A device and method for growing indium phosphide single crystal

Abstract

The invention discloses a device and method for growing an indium phosphide single crystal. The device for growing an indium phosphide single crystal comprises a cylinder, a receiving seat, a heater, a crucible support and a quartz tube; the top and bottom of the side wall of the cylinder are respectively provided with upper and lower air holes; two vertical and oppositely arranged guide rails are arranged inside the cylinder; the top and bottom of the cylinder are respectively sealed with upper and lower flange surfaces; the receiving seat is arranged on the lower flange inside the cylinder; the heater is a cylindrical resistance heater with four zones; the two sides of the heater are respectively slidably connected to the two guide rails through connecting pieces; the receiving seat is provided with a motor, and the motor drives the heater to move up and down along the guide rails; the crucible support is installed on the receiving seat and extends from the bottom of the heater into the inner side of the heater, and the heater can move up and down relative to the crucible support; the quartz tube is located on the crucible support inside the heater, and the top of the quartz tube is sealed with a quartz cap. The invention reduces the growth temperature of the single crystal and significantly improves the single crystal quality and crystallization rate.

Description

Technical Field

[0001] The invention relates to a device and a method for growing an indium phosphide single crystal, belonging to the technical field of indium phosphide single crystal growth. Background Art

[0002] Indium phosphide (InP) is one of the important III-V compound semiconductor materials and a new generation of electronic functional materials after Si and GaAs. GaAs, InP and other materials have superior properties that Ge and Si do not have (such as high electron mobility, large bandgap, etc.), and are widely used in the field of microwave and optoelectronic devices. InP materials are suitable for manufacturing millimeter-wave frequency conversion devices and can be widely used in radar communications and precision guidance. InP-based microwave devices are key components of the new generation of satellite communications and precision guidance, which directly determine the rapid response capability of weapon equipment systems.

[0003] At present, the main methods for growing InP single crystals include high-pressure liquid-sealed Czochralski method (LEC), vertical gradient solidification method (VGF) and vertical Bridgman (VB) method, etc. However, the single crystals grown by LEC are of poor quality and high dislocation density, and can generally only be used in the field of light-emitting devices such as LEDs. The VGF crucible does not move, and growth is achieved solely by temperature regulation. Its quality is better than that of LEC, but it requires high temperature control accuracy, is prone to flower crystals, and has a low crystal formation rate. The VB method is similar to the VGF method, except that the temperature field does not move, and the crucible moves downward for growth. The mechanical vibration during the movement of the crucible can easily lead to flower crystals and twins, and the crystal formation rate is low. Summary of the invention

[0004] The present invention provides a device and method for growing an indium phosphide single crystal, which can effectively improve the shortcomings of the current indium phosphide single crystal growth process, such as high dislocation density, low crystallization rate, and high cost.

[0005] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0006] A device for growing an indium phosphide single crystal comprises a cylinder, a receiving seat, a heater, a crucible support and a quartz tube;

[0007] An upper air hole is opened at the top of the side wall of the cylinder, and a lower air hole is opened at the bottom of the side wall of the cylinder, and the upper air hole and the lower air hole are symmetrically arranged;

[0008] Two vertical and oppositely arranged guide rails are provided inside the cylinder;

[0009] The top of the cylinder is sealed with an upper flange surface, and the bottom of the cylinder is sealed with a lower flange surface;

[0010] The receiving seat is arranged on the lower flange in the cylinder;

[0011] The heater is a four-zone cylindrical resistance heater, which is divided into four temperature zones, namely temperature zone 1, temperature zone 2, temperature zone 3 and temperature zone 4 from bottom to top; oppositely arranged connecting pieces are provided on both sides of the heater, and the connecting pieces on both sides of the heater are respectively slidably connected to two guide rails; a motor is provided on the receiving seat, and the motor drives the heater to move up and down along the guide rails;

[0012] The crucible support is installed on the receiving seat and extends from the bottom of the heater into the inner side of the heater. The heater can move up and down relative to the crucible support.

[0013] The quartz tube is located on the crucible support inside the heater, and the top of the quartz tube is sealed with a quartz cap.

