High-uniformity indium phosphide crystal growth method

Abstract

The invention discloses a high-uniformity indium phosphide crystal growth method, which comprises the following steps in a crystal growth stage: gradient cooling control: reducing the temperature of a lower area of a heating furnace at a rate of 0.1-0.3 DEG C / h, keeping the temperature of an upper area of the heating furnace unchanged at 1070 DEG C, forming a temperature gradient from top to bottom, controlling the axial temperature difference at 10-15 DEG C / cm, and inducing melt to start to solidify from the bottom of a crucible; applying a weak magnetic field: in the growth process, applying an axial weak direct-current magnetic field to a melt area, controlling the magnetic field intensity to be 0.1-0.2 T, inhibiting natural convection of the melt through Lorentz force, and stabilizing a solid-liquid interface; interface monitoring: monitoring the temperature of a solid-liquid interface in real time through an infrared thermometer on the side surface of the furnace body, and when the interface temperature deviates from 1070 + / -0.5 DEG C, automatically adjusting the cooling rate of a lower area to ensure that the interface is in a horizontal state; the dislocation density of the obtained high-uniformity indium phosphide crystal is less than or equal to 10cm; the radial resistivity fluctuation is less than or equal to 3%; the purity is greater than or equal to 99.9999%. According to the method, the dislocation density of the indium phosphide crystal is effectively reduced, the radial resistivity fluctuation is reduced, and the uniformity is improved.

Description

Technical Field

[0001] This invention relates to a method for growing highly uniform indium phosphide crystals, belonging to the field of semiconductor material preparation technology. Background Technology

[0002] The current mainstream technologies for indium phosphide crystal growth mainly include the liquid-sealed Czochralski (LEC) method and the vertical gradient solidification (VGF) method. The core principle of both methods is to achieve single crystal growth by controlling the cooling of the melt. The specific status is as follows:

[0003] LEC method: Using boron oxide (B2O3) as a liquid encapsulant, single crystals are pulled from the melt under high pressure and inert gas environment, which can achieve the growth of large-size (4-6 inches) crystals. However, there are two major problems: First, the temperature gradient during the growth process is large (axial temperature difference can reach 50-80℃ / cm), which leads to significant thermal stress inside the crystal, and the final dislocation density is as high as 10. 4 -10 5 cm⁻²; secondly, the liquid sealant is prone to react with the crucible, introducing boron impurities and affecting the electrical properties of the crystal.

[0004] VGF method: By slowly reducing the temperature gradient in the heating furnace, the melt solidifies from the bottom up. This method can reduce the temperature gradient (axial temperature difference ≤ 30℃ / cm) and decrease the dislocation density (which can be reduced to 10). 2 -10 3 However, there is a problem of unstable melt convection. During the growth process, the melt generates natural convection due to density differences, resulting in uneven distribution of indium and phosphorus components (component deviation can reach 0.5%-1%). In addition, the solid-liquid interface is prone to convexity, which causes fluctuations in the radial resistivity of the crystal.

[0005] In summary, the core defect of the existing technology stems from the contradiction between "temperature gradient control" and "melt convection suppression," which cannot simultaneously meet the requirements of low crystal defects and high uniformity, thus restricting the application of indium phosphide in high-performance optical communication chips and quantum devices. Summary of the Invention

[0006] This invention provides a method for growing indium phosphide crystals with high uniformity, which effectively reduces the dislocation density of indium phosphide crystals, reduces radial resistivity fluctuations, and improves uniformity.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for growing highly uniform indium phosphide crystals includes the following operations during the crystal growth stage:

[0009] Gradient cooling control: The temperature of the lower zone of the heating furnace is reduced at a rate of 0.1-0.3℃ / h, while the temperature of the upper zone is kept constant at 1070℃, forming a temperature gradient from top to bottom. The axial temperature difference is controlled at 10-15℃ / cm, inducing the melt to solidify from the bottom of the crucible.

