Growth method of indium arsenide single crystal

Abstract

A method for growing an indium arsenide single crystal comprises the following steps: S1, cleaning a quartz crucible; S2, loading: loading an indium arsenide seed crystal, an indium arsenide polycrystal, and a liquid sealant into a PBN crucible, and then loading the PBN crucible into a quartz crucible; S3, filling with hydrogen and welding a pipe: plugging a quartz sealing bubble into the opening of the quartz crucible, and then installing the quartz crucible on a sealing flange, evacuating the air, opening the valve of a hydrogen gas cylinder, and introducing hydrogen into the quartz crucible, and opening a hydrogen-oxygen flame, and then welding the quartz crucible and the quartz sealing bubble at a full 360° angle. Upper welding seal; S4, furnace loading: load the quartz crucible sealed by quartz bubble welding into the VGF furnace; S5, heating and seeding: VGF furnace controls temperature rise and keeps warm for 24 hours after stabilization; S6, single crystal growth: VGF furnace controls temperature using VGF process, reducing heating power from bottom to top to cool down, so that the crystal growth surface grows at 0.5mm / h at the position corresponding to the shoulder of the PBN crucible, and the crystal growth surface grows at 0.8mm / h at the position corresponding to the equal diameter part of the PBN crucible.

Description

Technical Field

[0001] The present disclosure relates to the field of crystal growth, and more specifically to a method for growing an indium arsenide single crystal. Background Art

[0002] InAs / GaSb type II superlattice, with adjustable band structure (0-0.8ev), wide response wavelength range, high quantum efficiency, low Auger recombination rate and small dark current, has become the preferred material for the third generation of infrared focal plane detectors. Using indium arsenide (InAs) as the substrate and applying MOCVD technology has become a new direction worthy of research due to its advantages in cost, yield, production capacity and being closer to equilibrium state.

[0003] The VGF method is used to grow InAs single crystals in a sealed quartz tube. When the raw materials (InAs polycrystals) required for growing single crystals are loaded into a quartz crucible, the surface of the raw materials will inevitably be partially oxidized, and the oxides become the main impurities that affect the growth of single crystals, resulting in a decrease in the single crystal rate, or even no large grains that can be used in the entire ingot. Summary of the invention

[0004] In view of the problems existing in the background technology, an object of the present disclosure is to provide a method for growing an indium arsenide single crystal, which can eliminate the formation of oxides during the growth process of the indium arsenide single crystal.

[0005] Another object of the present disclosure is to provide a method for growing an indium arsenide single crystal, which can improve the single crystal rate.

[0006] Thus, a method for growing an indium arsenide single crystal includes the following steps: S1, cleaning a quartz crucible: scrubbing with alcohol to remove grease, soaking with aqua regia to remove free silicon, cleaning with pure water, and drying the quartz crucible; S2, loading: loading an indium arsenide seed crystal, an indium arsenide polycrystal, and a liquid sealant into a PBN crucible, loading the indium arsenide seed crystal into the nose of the PBN crucible, loading the indium arsenide polycrystal and the liquid sealant into the shoulder and equal diameter portion of the PBN crucible, and then loading the PBN crucible into a quartz crucible having an inner cavity shape that matches the PBN crucible. S3, hydrogen filling and pipe welding: plug the quartz bubble into the opening of the quartz crucible loaded with the PBN crucible, then install the quartz crucible on the sealing flange of the hydrogen filling pipe welding device, evacuate the quartz crucible through the sealing flange to exhaust the air, then close the valve connected to the vacuum pump, open the valve of the hydrogen cylinder, and let the hydrogen in the hydrogen cylinder pass into the quartz crucible through the sealing flange. The pressure transmitter of the hydrogen filling pipe welding device detects the pressure in the quartz crucible. When the pressure reaches 25000Pa, the pressure transmitter and the pneumatic diaphragm valve are interlocked to control the pneumatic diaphragm valve to automatically shut off the supply of hydrogen, open the hydrogen-oxygen flame, and weld and seal the quartz crucible and the quartz bubble at a full 360° angle; S4, furnace loading: load the quartz crucible sealed by welding of the quartz bubble into the VGF furnace and support it on the support; S5, heating and seeding: the VGF furnace controls the temperature rise, the equal-diameter part of the PBN crucible is heated to the homogenization temperature, and the upper and lower ends of the indium arsenide seed crystal are heated to the same temperature. The temperature is measured by the thermocouple, and the lower thermocouple is adjusted to be lower than the melting point of indium arsenide, and the upper thermocouple is adjusted to be higher than the melting point of indium arsenide. After stabilization, the temperature is kept for 24 hours; S6, single crystal growth: VGF furnace temperature control adopts VGF process, and the heating power is reduced from bottom to top to cool down, so that the crystal growth surface grows at 0.5mm / h at the position corresponding to the shoulder of the PBN crucible, and the crystal growth surface grows at 0.8mm / h at the position corresponding to the equal diameter part of the PBN crucible.

