Method of annealing indium antimonide wafer

Abstract

An annealing method of an indium antimonide wafer includes the steps of: S1, growing an undoped Te InSb crystal by a pulling method, the carrier concentration of the InSb crystal being 2E14 / cm 3 The following InSb crystal; S2, slicing the InSb crystal as an InSb wafer; S3, grinding and polishing the InSb wafer; S4, adding a mixed solution of ethanol and tellurium tetrachloride into a flask through a grinding mouth of the flask, the mass fraction of the tellurium tetrachloride in the mixed solution being 1-5%, and the other grinding mouth of the flask being used for installing a recondensation device; S5, putting the ground and polished InSb wafer into the mixed solution in the flask through the grinding mouth and completely immersing the InSb wafer in the mixed solution; S6, installing the recondensation device on the corresponding grinding mouth of the flask and plugging the other grinding mouth of the flask; S7, heating the mixed solution in the flask to 60-70 DEG C and annealing for 10-20 hours in a recondensation mode, and completing the annealing. Thus, the doping uniformity of the indium antimonide wafer is improved, and the problem of uneven stripes of the manufactured InSb detector is fundamentally solved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of indium antimonide crystals, and more particularly to an annealing method of an indium antimonide wafer. BACKGROUND

[0002] Indium antimonide (InSb) is a narrow bandgap III-V semiconductor material with a bandgap of 0.232 eV at 77 K, and it is intrinsically absorbed in the 3-5 μm waveband. It has extremely high electron mobility and is currently one of the best materials for mid-wave infrared detectors. The melting point of indium antimonide is 525℃, and compared with other III-V compounds, it is easy to purify and grow single crystals, so it is often chosen as the object of solid-state theoretical research of III-V compounds.

[0003] N-type indium antimonide crystals generally need to be doped with Te elements. However, because the Te element has a segregation coefficient <1, the concentration of Te elements in the crystal increases with the growth of the crystal. Moreover, due to the existence of facet effect, the amount of Te element doped in the small plane region and the non-small plane region is different, resulting in non-uniformity of the electrical parameters of the crystal in the radial direction. In view of the problem of axial doping non-uniformity, the growth rate and rotation speed of the crystal throughout the growth process are adjusted in “Research Progress of Indium Antimonide Single Crystal Materials” (Zhe Weilin et al., Laser and Infrared, Vol. 54, No. 2, February 2024, pp. 235-241) to reduce the Te element non-uniformity in the axial direction of the crystal, thereby improving the electrical parameter uniformity in the axial direction of the crystal. In view of the problem of radial doping non-uniformity, the solid-liquid interface of the crystal is stably controlled to control the size of the small plane region as much as possible, thereby improving the electrical parameter uniformity in the radial direction of the crystal. However, despite this, vertical non-uniformity stripes can still be seen in the signal response diagram of the InSb detector, and the existence of these stripes indicates that there is still a large non-uniformity in the wafer, which seriously affects the use effect of the detector prepared from the material.

[0004] Annealing is a commonly used method to improve the electrical uniformity of materials. In the commonly used gas phase annealing / vacuum annealing process, Te atoms in InSb migrate in the crystal by diffusion at high temperature, but InSb also decomposes at high temperature, causing damage to the surface of the wafer, and easily generating thermal stress, causing dislocation proliferation. Moreover, in order to ensure a low enough oxygen content, a larger vacuum chamber is needed to control the defects of the single crystal when using gas as the annealing medium, which increases the equipment cost and process complexity.

[0005] Therefore, it is necessary to further improve the doping uniformity of indium antimonide wafers to ensure the use effect of the InSb detector prepared therefrom. SUMMARY

[0006] In view of the problems in the background art, an object of the present disclosure is to provide an annealing method for an indium antimonide wafer, which can improve the doping uniformity of the indium antimonide wafer.

[0007] Another object of the present disclosure is to provide an annealing method for an indium antimonide wafer, which can fundamentally solve the problem of uneven stripes of an InSb detector made of the indium antimonide wafer, thereby ensuring the use effect of the InSb detector made of the indium antimonide wafer.