[0010] Weak magnetic field application: During the growth process, a weak axial DC magnetic field is applied to the melt region, with the magnetic field strength controlled at 0.1-0.2T. The natural convection of the melt is suppressed by the Lorentz force, stabilizing the solid-liquid interface.

[0011] Interface monitoring: The solid-liquid interface temperature is monitored in real time by an infrared thermometer on the side of the furnace. When the interface temperature deviates from 1070±0.5℃, the cooling rate of the lower zone is automatically adjusted to ensure that the interface is horizontal.

[0012] The obtained highly uniform indium phosphide crystals have a dislocation density ≤10cm⁻², an indium to phosphorus atomic ratio deviation ≤0.1%, a radial resistivity fluctuation ≤3%, and a purity ≥99.9999%.

[0013] To further improve the product quality of the obtained indium phosphide crystals, a staged melting process is adopted during the raw material melting stage:

[0014] First stage: Increase the temperature to 500℃ at a rate of 5-8℃ / min, hold for 1.5-2 hours, and further degas;

[0015] Second stage: Increase the temperature to 800℃ at a rate of 2-3℃ / min, and hold for 0.5-1 hour to avoid local overheating of the raw materials;

[0016] The third stage: Heat the material to 1070-1075℃ (the melting point of indium phosphide) at a rate of 1-1.5℃ / min, and hold for 3-4 hours to ensure that the raw materials are completely melted and form a uniform melt.

[0017] To further improve the product quality of the obtained indium phosphide crystals, annealing and cooling were performed after growth, following the procedure below:

[0018] Annealing treatment: After the crystal has completely solidified (growth time 100-120 hours), the furnace body is cooled to 600℃ at a rate of 0.5℃ / h and held for 24 hours to release the internal thermal stress of the crystal.

[0019] Cooling and demolding: After annealing, cool to room temperature at a rate of 2-3℃ / h, open the quartz sealing tube, take out the crucible and peel off the BN coating to obtain indium phosphide single crystal ingot.

[0020] As one preferred implementation, the method for growing highly uniform indium phosphide crystals includes the following steps:

[0021] 1) Raw material pretreatment:

[0022] Raw material composition: Indium phosphide polycrystalline material and dopant, with a molar ratio of indium phosphide polycrystalline material to dopant of 100:(0.01-0.05);

[0023] Pretreatment: Place the raw materials in a vacuum baking oven at a temperature of 200-250℃ and a vacuum degree of 1×10⁻ 4 Baking under Pa conditions for 4-6 hours removes moisture and oxygen adsorbed on the surface of the raw materials;

[0024] 2) Preparation of crucible and apparatus:

[0025] Crucible selection: Use high-purity quartz crucibles with a 5-10μm thick boron nitride (BN) coating on the inner wall to prevent the melt from reacting with the quartz;

[0026] Device assembly: Place the coated crucible into a dual-zone heating furnace. The furnace is equipped with an axial temperature control system, and a radial weak magnetic field generator is set around the axial temperature control system.

[0027] 3) Loading and vacuum sealing:

[0028] Loading operation: In an inert gas glove box, the pretreated raw materials and dopants are loaded into a quartz crucible, covered and then placed into a quartz sealing tube;

[0029] Vacuum sealing: Evacuate the quartz sealing tube until the vacuum level is ≤5×10⁻ 5 After Pa, the two ends of the sealing tube are melted and sealed using an oxyhydrogen flame;

[0030] 4) Staged heating and melting:

[0031] First stage: Increase the temperature to 500℃ at a rate of 5-8℃ / min, hold for 1.5-2 hours, and further degas;

[0032] Second stage: Increase the temperature to 800℃ at a rate of 2-3℃ / min, and hold for 0.5-1 hour to avoid local overheating of the raw materials;

[0033] The third stage: Heat to 1070-1075℃ (indium phosphide melting point) at a rate of 1-1.5℃ / min, and hold for 3-4 hours to ensure that the raw materials are completely melted and form a uniform melt;

[0034] 5) Crystal growth:

[0035] Gradient cooling control: The temperature of the lower zone of the heating furnace is reduced at a rate of 0.1-0.3℃ / h, while the temperature of the upper zone is kept constant at 1070℃, forming a temperature gradient from top to bottom. The axial temperature difference is controlled at 10-15℃ / cm, inducing the melt to solidify from the bottom of the crucible.

