and ensure the quality of the crystal.

For achieving the above object, the present invention provides the following scheme:

The invention provides a silicon carbide single crystal growth device with a radial temperature adjustment ring, which includes a sealing cavity, a heating structure, a heat preservation structure and a temperature measurement mechanism; the heat preservation structure is arranged in the sealing cavity; the heating structure is provided with In the thermal insulation structure, the temperature measuring mechanism is arranged on the sealed cavity; the crucible is arranged in the thermal insulation structure, and the seed crystal is arranged in the crucible; there is a uniform space between the heating structure and the crucible. temperature ring.

Optionally, the sealed cavity includes a cavity, an upper flange of the cavity and a lower flange of the cavity, the upper flange of the cavity can be opened on the top of the cavity, and the lower flange of the cavity is set at the bottom of the cavity; the cavity is provided with a cavity air outlet.

Optionally, the heating structure includes an upper auxiliary heating resistance, a lower main heating resistance and a radial temperature adjustment resistance; the upper auxiliary heating resistance, the lower main heating resistance and the radial temperature adjustment resistance operate independently; The upper auxiliary heating resistor is arranged in the upper part of the thermal insulation structure; the lower main heating resistor is arranged in the middle and lower part of the thermal insulation structure; the upper end face of the radial temperature regulating resistor is flush with the upper surface of the seed crystal The upper auxiliary heating resistor, the lower main heating resistor and the radial temperature adjusting resistor are respectively provided with a set of lead-out electrodes.

Optionally, the thermal insulation structure includes an external thermal insulation structure and an internal thermal insulation structure, the external thermal insulation structure includes an external thermal insulation structure upper cover, an external thermal insulation structure cylinder and an external thermal insulation structure lower cover, and the internal thermal insulation structure is divided into a first internal thermal insulation structure, The second internal thermal insulation structure, the third internal thermal insulation structure and the fourth internal thermal insulation structure; the upper cover of the external thermal insulation structure is arranged on the top of the cylinder of the external thermal insulation structure, and the lower cover of the external thermal insulation structure is arranged on the external thermal insulation structure At the bottom of the cylinder, the first internal thermal insulation structure and the second internal thermal insulation structure are arranged on the upper part of the crucible, the third internal thermal insulation structure is arranged on the side of the crucible, and the fourth internal thermal insulation structure is arranged on the crucible lower part.

Optionally, the temperature measurement mechanism includes an upper temperature measurement device, a lower temperature measurement device, and a side temperature measurement device, and the upper temperature measurement device, the lower temperature measurement device, and the side temperature measurement device are respectively arranged on the Seal the top, bottom and sides of the cavity.

Optionally, the upper temperature measurement device, the side temperature measurement device and the lower temperature measurement device are all infrared thermometers or thermocouples.

Optionally, an inflation port is provided on the sealing cavity.

Optionally, the temperature uniformity ring is made of graphite material or carbon-carbon composite material or high temperature ceramic or titanium diboride or titanium carbide material.

The present invention has achieved the following technical effects with respect to the prior art:

The silicon carbide single crystal growth device with radial temperature adjustment ring in the present invention mainly includes a sealed cavity, a heating structure, a heat preservation structure and a temperature measuring mechanism; the heating structure can realize the heating of the bottom, surrounding and top of the crucible, and The auxiliary heating resistor can control the temperature at the top of the crucible, the lower main heating resistor can control the temperature at the bottom of the crucible, and the radial temperature adjusting resistor can control the radial temperature of the seed crystal. A layer of graphite material or carbon-carbon composite material is arranged between the heating structure and the crucible. Or high temperature ceramic or titanium diboride or titanium carbide material made of temperature uniformity ring, can effectively ensure the uniformity of temperature change, combined with the temperature measurement mechanism to measure the temperature of the crucible top, crucible top side and crucible bottom respectively, to achieve the seed crystal The radial temperature can be dynamically adjusted in real time, thereby reducing the radial temperature gradient and stress of the crystal during the growth of silicon carbide single crystal, which can effectively reduce the defects of crystal growth and ensure the quality of the crystal.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a silicon carbide single crystal growth device with a radial temperature adjustment ring according to the present invention.