[0008] Still another object of the present disclosure is to provide an annealing method for an indium antimonide wafer, which can reduce the damage to the InSb wafer.

[0009] Yet another object of the present disclosure is to provide an annealing method for an indium antimonide wafer, which requires simple equipment.

[0010] Thus, an annealing method for an indium antimonide wafer includes the steps of: S1, growing an InSb crystal by a pulling method, the carrier concentration of the InSb crystal being 2E14 / cm 3 The following InSb crystal; S2, slicing the InSb crystal as an InSb wafer; S3, polishing the InSb wafer; S4, adding a mixed solution of ethanol and tellurium tetrachloride into a flask through a grinding mouth of the flask, the mass fraction of the tellurium tetrachloride in the mixed solution being 1-5%, and the other grinding mouth of the flask being used to install a recondensation device; S5, putting the polished InSb wafer into the mixed solution in the flask through the grinding mouth and completely immersing the InSb wafer in the mixed solution; S6, installing the recondensation device on the corresponding grinding mouth of the flask and plugging the other grinding mouth of the flask; S7, heating the mixed solution in the flask to 60-70°C and annealing for 10-20h in a recondensation mode, and completing the annealing.

[0011] The present disclosure has the following beneficial effects.

[0012] In the annealing method for an indium antimonide wafer according to the present disclosure, the InSb crystal is grown by the pulling method in step S1, the carrier concentration of the InSb crystal being 2E14 / cm 3 The following InSb crystal; after the InSb wafer is made in steps S2 to S3, the recondensation mode liquid phase annealing is performed in the mixed solution composed of ethanol and tellurium tetrachloride in steps S4 to S7, the Te in the mixed solution gradually diffuses into the InSb wafer, the purpose of uniform doping is achieved, that is, the doping uniformity of the indium antimonide wafer is improved, and the problem of uneven stripes of an InSb detector made of the indium antimonide wafer is fundamentally solved, thereby ensuring the use effect of the InSb detector made of the indium antimonide wafer.

[0013] Compared with the doping mode in the pull-up method for growing InSb crystals in the background art, in the annealing method for InSb wafer according to the present disclosure, the doping of Te is adjusted to the annealing process through steps S1 to S7, that is, the annealing process has the dual functions of doping and annealing, so that the uniformity of Te doping is more convenient and effective.

[0014] In the annealing method for InSb wafer according to the present disclosure, in steps S4 to S7, the use of the condensation device avoids the loss of Te caused by the volatilization of ethanol, and ensures the accuracy of doping.

[0015] In the annealing method for InSb wafer according to the present disclosure, through steps S4 to S7, the carrier concentration of the InSb wafer after annealing can be in the range of 4E14 / cm 3 -1.4E15 / cm 3 , which ensures the use effect of the InSb detector made of the InSb wafer.

[0016] In the annealing method for InSb wafer according to the present disclosure, using the mixed solution in liquid phase as the annealing medium makes the defect reaction process (that is, the redistribution of doping and the existing impurities inside) more moderate, reduces the damage to the InSb wafer, and the required equipment is relatively simple. Because the mixed solution in liquid phase has no definite shape and good fluidity, the liquid phase annealing is not limited by the size of the InSb wafer, as long as it can flow and cover the InSb wafer. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic diagram of an exemplary pull-up method growth device involved in the annealing method for InSb wafer according to the present disclosure.

[0018] Figure 2 is a schematic diagram of an exemplary flask with a condensation device involved in the annealing method for InSb wafer according to the present disclosure.

[0019] Figure 3 is a carrier concentration distribution diagram of a slice at the head of the InSb crystal rod after the pull-up method growth of Example 1.

[0020] Figure 4 is a carrier concentration distribution diagram of a slice at the tail of the InSb crystal rod after the pull-up method growth of Example 1.

[0021] Figure 5 is a carrier concentration distribution diagram of the InSb wafer after annealing of Example 1.

[0022] Figure 6 is an InSb detector signal response diagram of the InSb wafer after annealing of Example 1 after making an InSb infrared focal plane detector.