[0014] The above device controls the power to grow indium phosphide single crystals by moving the heater, and can grow single crystals at a relatively low temperature (even slightly lower than the melting point of the crystal). It only ensures that the raw materials are in a molten state in a micro-region near the growth interface (the junction of the second temperature zone and the third temperature zone) for growth. The product performance is uniform, and the temperature of each temperature zone remains unchanged during growth. The temperature control is relatively simple and easy to implement, and the crucible does not move, thereby avoiding mechanical vibration of the crucible movement, etc., and can grow indium phosphide crystals with high uniformity, low dislocation density, and long size, and the crystallization rate of indium phosphide crystals is improved.

[0015] In order to facilitate control and simplify the structure, the motor drives the heater to move up and down along the guide rail through a screw rod.

[0016] As one specific implementation scheme, the motor is provided with a screw rod vertically upward, the bottom of the heater is provided with a connecting tube matching the screw rod, the inner side of the connecting tube is provided with an internal thread, and the screw rod on the motor matches the internal thread of the connecting tube. In this way, by controlling the rotation direction of the motor, the heater can be moved up and down.

[0017] In order to improve the operating stability of the device, two synchronous and relatively arranged motors are provided on the receiving seat.

[0018] In order to improve the use stability of the device, the connecting piece is connected to the outer side wall of the heater through a fixing piece.

[0019] In order to further improve the operating stability of the device, the fixing piece is welded to the outer side wall of the heater.

[0020] In order to facilitate installation and ensure stability requirements, the upper surface of the lower flange is a groove structure, and the bottom of the receiving seat is engaged in the groove on the upper surface of the lower flange.

[0021] Preferably, the upper surface of the receiving seat is a groove structure, and the motor and the crucible support are installed in the groove on the upper surface of the receiving seat.

[0022] The material used for the cylinder is 304 stainless steel; the material used for the crucible holder is aluminum silicate ceramic.

[0023] The method for growing an indium phosphide single crystal using the above-mentioned device for growing an indium phosphide single crystal comprises the following steps:

[0024] 1) First, a seed crystal is placed in a seed crystal groove at the bottom of a boron nitride crucible, and then 98-99 parts of indium phosphide polycrystalline material, 0.5-1 part of red phosphorus, 0.5-1 part of anhydrous boron oxide and 0.01-0.05 part of a dopant are placed in the boron nitride crucible, and then the crucible is placed in a quartz tube, covered with a quartz cap, the quartz tube is evacuated, and the quartz tube and the quartz cap are sealed with a hydrogen-oxygen flame; wherein the purity of the indium phosphide polycrystalline material is 6N, the purity of the red phosphorus is 6N, the purity of the anhydrous boron oxide is 6N, the purity of the dopant is 5N, and the purity of the seed crystal is 6N, and the parts are parts by weight;

[0025] 2) Place the sealed quartz tube on the crucible holder, seal the cylinder with the upper and lower flanges, evacuate from the upper and lower air holes, and raise the temperature at the same time. When the vacuum degree is ≤-0.9MPa and the temperature is ≥350°C, introduce nitrogen into the cylinder through the upper and lower air holes, adjust the pressure in the cylinder to 1.8-2.0MPa in 25-35min, and raise the temperature in the quartz tube to 640-660°C at a rate of 8-10°C / min;

[0026] 3) Continue to increase the temperature at a rate of 8-10°C / min, control the set temperature so that the temperature of temperature zone 1 and temperature zone 2 is 1000-1050°C, the temperature of temperature zone 3 and temperature zone 4 is 1050-1100°C, the temperature gradient of 1 inch above and below the junction of temperature zone 2 and temperature zone 3 (initial growth interface) is 4-6°C / cm, and the temperature gradient outside the 1 inch range of the junction is 0-4°C / cm;

[0027] 4) After maintaining the constant temperature for 24 hours, turn on the motor to make the heater move upward at a constant speed of 1 to 2 cm / h to grow the single crystal until the single crystal growth is completed;

[0028] 5) After the single crystal growth is completed, the temperature of each temperature zone is controlled to drop to 100-150°C at a cooling rate of 8-30°C / h, the gas in the single crystal furnace is discharged, the upper and lower flanges are opened, and the quartz tube and single crystal rod are taken out.

[0029] In the above step 4), only the upward movement is performed, and the single crystal growth is completed during the upward movement.