[0007] The beneficial effects of the present disclosure are as follows: in the method for growing an indium arsenide single crystal according to the present disclosure, the atmosphere in the quartz crucible is a reducing hydrogen atmosphere by filling hydrogen and welding the pipe in step S3, and the temperature rise in step S5 makes the liquid sealant melt and float on the surface of the melt formed by the indium arsenide polycrystal to achieve liquid sealing, and the reducing hydrogen atmosphere in the quartz crucible makes the original oxygen element in the indium arsenide polycrystal in the PBN crucible in the melting process of the indium arsenide polycrystal in step S6 and the growth of the single crystal be removed by reacting with hydrogen, eliminating the oxides formed in the charging process of step S2, and then the oxides become the main impurities affecting the growth of the single crystal, causing heterogeneous nucleation, thereby improving the single crystal rate. As verified by the test, the entire crystal rod can be obtained as a full single crystal. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram of hydrogen filling and welding pipe of a hydrogen filling welding pipe device in the method for growing an indium arsenide single crystal according to the present disclosure.

[0009] Figure 2 It is a schematic diagram of loading a quartz crucible sealed by quartz bubble welding into a VGF furnace in the method for growing an indium arsenide single crystal according to the present disclosure.

[0010] Figure 3 This is a photograph of the indium arsenide single crystal grown in Example 1.

[0011] Figure 4 This is a photograph of the indium arsenide single crystal grown in Example 2.

[0012] The description of the accompanying drawings is as follows.

[0013] 1 Quartz Crucible 400e Pressure Reducing Valve

[0014] 2PBN crucible 400f float flowmeter

[0015] 21 Nose 400g one-way valve

[0016] 22 Shoulder 400h flame arrester

[0017] 23 equal diameter 400i braided tube

[0018] 3 quartz bubble 400j air release valve

[0019] 100 InAs Seed Crystal 500VGF Furnace

[0020] 200 InAs polycrystalline 500a support

[0021] 300 liquid sealant 500b lower end of the thermal couple

[0022] 400 Hydrogen gas welding pipe device 500c upper end of the thermocouple

[0023] 400a sealing flange 500d thermal couple on the shoulder

[0024] 400b hydrogen cylinder 500f temperature zone

[0025] 400c pressure transmitter 500g heater

[0026] 400d pneumatic diaphragm valve 500i temperature zone thermocouple DETAILED DESCRIPTION

[0027] The accompanying drawings show embodiments of the present disclosure, and it will be understood that the disclosed embodiments are merely examples of the present disclosure, and the present disclosure can be implemented in various forms. Therefore, the specific details disclosed herein should not be interpreted as limiting, but merely as the basis for the claims and as a representative basis for teaching ordinary technicians in the field to implement the present disclosure in various ways.