[0023] Figure 7 This is a diagram showing the carrier concentration distribution of the InSb wafer in Comparative Example 1 after annealing.

[0024] Figure 8 This is a diagram showing the carrier concentration distribution of the InSb wafer in Comparative Example 2 after annealing.

[0025] Figure 9 This is a diagram showing the carrier concentration distribution of the InSb wafer in Comparative Example 3 after annealing.

[0026] Figure 10 This is a carrier concentration distribution diagram of the InSb wafer fabricated from the InSb ingot grown by the Czochralski method in Comparative Example 4.

[0027] Figure 11 This is a diagram showing the InSb detector signal response of the InSb wafer used in Comparative Example 4 after it was used to fabricate an InSb infrared focal plane detector. Detailed Implementation

[0028] It will be understood that the disclosed embodiments are merely examples of this disclosure, which can be implemented in various forms. Therefore, the specific details disclosed herein should not be construed as limiting, but are intended only as the basis for the claims and as an illustrative basis to teach those skilled in the art how to implement this disclosure in various ways.

[0029] Annealing method for indium antimonide wafers

[0030] Reference Figure 1 and Figure 2 The annealing method for indium antimonide wafers according to this disclosure includes the following steps:

[0031] S1, undoped Te was grown using the Czochralski method with a carrier concentration of 2E14 / cm². 3 The following InSb crystals;

[0032] S2, slice the InSb crystal as an InSb wafer;

[0033] S3, grinding and polishing the InSb wafer;

[0034] S4. Add a mixed solution of ethanol and tellurium tetrachloride to the flask through one ground joint. The mass fraction of tellurium tetrachloride in the mixed solution is 1-5%. The other ground joint of the flask is used to install the condensation device.

[0035] S5, the polished InSb wafer is placed into the mixed solution in the flask through one of the ground joints and completely immersed in the mixed solution;

[0036] S6, Install the condensation re-condensation device on the corresponding ground joint of the flask, and seal the other ground joint of the flask;

[0037] S7. Heat the mixed solution in the flask to 60-70℃ and anneal it for 10-20 hours using the re-condensation method to complete the annealing.

[0038] In the annealing method for indium antimonide wafers according to this disclosure, undoped Te carriers with a concentration of 2E14 / cm² are grown by Czochralski method in step S1. 3 The InSb crystals described below, after the InSb wafers are fabricated in steps S2 to S3, undergo liquid-phase annealing via re-condensation in a mixed solution of ethanol and tellurium tetrachloride in steps S4 to S7. The Te in the mixed solution gradually diffuses into the InSb wafer, achieving uniform doping. This improves the doping uniformity of the indium antimonide wafer, fundamentally solving the problem of uneven stripes in the InSb detector fabricated from the indium antimonide wafer, thus ensuring the performance of the InSb detector fabricated from the indium antimonide wafer.

[0039] Compared with the doping method of InSb crystal growth by the Czochralski method in the prior art, in the annealing method of indium antimonide wafer according to the present disclosure, the doping of Te is adjusted to the annealing process through steps S1 to S7. That is, the annealing process has the dual functions of doping and annealing, making the uniformity of Te doping simpler and more effective.

[0040] In the annealing method for indium antimonide wafers according to this disclosure, the use of a re-condensation device in steps S4 to S7 avoids the loss of Te due to ethanol evaporation and ensures the accuracy of doping.

[0041] In the annealing method for indium antimonide wafers according to this disclosure, steps S4 to S7 enable the carrier concentration of the annealed InSb wafer to be at 4E14 / cm². 3 -1.4E15 / cm 3 Within a certain range, the performance of the InSb detector made from indium antimonide wafers is guaranteed.

[0042] In the annealing method for indium antimonide wafers according to this disclosure, using a liquid-phase mixed solution as the annealing medium makes the defect reaction process (i.e., doping and redistribution of existing impurities) more moderate, reduces damage to the InSb wafer, and requires relatively simple equipment. Because the liquid-phase mixed solution has no definite shape and good fluidity, liquid-phase annealing is not limited by the size of the InSb wafer, as long as it can flow and cover the InSb wafer.