[0036] Weak magnetic field application: During the growth process, a weak axial DC magnetic field is applied to the melt region, with the magnetic field strength controlled at 0.1-0.2T. The natural convection of the melt is suppressed by the Lorentz force, stabilizing the solid-liquid interface.

[0037] Interface monitoring: The solid-liquid interface temperature is monitored in real time by an infrared thermometer on the side of the furnace. When the interface temperature deviates from 1070±0.5℃, the cooling rate of the lower zone is automatically adjusted to ensure that the interface is horizontal.

[0038] 6) Annealing and cooling:

[0039] Annealing treatment: After the crystal has completely solidified (growth time 100-120 hours), the furnace body is cooled to 600℃ at a rate of 0.5℃ / h and held for 24 hours to release the internal thermal stress of the crystal.

[0040] Cooling and demolding: After annealing, cool to room temperature at a rate of 2-3℃ / h, open the quartz sealing tube, take out the crucible and peel off the BN coating to obtain indium phosphide single crystal ingot.

[0041] The above method employs a "vacuum sealing, gradient temperature control, and weak magnetic field synergy" indium phosphide crystal growth approach, effectively solving the following technical problems:

[0042] 1) The dislocation density of indium phosphide crystal was reduced, solving the crystal defect problem caused by thermal stress in the existing technology, and achieving a dislocation density of ≤10 cm⁻².

[0043] 2) Suppress natural convection of the melt, improve the uniformity of crystal composition, and make the indium-phosphorus atomic ratio deviation ≤0.1% and the radial resistivity fluctuation ≤3%.

[0044] 3) It reduces the introduction of impurities, avoids the reaction and contamination between the liquid sealant and the crucible, and ensures crystal purity (electronic grade purity ≥ 99.9999%).

[0045] 4) Optimize the solid-liquid interface shape to avoid unstable crystal growth caused by convex interface and achieve controllable growth at flat interfaces.

[0046] To further improve the purity of the obtained indium phosphide crystals, in step 1) above, the purity of the polycrystalline indium phosphide is 99.9999%; the dopant is indium sulfide or zinc with a purity of 99.999%.

[0047] To further improve the purity of the obtained indium phosphide crystals, in step 2) above, the purity of the high-purity quartz crucible is 99.999%.

[0048] To further improve the product quality of the obtained indium phosphide crystals, the temperature control system accuracy in step 2) above is ±0.5℃.

[0049] In step 3) above, the inert gas glove box contains a high-purity argon atmosphere with a purity of 99.999%.

[0050] This invention is particularly suitable for the large-scale preparation of high-purity, low-defect-density indium phosphide crystals.

[0051] The highly uniform indium phosphide crystals obtained by this invention can be used in optoelectronic devices, microwave devices, etc.

[0052] Any techniques not mentioned in this invention are based on existing technologies.

[0053] This invention, through a synergistic design of "gradient temperature control combined with a weak magnetic field," possesses the following core advantages compared to existing LEC and VGF methods:

[0054] Defect density is significantly reduced: With the axial temperature difference controlled at 10-15℃ / cm and combined with long-term annealing at 600℃, the crystal dislocation density can be reduced to ≤10 cm⁻², which is more than 3 orders of magnitude lower than the LEC method and more than 1 order of magnitude lower than the traditional VGF method.

[0055] Improved uniformity of composition and electrical properties: The weak magnetic field of 0.1-0.2T effectively suppresses melt convection, the atomic ratio deviation of indium and phosphorus is ≤0.1%, and the radial resistivity fluctuation is ≤3%, which is far superior to the 0.5% and 5% of the traditional VGF method.