[0028] [Method for growing indium arsenide single crystal]

[0029] Reference Figure 1 and Figure 2 According to the present disclosure, the method for growing an indium arsenide single crystal comprises the following steps:

[0030] S1, cleaning the quartz crucible 1: scrubbing with alcohol to remove grease, soaking with aqua regia to remove free silicon, cleaning with pure water, and drying the quartz crucible 1;

[0031] S2, loading: loading the indium arsenide seed crystal 100, the indium arsenide polycrystal 200, and the liquid sealing agent 300 into the PBN crucible 2, loading the indium arsenide seed crystal 100 into the nose 21 of the PBN crucible 2, loading the indium arsenide polycrystal 200 and the liquid sealing agent 300 into the shoulder 22 and the equal diameter part 23 of the PBN crucible 2, and then loading the PBN crucible 2 into the quartz crucible 1 whose inner cavity shape is complementary to that of the PBN crucible 2;

[0032] S3, hydrogen filling and pipe welding: plug the quartz sealing bubble 3 into the opening of the quartz crucible 1 loaded with the PBN crucible 2, then install the quartz crucible 1 on the sealing flange 400a of the hydrogen filling pipe welding device 400, evacuate the quartz crucible 1 through the sealing flange 400a to exhaust the air, then close the valve connected to the vacuum pump, open the valve of the hydrogen gas cylinder 400b, and the hydrogen in the hydrogen gas cylinder 400b is passed into the quartz crucible 1 through the sealing flange 400a. When the pressure transmitter 400c of the hydrogen filling pipe welding device 400 detects that the pressure in the quartz crucible 1 reaches 25000Pa, the pressure transmitter 400c and the pneumatic diaphragm valve 400d are interlocked to control the pneumatic diaphragm valve 400d to automatically shut off the supply of hydrogen, open the hydrogen-oxygen flame, and weld and seal the quartz crucible 1 and the quartz sealing bubble 3 over a full circumference of 360°;

[0033] S4, furnace loading: the quartz crucible 1 sealed by welding of the quartz bubble 3 is loaded into the VGF furnace 500 and supported on the support 500a;

[0034] S5, heating and seeding: the VGF furnace 500 controls the temperature rise, the equal diameter part 23 of the PBN crucible 2 is heated to the homogenization temperature, and the thermocouples at the upper and lower ends of the InAs seed crystal 100 are used as the reference, the thermocouple 500b at the lower end is adjusted to be lower than the melting point temperature of InAs, and the thermocouple 500c at the upper end is adjusted to be higher than the melting point temperature of InAs, and the temperature is kept for 24 hours after stabilization;

[0035] S6, single crystal growth: The VGF furnace 500 controls the temperature by adopting the VGF process, reducing the heating power from bottom to top to cool down, so that the crystal growth surface grows at 0.5 mm / h at the position corresponding to the shoulder 22 of the PBN crucible 2, and the crystal growth surface grows at 0.8 mm / h at the position corresponding to the equal diameter portion 23 of the PBN crucible 2.

[0036] In the indium arsenide single crystal growth method disclosed in the present invention, the atmosphere in the quartz crucible 1 is a reducing hydrogen atmosphere by filling hydrogen and welding the pipe in step S3, and the temperature rise in step S5 makes the liquid sealant float on the surface of the melt formed by the indium arsenide polycrystal 200 after melting to achieve liquid sealing. The reducing hydrogen atmosphere in the quartz crucible 1 makes the original oxygen element in the indium arsenide polycrystal 200 in the PBN crucible 2 during the melting process of the indium arsenide polycrystal 200 in step S6 and the growth of the single crystal be removed by reacting with hydrogen, eliminating the oxides formed in the charging process in step S2, thereby preventing the oxides from becoming the main impurities affecting the growth of the single crystal and causing heterogeneous nucleation, thereby improving the single crystal rate. As verified by the subsequent test, the entire crystal rod can be obtained as a full single crystal.

[0037] In step S1, for example, the sample is immersed in aqua regia for 12 hours.

[0038] In step S2, the liquid sealing agent 300 is, for example, boron oxide. Specifically, in step S2, the process of loading the indium arsenide seed crystal 100, the indium arsenide polycrystal 200, and the liquid sealing agent 300 into the PBN crucible 2 is as follows: firstly, the indium arsenide seed crystal 100 is loaded into the nose 21 of the PBN crucible 2, then, a part of the indium arsenide polycrystal 200 is loaded, then, the liquid sealing agent 300 is loaded, and finally, the remaining part of the indium arsenide polycrystal 200 is loaded.