[0030] The technologies not mentioned in the present invention are all referred to the prior art.

[0031] The device for growing an indium phosphide single crystal of the present invention controls the power by moving a heater to grow the indium phosphide single crystal, can grow the single crystal at a relatively low temperature, only ensures that the raw material in the micro-region near the growth interface is in a molten state for growth, the product performance is uniform, the temperature of each temperature zone remains unchanged during growth, the temperature control is relatively simple and easy to achieve, and the crucible does not move, thereby avoiding mechanical vibration of the crucible movement, etc., can grow indium phosphide crystals with high uniformity, low dislocation density and long size, and improves the crystallization rate of the indium phosphide crystals; through the mobile heater method combined with the growth method of the present application, even zero dislocation is achieved, the length of the grown crystal rod can reach 200 mm, which is more than twice that of the existing method, the crystallization rate can reach more than 92%, while the existing method is only about 60%, and the uniformity of the crystal rod is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of a device for growing an indium phosphide single crystal according to the present invention;

[0033] In the figure, 1, cylinder, 2, upper air hole, 3, lower air hole, 4, upper flange, 5, lower flange, 6, heater (four temperature zones), 601, temperature zone one, 602, temperature zone two, 603, temperature zone three, 604, temperature zone four, 7, guide rail, 8, fixing part, 9, connecting part, 10, socket, 11, connecting cylinder, 12, motor, 13, crucible support, 14, quartz tube, 15, quartz cap. DETAILED DESCRIPTION

[0034] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0035] In this application, directional words such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings or in use, and are only for the convenience of describing this application, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0036] Example 1

[0037] like Figure 1 As shown, a device for growing an indium phosphide single crystal comprises a cylinder, a receiving seat, a heater, a crucible support and a quartz tube;

[0038] An upper air hole is opened at the top of the side wall of the cylinder, and a lower air hole is opened at the bottom of the side wall of the cylinder, and the upper air hole and the lower air hole are symmetrically arranged;

[0039] Two vertical and oppositely arranged guide rails are provided inside the cylinder;

[0040] The top of the cylinder is sealed with an upper flange surface, and the bottom of the cylinder is sealed with a lower flange surface;

[0041] The receiving seat is arranged on the lower flange in the cylinder;

[0042] The heater is a four-zone cylindrical resistance heater, which is divided into four temperature zones, namely temperature zone 1, temperature zone 2, temperature zone 3 and temperature zone 4 from bottom to top; oppositely arranged connecting pieces are provided on both sides of the heater, and the connecting pieces on both sides of the heater are respectively slidably connected to two guide rails; a motor is provided on the receiving seat, and the motor drives the heater to move up and down along the guide rails;

[0043] The crucible support is installed on the receiving seat and extends from the bottom of the heater into the inner side of the heater. The heater can move up and down relative to the crucible support.

[0044] The quartz tube is located on the crucible support inside the heater, and the top of the quartz tube is sealed with a quartz cap.

[0045] The above device controls the power to grow indium phosphide single crystals by moving the heater, and can grow single crystals at a relatively low temperature (even slightly lower than the melting point of the crystal). It only ensures that the raw materials are in a molten state in a micro-region near the growth interface (the junction of the second temperature zone and the third temperature zone) for growth. The product performance is uniform, and the temperature of each temperature zone remains unchanged during growth. The temperature control is relatively simple and easy to implement, and the crucible does not move, thereby avoiding mechanical vibration of the crucible movement, etc., and can grow indium phosphide crystals with high uniformity, low dislocation density, and long size, and the crystallization rate of indium phosphide crystals is improved.

[0046] Example 2

[0047] On the basis of Example 1, the following improvements are further made: in order to facilitate control and simplify the structure, the motor drives the heater to move up and down along the guide rail through a screw rod. The motor is provided with a screw rod arranged vertically upward, and a connecting cylinder matching the screw rod is provided at the bottom of the heater. The inner side of the connecting cylinder is provided with an internal thread, and the screw rod on the motor cooperates with the internal thread of the connecting cylinder. In this way, by controlling the rotation direction of the motor, the up and down movement of the heater can be realized.

[0048] Example 3

[0049] On the basis of Example 2, the following improvements are further made: in order to improve the operating stability of the device, two synchronous and relatively arranged motors are provided on the receiving seat.