[0056] Improved production stability: Controllable growth at planar interfaces increases the crystal yield from 60%-70% in traditional methods to 85%-90%, and the growth process does not require a high-pressure environment, reducing equipment costs and operational risks. Attached Figure Description

[0057] Figure 1 A schematic diagram showing the relative positions of the crucible, the axial temperature control system, and the radial weak magnetic field generator;

[0058] In the figure, 1 is the crucible, 2 is the axial temperature control system, and 3 is the radial weak magnetic field generator. Detailed Implementation

[0059] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0060] Example 1: Growth of sulfur-doped indium phosphide crystals (N-type semiconductor)

[0061] 1) Raw material pretreatment:

[0062] Raw materials: 37.73 mol of indium phosphide polycrystalline material (approximately 5.5 kg, purity 99.9999%), and 0.0035 mol of indium sulfide dopant (approximately 1.14 g, purity 99.999%).

[0063] Raw material pretreatment: Place the raw materials in a vacuum baking oven at a temperature of 220℃ and a vacuum degree of 1×10⁻ 4 Bake for 5 hours under Pa conditions.

[0064] 2) Preparation of crucible and apparatus:

[0065] Crucible: Quartz crucible (99.999% purity), 100mm inner diameter (suitable for 4-inch crystals), BN coating thickness of 8μm on the inner wall of the quartz crucible.

[0066] Device assembly: Place the quartz crucible into the dual-zone heating furnace. The furnace is equipped with an axial temperature control system (accuracy ±0.5℃) and a radial weak magnetic field generator (magnetic field strength adjustable range 0.05-0.3T).

[0067] 3) Loading and vacuum sealing:

[0068] Loading procedure: In an inert gas (high-purity argon, 99.999% purity) glove box, the pretreated raw materials and sulfur dopant are loaded into a quartz crucible, covered, and then placed into a quartz sealing tube.

[0069] Vacuum sealing: Evacuate the quartz sealing tube until the vacuum level is ≤5×10⁻ 5 After Pa, the two ends of the sealing tube are fused together using an oxyhydrogen flame.

[0070] 4) Staged heating and melting:

[0071] First stage: Increase the temperature to 500℃ at a rate of 6℃ / min, hold for 2 hours, and further degas;

[0072] Second stage: Heat to 800℃ at a rate of 2.5℃ / min and hold for 1 hour to avoid local overheating of the raw materials;

[0073] The third stage: the temperature is increased to 1072℃ at a rate of 12℃ / min and held for 3.5 hours to ensure that the raw materials are completely melted and a uniform melt is formed.

[0074] 5) Crystal growth:

[0075] Gradient cooling control: The temperature of the lower zone of the heating furnace is reduced at a rate of 0.2℃ / h (the temperature of the upper zone is kept constant at 1072℃) to form a temperature gradient from top to bottom (axial temperature difference is controlled at 10-15℃ / cm), which induces the melt to solidify from the bottom of the crucible.

[0076] Weak magnetic field application: During the growth process, a weak axial DC magnetic field is applied to the melt region, with the magnetic field strength controlled at 0.15T. The natural convection of the melt is suppressed by the Lorentz force, stabilizing the solid-liquid interface.

[0077] Interface monitoring: The solid-liquid interface temperature is monitored in real time by an infrared thermometer on the side of the furnace. When the interface temperature deviates from 1070±0.5℃, the cooling rate of the lower zone is automatically adjusted to ensure that the interface is flat.

[0078] 6) Annealing and cooling:

[0079] Annealing treatment: After the crystal has completely solidified, the furnace body is cooled to 600℃ at a rate of 0.5℃ / h and held for 24 hours to release the internal thermal stress of the crystal.

