Single crystal furnace device

Abstract

The utility model relates to the technical field of semiconductor materials, and discloses a single crystal furnace device which comprises a furnace body, a quartz cover and a heater, the upper end of the furnace body is provided with a lead screw elevator, the bottom end in the furnace body is provided with a base in a sliding manner, the quartz cover is supported on the base, and a closed space is formed between the quartz cover and the base; an outer crucible is arranged in the closed space, an inner crucible and a crucible support are sealed in the outer crucible, the crucible support comprises a first heat conduction part and a second heat conduction part which are different in heat conductivity coefficient, the first heat conduction part supports a shoulder placing part of the inner crucible, and the second heat conduction part supports the first heat conduction part; the heater is arranged on the outer side of the quartz cover in a sleeving mode and connected with a lead screw of the lead screw elevator. According to the single crystal furnace device provided by the utility model, crystal defects caused by mechanical disturbance are avoided, the temperature gradient of a growth interface is reduced, and the crystal growth interface is a convex interface, so that low-dislocation crystals with larger sizes can be conveniently grown.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor materials, in particular to a single crystal furnace device. Background Art

[0002] Gallium arsenide is an important semiconductor material, and its application requires extremely low dislocation density.

[0003] At present, there are three main methods for growing gallium arsenide single crystals: the Czochralski method, the vertical Bridgman crystal method, and the VGF method. However, all three existing methods have certain defects: the temperature gradient of the Czochralski method is large, making it difficult to grow gallium arsenide single crystals with low dislocation density. In the vertical Bridgman method, the mechanical disturbance during crystal growth is large, making it difficult to stably grow large-sized low-dislocation gallium arsenide single crystals. The crystal growth rate of the VGF method is generally slow, and the crystal growth interface is mostly a concave interface, making it difficult to grow large-sized low-dislocation crystals. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a single crystal furnace device to avoid gallium arsenide crystal defects caused by mechanical disturbances, reduce the temperature gradient of the growth interface, and the crystal growth interface is a convex interface, which is convenient for growing larger low-dislocation crystals.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] A single crystal furnace device comprises a furnace body, a quartz cover and a heater, wherein a screw lift is provided at the upper end of the furnace body, a base is slidably provided at the bottom end of the furnace body, the quartz cover is supported on the base and forms a closed space with the base;

[0007] An outer crucible is arranged in the enclosed space, an inner crucible and a crucible support are sealed in the outer crucible, the crucible support comprises a first heat conducting portion and a second heat conducting portion with different thermal conductivities, the first heat conducting portion supports a shoulder portion of the inner crucible, and the second heat conducting portion supports the first heat conducting portion;

[0008] The heater is sleeved on the outer side of the quartz cover and connected to the lead screw of the lead screw lifting machine.

[0009] Preferably, the thermal conductivity of the first heat conducting part is smaller than the thermal conductivity of the second heat conducting part.

[0010] Preferably, the thermal conductivity of the first heat-conducting part is 0.05-25 W / mk, and the thermal conductivity of the second heat-conducting part is 0.5-30 W / mk.

[0011] Preferably, the heater is composed of a plurality of sections of heater units, and the plurality of sections of heater units are distributed along the length direction of the heater, and each section of the heater units can be independently controlled.

[0012] Preferably, there are two screw hoists, and the two screw hoists are respectively connected to two sides of the heater;

[0013] A driving mechanism is provided at the upper end of the furnace body, and the driving mechanism is connected to the two screw hoists.

[0014] Preferably, the driving mechanism comprises a clutch, a first motor and a second motor, one end of the clutch is connected to a first pulley, a first reducer is coaxially connected to the first pulley, and the first reducer is respectively connected to the two screw hoists;

[0015] A second pulley is provided on the output shaft of the first motor, and the second pulley is connected to the first pulley by a belt;

[0016] A second speed reducer and a third speed reducer are connected between the second motor and the other end of the clutch.