[0039] In step S3, for example, the purity of hydrogen is 9N.

[0040] In step S4 , for example, the difference in the gap between the quartz crucible 1 and the surroundings of the support member 500 a of the VGF furnace 500 is less than 2 mm.

[0041] In step S5, in one example, the equal diameter portion 23 of the PBN crucible 2 is heated to a homogenizing temperature of 970°C, the thermocouple 500b at the lower end of the InAs seed crystal 100 is 925°C, and the thermocouple 500c at the upper end of the InAs seed crystal 100 is 955°C.

[0042] In one example, the performance of the single crystal grown in step S6 meets the IQE (Internal Quantum Efficiency) standard: the carrier concentration is (1-3)E16cm -3 , mobility ≥ 20000cm 2 V -1 s -1 , EPD<50000. Specifically, the carrier concentration is (2.17-2.2)E16cm -3 , the mobility is 28040-29900cm 2 V -1 s -1 , EPD (Etch pits Density) is 248-4500.

[0043] In one example, the diameter of the crystal rod grown in step S6 is 2 inches or 4 inches, and the entire crystal rod is a single crystal.

[0044] In addition, if Figure 1 As shown, the hydrogen-filled welding pipe device further includes a pressure reducing valve 400e, a float flowmeter 400f, a one-way valve 400g, a flame arrester 400h, a braided tube 400i and a vent valve 400j.

[0045] In addition, if Figure 2 As shown, the VGF furnace 500 includes a plurality of temperature zones 500f, a plurality of heating zones 500g, a plurality of temperature zone thermocouples 500i and a thermocouple 500d at a shoulder. The heating power of the plurality of heating zones 500g at the plurality of temperature zones 500f is controlled and the corresponding temperatures are monitored by the thermocouple 500b at the lower end of the indium arsenide seed crystal 100, the thermocouple 500c at the upper end of the indium arsenide seed crystal 100, the thermocouple 500d at the shoulder and the plurality of temperature zone thermocouples 500i, so that the temperature of the aforementioned VGF furnace 500 is controlled by adopting the VGF process.

[0046] [test]

[0047] Example 1

[0048] Reference Figure 1 and Figure 2 The method for growing an indium arsenide single crystal in Example 1 adopts the following steps:

[0049] S1, cleaning the quartz crucible 1: scrub with alcohol to remove grease, soak in aqua regia for 12 hours to remove free silicon, clean with pure water, and dry the quartz crucible 1;

[0050] S2, charging: 100 indium arsenide seed crystals, 1.6 kg indium arsenide polycrystals 200, and 18 g boron oxide liquid sealing agent 300 are charged into the PBN crucible 2, firstly the indium arsenide seed crystals 100 are charged into the nose 21 of the PBN crucible 2, then a part of the indium arsenide polycrystals 200 are charged, then the liquid sealing agent 300 is charged, and finally the remaining part of the indium arsenide polycrystals 200 are charged, the indium arsenide polycrystals 200 and the liquid sealing agent 300 are charged into the shoulder 22 and the equal diameter part 23 of the PBN crucible 2, then the PBN crucible 2 is charged into the quartz crucible 1 whose inner cavity shape is complementary to that of the PBN crucible 2, and the inner diameter of the equal diameter part of the PBN crucible 2 is 2 inches;

[0051] S3, hydrogen filling and pipe welding: plug the quartz sealing bubble 3 into the opening of the quartz crucible 1 loaded with the PBN crucible 2, then install the quartz crucible 1 on the sealing flange 400a of the hydrogen filling pipe welding device 400, evacuate the quartz crucible 1 through the sealing flange 400a to exhaust the air, then close the valve connected to the vacuum pump, open the valve of the hydrogen cylinder 400b, and the hydrogen with a purity of 9N in the hydrogen cylinder 400b is passed into the quartz crucible 1 through the sealing flange 400a. When the pressure transmitter 400c of the hydrogen filling pipe welding device 400 detects that the pressure in the quartz crucible 1 reaches 25000Pa, the pressure transmitter 400c and the pneumatic diaphragm valve 400d are interlocked to control the pneumatic diaphragm valve 400d to automatically shut off the supply of hydrogen, open the hydrogen-oxygen flame, and weld and seal the quartz crucible 1 and the quartz sealing bubble 3 over a full circumference of 360°;