[0080] Cooling and demolding: After annealing, the temperature is reduced to room temperature at a rate of 2.5℃ / h. The quartz sealing tube is opened, the crucible is removed, and the BN coating is peeled off to obtain an indium phosphide single crystal ingot.

[0081] Indium phosphide single crystal ingot product properties: single crystal ingot length 120mm, dislocation density 5 cm⁻², resistivity (0.8-1.0)E -3 Ω・cm (radial fluctuation 2.8%), sulfur impurity content 8×10¹ 5 atoms / cm³.

[0082] Example 2: Zinc-doped indium phosphide crystal growth (P-type semiconductor)

[0083] Raw materials: 37.70 mol indium phosphide polycrystalline material, 0.007 mol zinc dopant (approximately 0.46 g), pretreatment conditions: 240℃, 1×10⁻ 4 Bake for 4.5 hours.

[0084] Crucible: Same as in Example 1, with a BN coating thickness of 7 μm.

[0085] The third stage of the melting process involves heating to 1074℃ and holding at that temperature for 4 hours.

[0086] During the gradient cooling control stage, the cooling rate during the growth stage is 0.15℃ / h;

[0087] During the application of a weak magnetic field, the magnetic field strength is 0.2T.

[0088] The rest are the same as in Example 1.

[0089] Properties of indium phosphide single crystal ingots: Ingot length 115mm, dislocation density 3 cm⁻², resistivity 0.315-0.330 Ω・cm (radial fluctuation 1.6%), zinc impurity content 1.2×10¹ 6 atoms / cm³.

[0090] Example 3: Growth of undoped high-purity indium phosphide crystals

[0091] Raw material: 37.68 mol of polycrystalline indium phosphide (doped), pretreatment conditions: 250℃, 1×10⁻ 4 Bake for 6 hours.

[0092] Crucible: Same as in Example 1, with a BN coating thickness of 10 μm.

[0093] The third stage of the melting process involves heating to 1070℃ and holding for 3 hours.

[0094] During the gradient cooling control stage, the cooling rate during the growth stage is 0.3℃ / h;

[0095] During the application of a weak magnetic field, the magnetic field strength was 0.1T.

[0096] The rest are the same as in Example 1.

[0097] Performance characteristics of indium phosphide single crystal ingots: ingot length 118 mm, dislocation density 6 cm⁻², resistivity 0.545-0.556 Ω・cm (radial fluctuation 2.0%), total impurity content ≤5×10¹ 5 atoms / cm³.

[0098] Comparative Example 1

[0099] The difference from Example 1 is that the gradient cooling control step is omitted in the crystal growth stage, while the rest is the same as in Example 1.

[0100] Finished product performance: single crystal ingot length 120mm, dislocation density 28cm⁻², resistivity (8.66-9.63)E-4Ω・cm (radial fluctuation 10.07%), sulfur impurity content 7.39E+15atoms / cm³.

[0101] Comparative Example 2

[0102] The difference from Example 1 is that the step of applying a weak magnetic field is omitted in the crystal growth stage, while the rest is the same as in Example 1.

[0103] Finished product performance: single crystal ingot length 118mm, dislocation density 23cm⁻², resistivity (8.66-9.51)E-4)Ω・cm (radial fluctuation 8.94%), sulfur impurity content 7.30E+15atoms / cm³.

[0104] Comparative Example 3

[0105] The difference from Example 1 is that the interface monitoring step is omitted during the crystal growth stage; otherwise, it is the same as Example 1.

[0106] Finished product performance: single crystal ingot length 120mm, dislocation density 49cm⁻², resistivity (0.864-0.988)E-4Ω・cm (radial fluctuation 12.55%), sulfur impurity content 8.57E15atoms / cm³.

[0107] Comparative Example 4

[0108] The difference from Example 1 is that in the staged heating and melting stage, the heating rate of the third stage is 3°C / min, and the rest is the same as in Example 1.

[0109] Finished product performance: single crystal ingot length 115mm, dislocation density 33cm⁻², resistivity (0.855-0.958)E-4Ω・cm (radial fluctuation 10.75%), sulfur impurity content 8.01E15atoms / cm³.