[0017] Preferably, a support platform supported on the base is provided in the enclosed space, an end of the second heat conducting part away from the first heat conducting part is inserted into the support platform, and an end surface of one end of the outer crucible connected to the support platform abuts against an upper surface of the support platform.

[0018] Preferably, a mounting groove is provided on the base, a sealing ring is provided on the inner wall of the mounting groove, the quartz cover is inserted into the mounting groove, and a water cooling channel is provided in the base.

[0019] Preferably, a slide rail is provided at the bottom end of the furnace body, and a slider is provided on the base, and the slider is slidably connected in the slide rail.

[0020] Preferably, a roller is provided at the lower end of the furnace body.

[0021] Compared with the prior art, a single crystal furnace device according to an embodiment of the utility model has the following beneficial effects: by connecting the heater to the screw lifter, during the crystal growth process, the crucible, the crystal, and the melt are all stationary, and the heater moves upward, which can maintain stable convection inside the melt and avoid crystal defects caused by mechanical disturbances. By setting the crucible support to a first heat conducting part and a second heat conducting part with different thermal conductivities, the temperature gradient of the growth interface can be adjusted by changing the thermal conductivity of the first heat conducting part and the second heat conducting part of the crucible support, which is conducive to the growth of crystals under different application conditions. It is only necessary to reduce the difference in the thermal conductivity of the first heat conducting part and the second heat conducting part, and the temperature gradient of the growth interface will be reduced. At the same time, it is only necessary to make the thermal conductivity of the first heat conducting part of the crucible support less than the thermal conductivity of the second heat conducting part, so that the growth interface of the crystal can be made a convex interface, which is conducive to impurity removal and facilitates the growth of large-sized low-dislocation crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the single crystal furnace device of the utility model.

[0023] Figure 2 It is a structural schematic diagram of the driving mechanism of the single crystal furnace device of the utility model.

[0024] Figure 3 It is a structural schematic diagram of the base of the single crystal furnace device of the present utility model.

[0025] Wherein: 1-furnace body, 11-slide rail, 2-quartz cover, 3-heater, 4-screw lifter, 5-base, 51-installation slot, 6-outer crucible, 7-inner crucible, 8-crucible support, 81-first heat conducting part, 82-second heat conducting part, 83-sensor, 9-driving mechanism, 91-clutch, 92-first motor, 93-second motor, 94-first pulley, 95-first reducer, 96-second pulley, 97-second reducer, 98-third reducer, a-support platform, b-roller. DETAILED DESCRIPTION

[0026] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0027] like Figure 1 As shown, a single crystal furnace device according to an embodiment of the utility model comprises a furnace body 1, a quartz cover 2 and a heater 3. A screw lifter 4 is provided at the upper end of the furnace body 1, and a roller b is provided at the lower end of the furnace body 1 to facilitate the movement of the furnace body 1. A base 5 is slidably provided at the bottom end of the interior of the furnace body 1, and the quartz cover 2 is supported on the base, and a closed space is formed between the base 5 and the quartz cover 2;

[0028] An outer crucible 6 is provided in the closed space, and an inner crucible 7 and a crucible holder 8 are sealed in the outer crucible 6. The crucible holder 8 includes a first heat conducting portion 81 and a second heat conducting portion 82 with different thermal conductivities. The first heat conducting portion 81 supports the shoulder of the inner crucible 7, and the second heat conducting portion 82 supports the first heat conducting portion 81. The other end of the second heat conducting portion 82 is supported on the base 5.

[0029] The heater 3 is sleeved on the outer side of the quartz cover 2 and connected to the screw of the screw lifting machine 4 .