FIG. 2 is a schematic diagram of the thermal insulation structure of the silicon carbide single crystal growth device with a radial temperature adjustment ring according to the present invention.

FIG. 3 is a schematic view of the heating structure of the silicon carbide single crystal growth device with radial temperature adjustment ring according to the present invention.

Explanation of reference numerals: 1. Upper temperature measuring device; 2. Upper air inlet; 3. Upper flange of cavity; 4. Air suction port of cavity; 5. Cavity; 6. Lower flange of cavity; 7. Lower inflation 8. Lower temperature measuring equipment; 9. Lead-out electrode; 10. Thermal insulation structure; 101. Upper cover of external thermal insulation structure; 102. External thermal insulation structure cylinder; 103. Lower cover of external thermal insulation structure; 104. First internal thermal insulation structure 105, the second internal thermal insulation structure; 106, the third internal thermal insulation structure; 107, the fourth internal thermal insulation structure; 11, the heating structure; 111, the upper auxiliary heating resistance; Resistance; 12, crucible; 13, temperature uniformity ring; 14, side temperature measurement equipment; 15, seed crystal.

Detailed ways

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

Example 1:

As shown in FIG. 1 , this embodiment provides a silicon carbide single crystal growth device with a radial temperature adjustment ring, which includes a sealed cavity, a heating structure, a thermal insulation structure, and a temperature measurement mechanism; the thermal insulation structure is arranged in the sealed cavity the heating structure is arranged in the heat preservation structure, the temperature measurement mechanism is arranged on the sealed cavity; the crucible 12 is arranged in the heat preservation structure, and the seed crystal 15 is arranged in the crucible 12; the There is a temperature equalizing ring 13 between the heating structure and the crucible 12 .

In this specific embodiment, the sealed cavity includes a cavity 5, an upper flange 3 of the cavity and a lower flange 6 of the cavity, and the upper flange 3 of the cavity is openably arranged on the top of the cavity 5, The lower flange 6 of the cavity is arranged at the bottom of the cavity 5 ; the cavity 5 is provided with a cavity air outlet 4 . The upper flange 3 of the cavity and the lower flange 6 of the cavity can be connected with the cavity 5 by bolts, and the lower flange 6 of the cavity can also be welded to the cavity 5, which can ensure the upper flange 3 of the cavity and the lower flange of the cavity 5. The connection strength between the flange 6 and the cavity 5 is sufficient to ensure the sealing performance of the connection. The cavity suction port 4 is used to evacuate the inside of the sealed cavity, so that the crystal growth can reach the necessary pressure environment.

The heating structure 11 includes an upper auxiliary heating resistor 111, a lower main heating resistor 113 and a radial temperature adjusting resistor 112; the upper auxiliary heating resistor 111, the lower main heating resistor 113 and the radial temperature adjusting resistor 112 are independent Operation; the upper auxiliary heating resistor 111 is arranged in the upper part of the insulation structure; the lower main heating resistance 113 is arranged in the middle and lower part of the insulation structure; The surfaces are flush (the relative position of the radial temperature adjustment resistor 112 and the seed crystal 15 is adjusted according to the process requirements); by adjusting the power of the radial temperature adjustment resistor 112, the temperature gradient in the radial direction of the seed crystal can be individually controlled; three groups The resistors respectively have a set of lead-out electrodes, which are the upper lead-out electrodes, the lower lead-out electrodes and the middle lead-out electrodes corresponding to the upper auxiliary heating resistance 111, the lower main heating resistance 113 and the radial temperature adjusting resistance 112; the arrangement of the middle lead-out electrodes is given priority. Pass through the lower flange of the cavity, and seal the connection with the lower flange by the combination of flange and O-ring. Since the temperature of the part of the radial temperature regulating resistor 112 located in the sealed cavity exceeds 2000 degrees Celsius, the part of the middle lead-out electrode outside the sealed cavity is close to the indoor temperature (about 20 degrees Celsius), and the temperature difference between the two is relatively large. Therefore, the longer middle lead out The electrode can make the temperature change of the middle-extracted electrode have a relatively slow transition process and reduce energy consumption. It is also possible to choose the arrangement of the middle-extracted electrodes as radial lead-out, passing through the cavity, and leading out from the side of the cavity.