[0043] In one example, refer to Figure 1 In step S1, the lifting method employs the following sub-steps:

[0044] S11, the 7.5N InSb polycrystalline material purified by zone melting is cleaned with aqua regia and then subjected to a process called deionization.

[0045] Rinse with water at least 3 times, then dry in a vacuum oven for later use;

[0046] S12, put the dried and ready-to-use InSb polycrystalline material into the quartz crucible;

[0047] S13. Evacuate, purge, and leak-check the Czochralski crystal growth equipment to achieve a vacuum pressure below 10 Pa (monitored by a pressure gauge (not shown)). Evacuation and purge are performed alternately 2-3 times using a vacuum pump and nitrogen filling. The vacuum port is located at the bottom of the Czochralski crystal growth equipment. Nitrogen (7N purity) is used for purge.

[0048] The gas inlet is located at the top of the Czochralski crystal growth equipment;

[0049] S14. After sub-step S13 is completed, the top cover and the middle cylinder are locked with corresponding screws, and the middle cylinder and the base are locked with corresponding screws. After that, the vacuum port and the gas inlet are closed.

[0050] S15, reopen the gas inlet and fill the Czochralski crystal growth equipment with a nitrogen-hydrogen mixture to bring the pressure inside the equipment to 0.1 MPa (monitored by a pressure gauge), then close the gas inlet.

[0051] S16, heating of the quartz crucible is initiated to melt the InSb polycrystalline material inside. The heater comprises a graphite heater, a double-layer graphite insulation cover, and carbon felt. The graphite heater surrounds the crucible, and the double-layer graphite insulation cover surrounds the graphite heater. The carbon felt fills the space between the inner and outer layers of the double-layer graphite insulation cover. The heater for heating the quartz crucible is a Czochralski crystal growth device.

[0052] The only heating device in the long equipment;

[0053] S17, when the pressure inside the Czochralski crystal growth apparatus after the InSb polycrystalline material has completely melted and formed a melt reaches 0.15 MPa (monitored by a pressure gauge), the temperature of the quartz crucible is kept constant.

[0054] The formation of the melt is confirmed by observation through an observation window (not shown, located on the top cover);

[0055] In step S18, following sub-step S17, the pulling rod drives the seed crystal downwards into the quartz crucible, immersing it from the melt surface. The pulling rod then pulls the crystal upwards to grow a crystal rod. During crystal growth, the quartz crucible and the pulling rod maintain opposite rotational speeds: the crucible rotates at 1 rpm, and the pulling rod rotates at 3 rpm. The seed crystal is a 7.5N purity indium antimonide single crystal, and the pulling speed is constant.

[0056] Set at 5mm / h;

[0057] S19. After crystal growth is completed, stop heating, cool down, and replace the gas in the Czochralski crystal growth equipment with nitrogen again through the vacuum pump via the vacuum port and gas inlet. Then, turn on the Czochralski crystal growth equipment and cut the crystal rod off the pulling rod.

[0058] Note that before the vacuum pump is turned on in sub-steps S15 to S19, the atmosphere inside the Czochralski crystal growth apparatus is a closed nitrogen-hydrogen mixture.

[0059] In one example, in step S2, the InSb crystal is sliced ​​using diamond single-wire cutting.

[0060] In one example, in step S3, a double-sided grinding machine is used for grinding and polishing.

[0061] In one example, in step S3, the grinding and polishing process uses a polishing solution prepared by mixing SiO2 sol and pure water at a volume ratio of 1:1 at room temperature, and the grinding and polishing time is 30 seconds.

[0062] In one example, in step S4, the ethanol is 99% ethanol by mass.

[0063] In step S5, the inner diameter of the corresponding ground joint for placing the InSb wafer is sufficient to accommodate the InSb wafer.

[0064] In one example, in step S7, the temperature is increased using a water bath. Specifically, as shown... Figure 2 As shown, the flask is placed in a water bath, and the water in the water bath is heated using a heating device to achieve water bath temperature rise. The heating device can be an electric heating device.