[0110] Comparative Example 5

[0111] The difference from Example 1 is that the heating rate in the third stage of the phased heating and melting stage is 0.5℃ / min, while the rest is the same as in Example 1.

[0112] Finished product performance: single crystal ingot length 117mm, dislocation density 41cm⁻², resistivity (0.866-0.955)E-4Ω・cm (radial fluctuation 9.32%), sulfur impurity content 8.44E15atoms / cm³.

[0113] Comparative Example 6

[0114] The difference from Example 1 is that in the staged heating and melting stage, the heating rate of the second stage is 5°C / min, and the rest is the same as in Example 1.

[0115] Finished product performance: single crystal ingot length 119mm, dislocation density 26cm⁻², resistivity (0.87-0.978)E-4Ω・cm (radial fluctuation 11.04%), sulfur impurity content 8.14E15atoms / cm³.

[0116] Comparative Example 7

[0117] The difference from Example 1 is that in the staged heating and melting stage, the heating rate of the second stage is 1℃ / min, and the rest is the same as in Example 1.

[0118] Finished product performance: single crystal ingot length 118mm, dislocation density 24cm⁻², resistivity (0.865-0.987)E-4Ω・cm (radial fluctuation 12.36%), sulfur impurity content 7.42E15atoms / cm³.

[0119] Comparative Example 8

[0120] The difference from Example 1 is that the second stage of the phased heating and melting process has a final temperature of 950°C, while the rest is the same as in Example 1.

[0121] Finished product performance: single crystal ingot length 120mm, dislocation density 15cm⁻², resistivity (0.857-0.973)E-4Ω・cm (radial fluctuation 11.92%), sulfur impurity content 7.34E15atoms / cm³.

[0122] Comparative Example 9

[0123] The difference from Example 1 is that the second stage of the phased heating and melting process has a final temperature of 650°C, while the rest is the same as in Example 1.

[0124] Finished product performance: single crystal ingot length 118mm, dislocation density 36cm⁻², resistivity (0.863-0.968)E-4Ω・cm (radial fluctuation 10.85%), sulfur impurity content 7.3E15atoms / cm³.

[0125] Comparative Example 10

[0126] The difference from Example 1 is that in the staged heating and melting stage, the heating rate in the first stage is 10°C / min, and the rest is the same as in Example 1.

[0127] Finished product performance: single crystal ingot length 119mm, dislocation density 43cm⁻², resistivity (0.864-0.966)E-4Ω・cm (radial fluctuation 10.56%), sulfur impurity content 7.25E15atoms / cm³.

[0128] Comparative Example 11

[0129] The difference from Example 1 is that in the staged heating and melting stage, the heating rate in the first stage is 3°C / min, and the rest is the same as in Example 1.

[0130] Finished product performance: single crystal ingot length 116mm, dislocation density 50cm⁻², resistivity (0.854-0.969)E-4Ω・cm (radial fluctuation 11.87%), sulfur impurity content 8.79E15atoms / cm³.

[0131] Comparative Example 12

[0132] The difference from Example 1 is that in the staged heating and melting stage, the final temperature of the first stage is 650°C, and the rest is the same as in Example 1.

[0133] Finished product performance: single crystal ingot length 118mm, dislocation density 18cm⁻², resistivity (0.862-1)E-4Ω・cm (radial fluctuation 13.8%), sulfur impurity content 7.31E15atoms / cm³.

[0134] Comparative Example 13

[0135] The difference from Example 1 is that the phased heating and melting stage has a final temperature of 350°C in the first stage, while the rest is the same as in Example 1.

[0136] Finished product performance: single crystal ingot length 119mm, dislocation density 41cm⁻², resistivity (0.856-0.993)E-4Ω・cm (radial fluctuation 13.8%), sulfur impurity content 8.68E15atoms / cm³.