The thermal insulation structure 10 includes an external thermal insulation structure and an internal thermal insulation structure. The external thermal insulation structure includes an external thermal insulation structure upper cover 101, an external thermal insulation structure cylinder 102 and an external thermal insulation structure lower cover 103. The internal thermal insulation structure is divided into a first internal thermal insulation structure 104. , the second internal thermal insulation structure 105, the third internal thermal insulation structure 106 and the fourth internal thermal insulation structure 107; the external thermal insulation structure upper cover 101 is arranged on the top of the external thermal insulation structure cylinder 102, and the external thermal insulation structure lower cover 103 The first internal thermal insulation structure 104 and the second internal thermal insulation structure 105 are arranged on the upper part of the crucible 12 , and the third internal thermal insulation structure 106 is arranged on the side of the crucible 12 . , the fourth internal heat preservation structure 107 is arranged at the lower part of the crucible 12 .

The heat preservation structure 10 provides an appropriate temperature environment for the entire crucible 12, thereby reducing heat dissipation in the entire growth environment.

The temperature measurement mechanism includes an upper temperature measurement device 1, a side temperature measurement device 14 and a lower temperature measurement device 8. The upper temperature measurement device 1 and the lower temperature measurement device 8 are respectively arranged on the top and bottom of the sealed cavity, The side temperature measuring device 14 is located in the direction of the top plane of the crucible 12 . Specifically, a temperature measurement pipeline is respectively provided in the middle of the upper flange 3 of the cavity and the lower flange 6 of the cavity, and the upper temperature measurement device 1 and the lower temperature measurement device 8 are respectively arranged on the upper flange 3 of the cavity and the lower part of the cavity. On the temperature measuring pipe on the flange 6, the side temperature measuring device 14 is used to measure the temperature of the top side of the crucible 12.

An upper air inlet 2 is provided on one side of the temperature measurement pipeline on the upper flange 3 of the cavity, and a lower air inlet 7 is arranged on one side of the temperature measurement pipeline on the lower flange 6 of the cavity. The upper gas inlet 2 and the lower gas inlet 7 are used to input process gas; more, the process gas can be used as a purge gas to purge the temperature measurement pipeline to avoid contamination of impurities on the temperature measurement pipeline or temperature measurement glass, which will affect the accuracy of temperature measurement sex.

The temperature uniformity ring 13 is located between the heating structure and the crucible, and the material is graphite material or carbon-carbon composite material or high temperature ceramics or titanium diboride or titanium carbide material. The thickness needs to ensure the strength of the entire temperature uniformity ring, and the thickness can be 5 ~10mm. Since the heating structure is generally grid-shaped or column-shaped, there are gaps between the grids or columns, and the heating of the crucible is uneven, which will lead to local sudden changes in temperature, and the temperature change gradient is not uniform enough, which is not conducive to the growth of high-quality crystals. A layer of temperature uniformity ring 13 is conducive to a more uniform change of the axial temperature.

The upper temperature measuring device 1 , the side temperature measuring device 14 and the lower temperature measuring device 8 are all infrared thermometers or thermocouples.

It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. . Therefore, the embodiments are to be regarded in all respects as illustrative and not restrictive, and the scope of the invention is to be defined by the appended claims rather than the foregoing description, which are therefore intended to fall within the scope of the claims. All changes that come within the meaning and range of equivalents of , are intended to be embraced within the invention, and any reference signs in the claims shall not be construed as limiting the involved claim.