[0065] In one example, in step S7, the re-condensation method involves the re-condensation device installed at the corresponding ground joint being connected to circulating cooling water through two ports to achieve the re-condensation of the mixed solution volatilized during the heating process and its return to the mixed solution.

[0066] [test]

[0067] Example 1

[0068] Example 1 uses the following steps:

[0069] S1, undoped Te was grown using the Czochralski method with a carrier concentration of 2E14 / cm². 3 The following InSb crystals are produced using the Czochralski method with the following sub-steps:

[0070] S11, the 7.5N InSb polycrystalline material purified by zone melting is cleaned with aqua regia and then subjected to a process called deionization.

[0071] Rinse with water at least 3 times, then dry in a vacuum oven for later use;

[0072] S12, put the dried and ready-to-use InSb polycrystalline material into the quartz crucible;

[0073] S13. Evacuate, purge, and leak-check the Czochralski crystal growth equipment to achieve a vacuum pressure below 10 Pa (monitored by a pressure gauge (not shown)). Evacuation and purge are performed alternately 2-3 times using a vacuum pump and nitrogen filling. The vacuum port is located at the bottom of the Czochralski crystal growth equipment. Nitrogen (7N purity) is used for purge.

[0074] The gas inlet is located at the top of the Czochralski crystal growth equipment;

[0075] S14. After sub-step S13 is completed, the top cover and the middle cylinder are locked with corresponding screws, and the middle cylinder and the base are locked with corresponding screws. After that, the vacuum port and the gas inlet are closed.

[0076] S15, reopen the gas inlet and fill the Czochralski crystal growth equipment with a nitrogen-hydrogen mixture to bring the pressure inside the equipment to 0.1 MPa (monitored by a pressure gauge), then close the gas inlet.

[0077] S16, heating of the quartz crucible is initiated to melt the InSb polycrystalline material inside. The heater comprises a graphite heater, a double-layer graphite insulation cover, and carbon felt. The graphite heater surrounds the crucible, and the double-layer graphite insulation cover surrounds the graphite heater. The carbon felt fills the space between the inner and outer layers of the double-layer graphite insulation cover. The heater for heating the quartz crucible is a Czochralski crystal growth device.

[0078] The only heating device in the long equipment;

[0079] S17, when the pressure inside the Czochralski crystal growth apparatus after the InSb polycrystalline material has completely melted and formed a melt reaches 0.15 MPa (monitored by a pressure gauge), the temperature of the quartz crucible is kept constant.

[0080] The formation of the melt is confirmed by observation through an observation window (not shown, located on the top cover);

[0081] In step S18, following sub-step S17, the pulling rod drives the seed crystal downwards into the quartz crucible, immersing it from the melt surface. The pulling rod then pulls the crystal upwards to grow a crystal rod. During crystal growth, the quartz crucible and the pulling rod maintain opposite rotational speeds: the crucible rotates at 1 rpm, and the pulling rod rotates at 3 rpm. The seed crystal is a 7.5N purity indium antimonide single crystal, and the pulling speed is constant.

[0082] Set at 5mm / h;

[0083] S19, after crystal growth is complete, stop heating, cool down, and then replace the gas in the Czochralski crystal growth equipment with nitrogen again through the vacuum pump via the vacuum port and gas inlet.

[0084] The Czochralski crystal growth equipment cuts the crystal rod from the pulling rod;

[0085] S2, InSb crystal slices are cut into InSb wafers using diamond single-wire cutting;

[0086] S3, the InSb wafer is polished using a double-sided grinder. The polishing solution is prepared by mixing SiO2 sol and pure water at a volume ratio of 1:1 at room temperature, and the polishing time is 30 seconds.

[0087] S4. Add a mixed solution of ethanol and tellurium tetrachloride to the flask through one ground joint. The ethanol is 99% by mass, and the tellurium tetrachloride has a mass fraction of 3% in the mixed solution. The other ground joint of the flask is used to install the condensation device.