[0137] Comparative Example 14

[0138] The difference from Example 1 is that, in gradient cooling control, the temperature of the lower zone of the heating furnace is reduced at a rate of 0.05℃ / h, while the rest is the same as in Example 1.

[0139] Finished product performance: single crystal ingot length 119mm, dislocation density 49cm⁻², resistivity (0.853-0.989)E-4Ω・cm (radial fluctuation 13.75%), sulfur impurity content 7.99E15atoms / cm³.

[0140] Comparative Example 15

[0141] The difference from Example 1 is that, in gradient cooling control, the temperature of the lower zone of the heating furnace is reduced at a rate of 0.5℃ / h, while the rest is the same as in Example 1.

[0142] Finished product performance: single crystal ingot length 119mm, dislocation density 18cm⁻², resistivity (0.867-0.951)E-4Ω・cm (radial fluctuation 8.83%), sulfur impurity content 7.99E15atoms / cm³.

[0143] Comparative Example 16

[0144] The difference from Example 1 is that when a weak magnetic field is applied, the magnetic field strength is controlled at 0.05T, while the rest is the same as in Example 1.

[0145] Finished product performance: single crystal ingot length 117mm, dislocation density 19cm⁻², resistivity (0.858-0.975)E-4Ω・cm (radial fluctuation 12%), sulfur impurity content 7.91E15atoms / cm³.

[0146] Comparative Example 17

[0147] The difference from Example 1 is that when a weak magnetic field is applied, the magnetic field strength is controlled at 0.3T, while the rest is the same as in Example 1.

[0148] Finished product performance: single crystal ingot length 115mm, dislocation density 18cm⁻², resistivity (0.862-0.976)E-4Ω・cm (radial fluctuation 11.68%), sulfur impurity content 8.63E15atoms / cm³.

Claims

1. A method for growing a high uniformity indium phosphide crystal, the method comprising: In the crystal growth stage, the following operations are performed: ​ Gradient cooling control: reduce the lower zone temperature of the heating furnace at a rate of 0.1-0.3℃ / h, keep the upper zone temperature at 1070℃ unchanged, form a temperature gradient from top to bottom, control the axial temperature difference at 10-15℃ / cm, induce the melt to start solidifying from the bottom of the crucible; Weak magnetic field application: during the growth process, an axial weak direct current magnetic field is applied to the melt area, the magnetic field strength is controlled at 0.1-0.2T, the natural convection of the melt is suppressed by the Lorentz force, and the solid-liquid interface is stabilized; Interface monitoring: the solid-liquid interface temperature is monitored in real time by an infrared temperature measuring instrument on the side of the furnace, when the interface temperature deviates from 1070±0.5℃, the lower zone cooling rate is automatically adjusted to ensure that the interface is horizontal; The obtained high uniformity indium phosphide crystal has a dislocation density of ≤10 cm⁻²; the indium and phosphorus atomic ratio deviation is ≤0.1%, the radial resistivity fluctuation is ≤3%; the purity is ≥99.9999%.

2. The high uniformity indium phosphide crystal growth process of claim 1, wherein: The raw materials are melted by stages: First stage: heat up to 500℃ at a rate of 5-8℃ / min, keep for 1.5-2 hours; Second stage: heat up to 800℃ at a rate of 2-3℃ / min, keep for 0.5-1 hour; Third stage: heat up to 1070-1075℃ at a rate of 1-1.5℃ / min, keep for 3-4 hours, ensure that the raw materials are completely melted, and form a uniform melt.

3. The high uniformity indium phosphide crystal growth process of claim 1 or 2, wherein: After the growth is completed, annealing and cooling are performed according to the following process: Annealing treatment: after the crystal is completely solidified, the entire furnace is cooled to 600℃ at a rate of 0.5℃ / h, kept for 24 hours to release the internal thermal stress of the crystal; Cooling demolding: after annealing, cool to room temperature at a rate of 2-3℃ / h, open the quartz sealing tube, take out the crucible and peel off the BN coating, obtain an indium phosphide single crystal ingot.