[0030] Based on the single crystal furnace device with the above characteristics, by connecting the heater 3 to the screw lift 4, during the crystal growth process, the crucible, crystal, and melt are all stationary, and the heater 3 moves upward, which can maintain stable convection inside the melt and avoid crystal defects caused by mechanical disturbance. By setting the crucible holder 8 to a first heat conducting part 81 and a second heat conducting part 82 with different thermal conductivities, the growth interface temperature gradient can be adjusted by changing the thermal conductivity of the first heat conducting part 81 and the second heat conducting part 82 of the crucible holder 8, which is conducive to the growth of crystals under different application conditions. It is only necessary to reduce the difference in thermal conductivity between the first heat conducting part 81 and the second heat conducting part 82, and the growth interface temperature gradient will be reduced. At the same time, it is only necessary to make the thermal conductivity of the first heat conducting part 81 of the crucible holder 8 less than the thermal conductivity of the second heat conducting part 82, so that the growth interface of the crystal can be made into a convex interface, which is conducive to the removal of impurities and facilitates the growth of large-sized low-dislocation crystals.

[0031] In this embodiment, the crucible holder 8 is made of graphite. The thermal conductivity of the first heat conducting part 81 is smaller than that of the second heat conducting part 82, so that the growth interface of the crystal is a convex interface, which is conducive to impurity removal. Specifically, the thermal conductivity of the first heat conducting part 81 is 0.05-25W / mk, and the thermal conductivity of the second heat conducting part 82 is 0.5-30W / mk, which can be selected according to actual conditions. In addition, a sensor 83 is provided in each of the first heat conducting part 81 and the second heat conducting part 82 for monitoring the temperature of the first heat conducting part 81 and the second heat conducting part 82.

[0032] In this embodiment, the heater 3 is composed of a plurality of heater units, and the plurality of heater units are distributed along the length direction of the heater 3. Each heater unit can be independently controlled. By independently controlling each heater unit, a longitudinal temperature gradient can be formed in the inner crucible 7, which is convenient for reducing the temperature gradient and realizing the rapid and good growth of low dislocation density gallium arsenide single crystals.

[0033] Please see attached Figure 2 In this embodiment, there are two screw hoists 4, and the two screw hoists 4 are respectively connected to the two sides of the heater 3. Specifically, a connecting rod is threadedly connected to the screw of each screw hoist 4, and the other ends of the two connecting rods are connected to the heater 3, so that the heater 3 can be driven up and down by the screw hoist 4. Specifically:

[0034] A driving mechanism 9 is provided at the upper end of the furnace body 1, and the driving mechanism 9 is connected to two screw hoists 4 and is used to drive the screw hoists 4. The driving mechanism 9 includes a clutch 91, a first motor 92 and a second motor 93. One end of the clutch 91 is connected to a first pulley 94, and a first reducer 95 is coaxially connected to the first pulley 94. The first reducer 95 is respectively connected to the two screw hoists 4; a second pulley 96 is provided on the output shaft of the first motor 92, and the second pulley 96 is connected to the first pulley 94 by a belt; a second reducer 97 and a third reducer 98 are connected between the second motor 93 and the other end of the clutch 91. The first motor 92 and the second motor 93 are both servo motors, and the speed ratios are different when different motors are working, so that the speed switching and safety braking of the two ends can be realized.

[0035] For example, the speed ratio of the first reducer 95 is 2, the speed ratio of the screw hoist 4 is also 2, the speed ratio of the first motor 92 is 3, the speed ratio of the second motor 93 is 5, the speed ratios of the second reducer 97 and the third reducer 98 are 30 and 20 respectively, then the clutch 91 brake combination can realize the switching of two speeds and safe braking. The first speed ratio is about 120000, and the second speed ratio is 12, which can achieve a lifting speed of 0.001mm~1000mm / min.

[0036] Please refer to the attached Figure 3 In this embodiment, a support platform a supported on the base 5 is provided in the enclosed space, and one end of the second heat conducting part 82 away from the first heat conducting part 81 is inserted into the support platform a to ensure the connection stability between the crucible holder 8 and the support platform a. The end surface of one end of the outer crucible 6 connected to the support platform a is in contact with the upper surface of the support platform a to ensure the sealing between the outer crucible 6 and the support platform a.