[0050] Example 4

[0051] On the basis of Example 3, the following improvements are further made: In order to improve the stability of the device, the connecting piece is connected to the outer wall of the heater through a fixing piece. In order to further improve the stability of the device, the fixing piece is welded to the outer wall of the heater.

[0052] Example 5

[0053] On the basis of Example 4, the following improvements are further made: in order to facilitate the following and ensure the stability requirements, the upper surface of the lower flange is a groove structure, and the bottom of the receiving seat is engaged in the groove on the upper surface of the lower flange. The upper surface of the receiving seat is a groove structure, and the motor and the crucible holder are installed in the groove on the upper surface of the receiving seat. The material used for the above-mentioned cylinder is 304 stainless steel; the material used for the crucible holder is aluminum silicate ceramic.

[0054] The method for growing an indium phosphide single crystal using the above device comprises the following steps:

[0055] 1. Load the seed crystal (6N) into the seed crystal groove at the bottom of the boron nitride crucible, then load the indium phosphide polycrystalline material (6N, 6000g), red phosphorus (6N, 50g), anhydrous boron oxide (6N, 50g) and dopant S (5N, 1g) and the seed crystal (6N) into the boron nitride crucible, then put the crucible into a quartz tube, cover it with a quartz cap, evacuate the quartz tube, and use a hydrogen-oxygen flame to seal the quartz tube and the quartz cap;

[0056] 2. Place the sealed quartz tube on the crucible holder, seal it with the upper and lower flanges, evacuate from the upper and lower air holes, and raise the temperature at the same time. When the vacuum degree is ≤-0.9MPa and the temperature is ≥350℃, introduce nitrogen into the cylinder through the upper and lower air holes. Adjust the pressure in the furnace to 1.8MPa in about 30 minutes, and raise the temperature to 650℃ at a rate of 10℃ / min.

[0057] 3. Continue to increase the temperature at a rate of 10°C / min, control the set temperature to make the temperature of temperature zone 1 and temperature zone 2 at 1020°C, the temperature of temperature zone 3 and temperature zone 4 at 1080°C, the temperature gradient of 1 inch above and below the junction of temperature zone 2 and temperature zone 3 (initial growth interface) at 6°C / cm, and the temperature gradient outside the 1 inch range of the junction at 3°C / cm;

[0058] 4. After keeping the temperature constant for 24 hours, turn on the motor to make the heater move upward at a constant speed of 1.5 cm / h to grow the single crystal until the single crystal growth is completed;

[0059] 5. After the single crystal growth is completed, control the temperature of each temperature zone to drop to 150°C at a cooling rate of 15°C / h, discharge the gas in the single crystal furnace, open the upper and lower flanges, and take out the quartz tube and single crystal rod;

[0060] The length of the obtained single crystal rod is 200mm. The Hall test and dislocation corrosion are carried out on the obtained single crystal rod. The head CC (carrier concentration) value is measured to be 2.72E+18, and the M (electron mobility) value is 2116m 2 ·V -1 ·s -1 , R (resistivity) value is 1.62E-3Ω·m, dislocation density is 0 / cm 2 The tail CC (carrier concentration) value is 3.02E+18, and the M (electron mobility) value is 2023m 2 ·V -1 ·s -1 , R (resistivity) value is 1.59E-3Ω·m, dislocation density is 3 / cm 2 , the crystallization rate is 95%.