[0052] S4, furnace loading: the quartz crucible 1 sealed by welding of the quartz bubble 3 is loaded into the VGF furnace 500, supported on the support 500a, and the difference in the gap between the quartz crucible 1 and the support 500a of the VGF furnace 500 is less than 2 mm;

[0053] S5, heating and seeding: the VGF furnace 500 controls the temperature rise, the equal diameter part 23 of the PBN crucible 2 is heated to a homogenization temperature of 970°C, and the thermocouples measuring the temperature at the upper and lower ends of the indium arsenide seed crystal 100 are used as the reference, the thermocouple 500b at the lower end is adjusted to 925°C, which is lower than the melting point of indium arsenide, and the thermocouple 500c at the upper end is adjusted to 955°C, which is higher than the melting point of indium arsenide, and then kept warm for 24 hours after stabilization;

[0054] S6, single crystal growth: The VGF furnace 500 controls the temperature by adopting the VGF process, reducing the heating power from bottom to top to cool down, so that the crystal growth surface grows at 0.5 mm / h at the position corresponding to the shoulder 22 of the PBN crucible 2, and the crystal growth surface grows at 0.8 mm / h at the position corresponding to the equal diameter portion 23 of the PBN crucible 2.

[0055] Example 2

[0056] Except that in step S2, the indium arsenide polycrystal 200 is 6 kg, the boron oxide is 36 g, and the inner diameter of the equal diameter part of the PBN crucible 2 is 4 inches, the rest is the same as in Example 1.

[0057] Figure 3 This is a photograph of the indium arsenide single crystal (i.e., crystal rod) grown in Example 1. Figure 4 is a photograph of the indium arsenide single crystal (i.e., crystal rod) grown in Example 2. Figure 3 and Figure 4 It can be seen that there are no twin lines or polycrystalline lines on the surface of the entire crystal rod, which indicates that the entire crystal rod is a single crystal.

[0058] Table 1 shows the diameter of the equal-diameter section (i.e., the portion corresponding to the equal-diameter portion 2 of the PBN crucible 2) of the grown InAs single crystal (i.e., the crystal rod) of Examples 1-2, and the carrier concentration, mobility, and dislocation EPD test results of the slices made at the tail of the equal-diameter section of the crystal rod adjacent to the shoulder section (i.e., the portion corresponding to the shoulder portion 22 of the PBN crucible 2).

[0059] Table 1 Test results of the grown indium arsenide single crystals of Examples 1-2

[0060]

[0061] The above detailed description is used to describe multiple exemplary embodiments, but this document is not intended to be limited to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined together to form multiple additional combinations that are not shown for the sake of simplicity.