4. The high uniformity indium phosphide crystal growth process of claim 1 or 2, wherein: Including the following steps: 1) Raw material pretreatment: Raw material composition: indium phosphide polycrystalline material and dopant, the molar ratio of indium phosphide polycrystalline material and dopant is 100:(0.008-0.020); Pre-treatment: The raw material is placed in a vacuum baking oven, baked at a temperature of 200-250℃, a vacuum degree of 1×10⁻ 4 Pa, for 4-6 hours to remove the water and oxygen adsorbed on the surface of the raw material; 2) Preparation of crucible and device: Crucible selection: use high-purity quartz crucible, coat the inner wall with 5-10μm thick boron nitride coating to avoid reaction between the melt and quartz; Device assembly: place the coated crucible into the double-zone heating furnace, the furnace is equipped with an axial temperature control system, and the axial temperature control system is surrounded by a radial weak magnetic field generating device; 3) Loading and vacuum sealing: Loading operation: in the inert gas glove box, load the pretreated raw materials and dopant into the quartz crucible, cover it and put it into the quartz sealing tube; Vacuum sealing: The quartz sealing tube was evacuated to a vacuum degree of ≤5 x 10⁻ 5 Pa, and then the two ends of the sealing tube were fused and sealed by a hydrogen-oxygen flame. 4) Melting by stages: First stage: heat up to 500℃ at a rate of 5-8℃ / min, keep for 1.5-2 hours; Second stage: heat up to 800℃ at a rate of 2-3℃ / min, keep for 0.5-1 hour; Third stage: heat up to 1070-1075℃ at a rate of 1-1.5℃ / min, keep for 3-4 hours, ensure that the raw materials are completely melted, and form a uniform melt; 5) Crystal growth: Gradient temperature control: the temperature of the lower zone of the furnace is decreased at a rate of 0.1-0.3℃ / h, and the temperature of the upper zone is kept at 1070℃, so as to form a temperature gradient from top to bottom, and the axial temperature difference is controlled at 10-15℃ / cm, thereby inducing the melt to solidify from the bottom of the crucible; Weak magnetic field application: during the growth process, an axial weak direct-current magnetic field is applied to the melt area, and the magnetic field strength is controlled at 0.1-0.2T, so as to suppress the natural convection of the melt by Lorentz force and stabilize the solid-liquid interface; Interface monitoring: the solid-liquid interface temperature is monitored in real time by an infrared temperature detector on the side of the furnace, and when the interface temperature deviates from 1070±0.5℃, the temperature decreasing rate of the lower zone is automatically adjusted to ensure that the interface is horizontal; 6) Annealing and cooling: Annealing treatment: after the crystal is completely solidified, the whole furnace is cooled to 600℃ at a rate of 0.5℃ / h, and is kept at this temperature for 24 hours to release the internal thermal stress of the crystal; Cooling and demolding: after annealing, the temperature is decreased to room temperature at a rate of 2-3℃ / h, the quartz sealed tube is opened, the crucible is taken out and the BN coating is peeled off, and an indium phosphide single crystal ingot is obtained.

5. The high uniformity indium phosphide crystal growth process of claim 4, wherein: In step 1), the purity of the indium phosphide polycrystal material is 99.9999%.

6. The high uniformity indium phosphide crystal growth process of claim 4, wherein: The dopant is indium sulfide or zinc with a purity of 99.999%.

7. The high uniformity indium phosphide crystal growth process of claim 4, wherein: In step 2), the purity of the high-purity quartz crucible is 99.999%.

8. The high uniformity indium phosphide crystal growth process of claim 4, wherein: In step 2), the accuracy of the temperature control system is ±0.5℃.

9. The high uniformity indium phosphide crystal growth process of claim 4, wherein: In step 3), the inert gas glove box is filled with high-purity argon gas with a purity of 99.999%.

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