Claims

1. A method for growing an indium phosphide single crystal, characterized in that: The device for growing indium phosphide single crystals comprises a cylinder, a receiving seat, a heater, a crucible holder and a quartz tube; an upper air hole is provided on the top of the side wall of the cylinder, a lower air hole is provided on the bottom of the side wall of the cylinder, and the upper and lower air holes are symmetrically arranged; two vertical and oppositely arranged guide rails are provided on the inner side of the cylinder; the top of the cylinder is sealed with an upper flange surface, and the lower part of the cylinder is sealed with a lower flange surface; the receiving seat is provided on the lower flange of the cylinder; the heater is a four-zone cylindrical resistance heater, and the heater is divided into four temperature zones, which are temperature zone one, temperature zone two, temperature zone three and temperature zone four from bottom to top; oppositely arranged connecting pieces are provided on both sides of the heater, and the connecting pieces on both sides of the heater are slidably connected to the two guide rails respectively; a motor is provided on the receiving seat, and the motor drives the heater to move up and down along the guide rails; the crucible holder is installed on the receiving seat and extends into the inner side of the heater from the bottom of the heater, and the heater can move up and down relative to the crucible holder; the quartz tube is located on the crucible holder inside the heater, and the top of the quartz tube is sealed with a quartz cap; A method for growing an indium phosphide single crystal comprises the following steps: 1) First, a seed crystal is placed in a seed crystal groove at the bottom of a boron nitride crucible. Then, 98-99 parts of an indium phosphide polycrystalline material, 0.5-1 part of red phosphorus, 0.5-1 part of anhydrous boron oxide, and 0.01-0.05 part of a dopant S are placed in the boron nitride crucible. The crucible is then placed in a quartz tube, covered with a quartz cap, the quartz tube is evacuated, and the quartz tube and the quartz cap are sealed with an oxyhydrogen flame. The purity of the indium phosphide polycrystalline material is 6N, the purity of the red phosphorus is 6N, the purity of the anhydrous boron oxide is 6N, the purity of the dopant is 5N, and the purity of the seed crystal is 6N. The parts are by weight. 2) Place the sealed quartz tube on the crucible holder, seal the cylinder with the upper and lower flanges, evacuate from the upper and lower air holes, and simultaneously increase the temperature. When the vacuum degree is ≤-0.9 MPa and the temperature is ≥350°C, introduce nitrogen into the cylinder through the upper and lower air holes. Adjust the pressure in the cylinder to 1.8-2.0 MPa over 25-35 minutes, and simultaneously increase the temperature in the quartz tube to 640-660°C at a rate of 8-10°C / min. 3) Continue heating at a rate of 8-10°C / min, control the set temperature so that the temperature of temperature zone 1 and temperature zone 2 is between 1000-1050°C, the temperature of temperature zone 3 and temperature zone 4 is between 1050-1100°C, the temperature gradient of 1 inch above and below the junction of temperature zone 2 and temperature zone 3 is between 4-6°C / cm, and the temperature gradient of 1 inch beyond the junction is between 0-4°C / cm; 4) After maintaining the constant temperature for 24 hours, turn on the motor and move the heater upward at a constant speed of 1 to 2 cm / h to grow the single crystal until the single crystal growth is completed; 5) After the single crystal growth is completed, control the temperature of each temperature zone to drop to 100-150°C at a cooling rate of 8-30°C / h, exhaust the gas in the single crystal furnace, open the upper and lower flanges, and take out the quartz tube and single crystal rod.

2. The method for growing an indium phosphide single crystal according to claim 1, wherein: The motor drives the heater to move up and down along the guide rail through the lead screw.

3. The method for growing an indium phosphide single crystal according to claim 2, wherein: The motor is provided with a screw rod arranged vertically upward, the bottom of the heater is provided with a connecting tube matching the screw rod, the inner side of the connecting tube is provided with an internal thread, and the screw rod on the motor cooperates with the internal thread of the connecting tube.

4. The method for growing an indium phosphide single crystal according to any one of claims 1 to 3, wherein: The receiving seat is provided with two synchronous motors that are arranged opposite to each other.

5. The method for growing an indium phosphide single crystal according to any one of claims 1 to 3, wherein: The connecting piece is connected to the outer side wall of the heater through a fixing piece.

6. The method for growing an indium phosphide single crystal according to claim 5, wherein: The fixing piece is welded to the outer side wall of the heater.

7. The method for growing an indium phosphide single crystal according to any one of claims 1 to 3, wherein: The upper surface of the lower flange is a groove structure, and the bottom of the receiving seat is engaged in the groove on the upper surface of the lower flange.

8. The method for growing an indium phosphide single crystal according to any one of claims 1 to 3, wherein: The upper surface of the receiving seat is a groove structure, and the motor and the crucible support are installed in the groove on the upper surface of the receiving seat.

9. The method for growing an indium phosphide single crystal according to any one of claims 1 to 3, wherein: The material used for the cylinder is 304 stainless steel; the material used for the crucible holder is aluminum silicate ceramic.

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