[0037] At the same time, in order to ensure the sealing of the enclosed space, a mounting groove 51 is provided on the base 5, and a sealing ring is provided on the inner wall of the mounting groove 51. The quartz cover 2 is inserted into the mounting groove 51, that is, the sealing ring is located between the inner wall of the mounting groove 51 and the outer wall of the quartz cover 2 to ensure the sealing of the enclosed space. Preferably, two sealing rings can be provided. In addition, the base 5 is made of aluminum alloy, and a water cooling channel is provided in the base 5 to ensure the heat dissipation of the base 5.

[0038] In this embodiment, a slide rail 11 is provided at the bottom of the furnace body 1, and a slider is provided on the base 5, and the slider is slidably connected to the slide rail 11, so as to facilitate the replacement of the quartz cover 2 and the crucible support 8. In addition, a buffer limit device and a locking device can also be provided inside the furnace body 1 to ensure the stability of the base 5.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A single crystal furnace device, characterized in that: It comprises a furnace body, a quartz cover and a heater, wherein a screw lift is provided at the upper end of the furnace body, a base is slidably provided at the bottom end of the furnace body, the quartz cover is supported on the base and forms a closed space with the base; An outer crucible is arranged in the enclosed space, an inner crucible and a crucible support are sealed in the outer crucible, the crucible support comprises a first heat conducting portion and a second heat conducting portion with different thermal conductivities, the first heat conducting portion supports a shoulder portion of the inner crucible, and the second heat conducting portion supports the first heat conducting portion; The heater is sleeved on the outer side of the quartz cover and connected to the lead screw of the lead screw lifting machine.

2. The single crystal furnace device according to claim 1, characterized in that: The thermal conductivity of the first heat conducting portion is smaller than the thermal conductivity of the second heat conducting portion.

3. The single crystal furnace device according to claim 2, characterized in that: The thermal conductivity of the first heat-conducting part is 0.05-25 W / mk, and the thermal conductivity of the second heat-conducting part is 0.5-30 W / mk.

4. The single crystal furnace device according to claim 1, characterized in that: The heater is composed of a plurality of sections of heater units, and the plurality of sections of heater units are distributed along the length direction of the heater, and each section of the heater units can be independently controlled.

5. The single crystal furnace device according to claim 1, characterized in that: There are two screw hoists, and the two screw hoists are respectively connected to two sides of the heater; A driving mechanism is provided at the upper end of the furnace body, and the driving mechanism is connected to the two screw hoists.

6. The single crystal furnace device according to claim 5, characterized in that: The driving mechanism comprises a clutch, a first motor and a second motor, one end of the clutch is connected to a first pulley, a first reducer is coaxially connected to the first pulley, and the first reducer is respectively connected to the two screw hoists; A second pulley is provided on the output shaft of the first motor, and the second pulley is connected to the first pulley by a belt; A second speed reducer and a third speed reducer are connected between the second motor and the other end of the clutch.

7. The single crystal furnace device according to any one of claims 1 to 6, characterized in that: A support platform supported on the base is provided in the enclosed space, one end of the second heat conducting part away from the first heat conducting part is inserted into the support platform, and the end surface of one end of the outer crucible connected to the support platform abuts against the upper surface of the support platform.

8. The single crystal furnace device according to any one of claims 1 to 6, characterized in that: The base is provided with a mounting groove, the inner wall of the mounting groove is provided with a sealing ring, the quartz cover is inserted into the mounting groove, and a water cooling channel is provided in the base.

9. The single crystal furnace device according to any one of claims 1 to 6, characterized in that: A slide rail is arranged at the bottom end of the furnace body, and a slider is arranged on the base, and the slider is slidably connected in the slide rail.

10. The single crystal furnace device according to any one of claims 1 to 6, characterized in that: A roller is arranged at the lower end of the furnace body.

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