[0088] S5, the polished InSb wafer is placed into the mixed solution in the flask through one of the ground joints and completely immersed in the mixed solution;

[0089] S6, Install the condensation re-condensation device on the corresponding ground joint of the flask, and seal the other ground joint of the flask;

[0090] S7. Place the flask in a water bath and heat the water in the water bath using an electric heating device to raise the temperature of the mixed solution in the flask to 65°C. The re-condensation device installed on the corresponding ground joint is connected to the circulating cooling water through the two ports. Annealing is carried out by re-condensation for 15 hours to complete the annealing.

[0091] Comparative Example 1

[0092] Except for step S4, where the mass fraction of tellurium tetrachloride in the mixed solution is 6%, the rest is the same as in Example 1.

[0093] Comparative Example 2

[0094] Except for step S7, in which the mixed solution in the flask is heated to 75°C, the rest is the same as in Example 1.

[0095] Comparative Example 3

[0096] Except for the annealing time of 25 hours in step S7, the rest is the same as in Example 1.

[0097] Comparative Example 4

[0098] Comparative Example 4 was conducted using the following steps:

[0099] Sa, InSb crystals are grown using the Czochralski method, which employs the following sub-steps:

[0100] Sa1, the 7.5N InSb polycrystalline material purified by zone melting, is cleaned with aqua regia and then subjected to a process called deionization.

[0101] Rinse with water at least 3 times, then dry in a vacuum oven for later use;

[0102] Sa2, fill the quartz crucible with a well-mixed, dried InSb polycrystalline material and Te powder.

[0103] Inside the crucible, the mass ratio of Te powder to InSb polycrystalline material is 1 mg: 10 kg;

[0104] Sa3. The Czochralski crystal growth equipment is evacuated, degassed, and leak-checked to achieve a vacuum. The vacuum pressure is below 10 Pa (monitored by a pressure gauge (not shown)). Evacuation and degassing are performed alternately 2-3 times using a vacuum pump and nitrogen filling. The vacuum port is located at the bottom of the Czochralski crystal growth equipment. Nitrogen (7N purity) is used for degassing.

[0105] The gas inlet is located at the top of the Czochralski crystal growth equipment;

[0106] Sa4: After sub-step Sa3 is completed, the top cover and the middle cylinder are locked with the corresponding screws, and the middle cylinder and the base are locked with the corresponding screws. After that, the vacuum port and the gas inlet are closed.

[0107] Sa5, reopen the gas inlet and purge the nitrogen-hydrogen mixture into the Czochralski crystal growth equipment to bring the pressure inside the equipment to 0.1 MPa (monitored by a pressure gauge), then close the gas inlet.

[0108] Sa6, heating is initiated on the quartz crucible to melt the InSb polycrystalline material and Te powder inside. The heater comprises a graphite heater, a double-layer graphite insulation cover, and carbon felt. The graphite heater surrounds the crucible, and the double-layer graphite insulation cover surrounds the graphite heater. The carbon felt fills the space between the inner and outer layers of the double-layer graphite insulation cover. The heater for heating the quartz crucible is...

[0109] The only heating device in the Lafarge crystal growth equipment;

[0110] Sa7, when the pressure inside the Czochralski crystal growth apparatus where InSb polycrystalline material and Te powder have completely melted to form a melt is increased to 0.15 MPa (monitored by a pressure gauge), the temperature of the quartz crucible is kept constant. The formation of the melt is observed through an observation window (not shown, located on the top cover).

[0111] In step Sa8, following sub-step Sa7, the pulling rod moves the seed crystal downwards into the quartz crucible, immersing it from the melt surface. The pulling rod then pulls the crystal upwards to grow a crystal rod. During crystal growth, the quartz crucible and the pulling rod maintain opposite rotational speeds: the crucible rotates at 1 rpm, and the pulling rod rotates at 3 rpm. The seed crystal is a 7.5N purity indium antimonide single crystal, and the pulling speed is constant.