Claims

1. A method for growing an indium arsenide single crystal, characterized in that: Includes steps: S1, cleaning the quartz crucible (1): scrubbing with alcohol to remove grease, soaking with aqua regia to remove free silicon, cleaning with pure water, and drying the quartz crucible (1); S2, loading: loading indium arsenide seed crystal (100), indium arsenide polycrystal (200), and liquid sealing agent (300) into a PBN crucible (2), loading the indium arsenide seed crystal (100) into the nose (21) of the PBN crucible (2), loading the indium arsenide polycrystal (200) and liquid sealing agent (300) into the shoulder (22) and equal diameter portion (23) of the PBN crucible (2), and then loading the PBN crucible (2) into a quartz crucible (1) whose inner cavity shape is complementary to that of the PBN crucible (2); S3, hydrogen filling and pipe welding: plug the quartz sealing bubble (3) into the opening of the quartz crucible (1) loaded with the PBN crucible (2), then install the quartz crucible (1) on the sealing flange (400a) of the hydrogen filling pipe welding device (400), evacuate the quartz crucible (1) through the sealing flange (400a) to exhaust the air, then close the valve connected to the vacuum pump, open the valve of the hydrogen gas cylinder (400b), and the hydrogen in the hydrogen gas cylinder (400b) is discharged. The hydrogen gas is introduced into the quartz crucible (1) through the sealing flange (400a). When the pressure transmitter (400c) of the hydrogen gas welding pipe device (400) detects that the pressure in the quartz crucible (1) reaches 25000 Pa, the pressure transmitter (400c) and the pneumatic diaphragm valve (400d) are interlocked to control the pneumatic diaphragm valve (400d) to automatically shut off the supply of hydrogen gas, open the hydrogen-oxygen flame, and weld the quartz crucible (1) and the quartz sealing bubble (3) to seal over a full 360° circumference; S4, furnace loading: loading the quartz crucible (1) sealed by welding of the quartz bubble (3) into the VGF furnace (500), and supporting it on the support (500a); S5, heating and seeding: the VGF furnace (500) controls the temperature rise, the equal diameter part (23) of the PBN crucible (2) is heated to the homogenization temperature, and the thermocouples for measuring the temperature at the upper and lower ends of the indium arsenide seed crystal (100) are used as the reference, and the thermocouple (500b) at the lower end is adjusted to be lower than the melting point temperature of indium arsenide, and the thermocouple (500c) at the upper end is adjusted to be higher than the melting point temperature of indium arsenide, and the temperature is kept for 24 hours after stabilization; S6, single crystal growth: the VGF furnace (500) controls the temperature by adopting the VGF process, and reduces the heating power from bottom to top to lower the temperature, so that the crystal growth surface grows at 0.5 mm / h at a position corresponding to the shoulder portion (22) of the PBN crucible (2), and the crystal growth surface grows at 0.8 mm / h at a position corresponding to the equal diameter portion (23) of the PBN crucible (2).

2. The method for growing an indium arsenide single crystal according to claim 1, characterized in that: In step S1, soak in aqua regia for 12 hours.

3. The method for growing an indium arsenide single crystal according to claim 1, characterized in that: In step S2, the liquid sealing agent (300) is boron oxide. In step S2, the process of loading the indium arsenide seed crystal (100), the indium arsenide polycrystal (200), and the liquid sealing agent (300) into the PBN crucible (2) is as follows: firstly, the indium arsenide seed crystal (100) is loaded into the nose (21) of the PBN crucible (2), then a part of the indium arsenide polycrystal (200) is loaded, then the liquid sealing agent (300) is loaded, and finally the remaining part of the indium arsenide polycrystal (200) is loaded.

4. The method for growing an indium arsenide single crystal according to claim 1, characterized in that: In step S3, the purity of hydrogen is 9N.

5. The method for growing an indium arsenide single crystal according to claim 1, characterized in that: In step S4, the difference in the gap between the quartz crucible (1) and the surroundings of the support (500a) of the VGF furnace (500) is less than 2 mm.

6. The method for growing an indium arsenide single crystal according to claim 1, characterized in that: In step S5, The equal diameter portion (23) of the PBN crucible (2) is heated to a homogenization temperature of 970°C. The temperature of the thermocouple (500b) at the lower end of the indium arsenide seed crystal (100) is 925°C, and the temperature of the thermocouple (500c) at the upper end of the indium arsenide seed crystal (100) is 955°C.

7. The method for growing an indium arsenide single crystal according to claim 1, characterized in that: The performance of the single crystal grown in step S6 meets the IQE standard: the carrier concentration is (1-3)E16cm -3 , mobility ≥ 20000cm 2 V -1 s -1 , EPD <50000.

8. The method for growing an indium arsenide single crystal according to claim 7, characterized in that: The diameter of the crystal rod that can be grown in step S6 is 2 inches or 4 inches, and the entire crystal rod is a single crystal.

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