In this specification, specific examples are used to illustrate the principles and implementations of the present invention, and the descriptions of the above embodiments are only used to help understand the method and the core idea of the present invention; There will be changes in the specific implementation manner and application scope of the idea of the invention. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (8)

1. A silicon carbide single crystal growth device with a radial temperature adjustment ring, characterized in that it comprises a sealed cavity, a heating structure, a thermal insulation structure and a temperature measurement mechanism; the thermal insulation structure is arranged in the sealed cavity; the The heating structure is set in the heat preservation structure, the temperature measuring mechanism is set on the sealed cavity; the crucible is set in the heat preservation structure, and the seed crystal is set in the crucible; the heating structure is connected with the crucible. There is a uniform temperature ring. 2 . The silicon carbide single crystal growth device with a radial temperature adjustment ring according to claim 1 , wherein the sealed cavity comprises a cavity, an upper flange of the cavity and a lower flange of the cavity, and the cavity The upper flange of the body is openably arranged on the top of the cavity, the lower flange of the cavity is arranged at the bottom of the cavity; the cavity is provided with a cavity air outlet. 3. The silicon carbide single crystal growth device with a radial temperature adjustment ring according to claim 1, wherein the heating structure comprises an upper auxiliary heating resistor, a lower main heating resistor and a radial temperature adjustment resistor; the The upper auxiliary heating resistance, the lower main heating resistance and the radial temperature regulating resistance operate independently; the upper auxiliary heating resistance is arranged in the upper part of the heat preservation structure; the lower main heating resistance is arranged in the heat preservation structure The middle and lower part; the upper end face of the radial temperature adjustment resistor is flush with the upper surface of the seed crystal, and the upper auxiliary heating resistor, the lower main heating resistor and the radial temperature adjustment resistor are respectively arranged in one group Extract the electrode. 4 . The silicon carbide single crystal growth device with radial temperature adjusting ring according to claim 1 , wherein the thermal insulation structure comprises an external thermal insulation structure and an internal thermal insulation structure, and the external thermal insulation structure comprises an external thermal insulation structure upper cover, The external thermal insulation structure cylinder body and the external thermal insulation structure lower cover, the internal thermal insulation structure is divided into a first internal thermal insulation structure, a second internal thermal insulation structure, a third internal thermal insulation structure and a fourth internal thermal insulation structure; the external thermal insulation structure upper cover is arranged on The top of the external thermal insulation structure cylinder, the lower cover of the external thermal insulation structure is arranged on the bottom of the external thermal insulation structure cylinder, the first internal thermal insulation structure and the second internal thermal insulation structure are arranged on the upper part of the crucible, and the first internal thermal insulation structure is arranged on the top of the crucible. Three internal thermal insulation structures are arranged on the side of the crucible, and the fourth internal thermal insulation structure is arranged on the lower part of the crucible. 5 . The silicon carbide single crystal growth device with a radial temperature adjustment ring according to claim 1 , wherein the temperature measurement mechanism comprises an upper temperature measurement device, a lower temperature measurement device and a side temperature measurement device, and the The upper temperature measuring device, the lower temperature measuring device and the side temperature measuring device are respectively arranged on the top, bottom and side of the sealed cavity. 6 . The silicon carbide single crystal growth device with radial temperature adjustment ring according to claim 5 , wherein the upper temperature measurement device, the side temperature measurement device and the lower temperature measurement device are all infrared Thermometer or thermocouple. 7 . The silicon carbide single crystal growth device with a radial temperature adjusting ring according to claim 1 , wherein the sealing cavity is provided with an air inlet. 8 . 8 . The silicon carbide single crystal growth device with radial temperature adjusting ring according to claim 1 , wherein the temperature adjusting ring is made of graphite material or carbon-carbon composite material or high temperature ceramics or titanium diboride or carbonized carbide. 9 . Made of titanium material.

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