[0112] Set at 5mm / h;

[0113] After Sa9 crystal growth is complete, heating is stopped, the temperature is lowered, and the gas inside the Czochralski crystal growth equipment is replaced with nitrogen again via a vacuum pump through the vacuum port and gas inlet.

[0114] The Czochralski crystal growth equipment cuts the crystal rod from the pulling rod;

[0115] Sb is prepared by diamond single-wire cutting to slice InSb crystals into InSb wafers.

[0116] In Comparative Example 4, steps S3 to S7 of Example 1 were not used; Te doping was performed directly on the InSb crystal grown by the Czochralski method.

[0117] Figure 3 This is a carrier concentration distribution diagram of the head slice of the InSb ingot grown by the Czochralski method in Example 1. Figure 4 This is a carrier concentration distribution map of a slice at the tail end of the InSb ingot grown by the Czochralski method in Example 1. The carrier concentration distribution was plotted using an HL9900 from Toho Technology, USA.

[0118] from Figure 3 and Figure 4 It can be seen that the carrier distribution in both the head and tail sections of the InSb crystal is lower than 2E14 / cm. 3 This reflects that the carrier density of the InSb crystal in the middle section between the head and tail of the InSb crystal rod is also lower than 2E14 / cm. 3 This satisfies the requirements of step S1 in Example 1.

[0119] Figure 5 This is a carrier concentration distribution diagram of the InSb wafer in Example 1 after annealing. Figure 6This is a signal response diagram of the InSb detector after the annealed InSb wafer of Example 1 was fabricated into an InSb infrared focal plane detector. Figure 10 This is a carrier concentration distribution diagram of the InSb wafer fabricated from the InSb ingot grown by the Czochralski method in Comparative Example 4. Figure 11 This is a signal response diagram of the InSb detector after fabrication of an InSb infrared focal plane detector using the InSb wafer of Comparative Example 4. The InSb detector signal response diagram is a level diagram of the fabricated InSb infrared focal plane detector after Dewar testing.

[0120] from Figure 5 and Figure 10 The comparison shows that, Figure 10 The carrier concentration distribution in Comparative Example 4 clearly exhibits an uneven distribution, with smaller concentrations at the top and larger concentrations at the bottom. Figure 5 In Example 1, the carrier concentration distribution is uniform. The carrier concentration non-uniformity is defined as (maximum value - minimum value) / average value. Figure 10 The carrier concentration inhomogeneity of Comparative Example 4 was 73.82%. Figure 5 The carrier concentration non-uniformity of Example 1 was 4.46%. That is, compared with Comparative Example 4, Example 1 achieved the purpose of uniform doping, that is, improved the doping uniformity of the indium antimonide wafer.

[0121] from Figure 6 and Figure 11 The comparison shows that, Figure 11 In Comparative Example 4, the InSb wafer exhibits arc-shaped stripes in the InSb detector signal response diagram after fabrication of an InSb infrared focal plane detector. Figure 6 In Example 1, the annealed InSb wafer showed no stripes in the InSb detector signal response diagram after fabrication of the InSb infrared focal plane detector. This means that Example 1 ensured the performance of the InSb detector fabricated from the indium antimonide wafer.

[0122] Figure 7 This is a diagram showing the carrier concentration distribution of the InSb wafer in Comparative Example 1 after annealing. Figure 7 In Comparative Example 1, the tellurium tetrachloride content was too high, resulting in a minimum carrier concentration of 2.10E15 / cm². 3 This is greater than the required 1.4E15 / cm. 3 ,also, Figure 7 The carrier concentration non-uniformity of Comparative Example 1 was 14.41%, therefore, the annealed InSb wafer of Comparative Example 1 could not be used to fabricate an InSb detector.

[0123] Figure 8 This is a diagram showing the carrier concentration distribution of the InSb wafer in Comparative Example 2 after annealing. Figure 8The annealing temperature of Comparative Example 2 was too high, resulting in a minimum carrier concentration distribution of 1.75E15 / cm². 3 This is greater than the required 1.4E15 / cm. 3 ,also, Figure 8 The carrier concentration non-uniformity of Comparative Example 2 was 12.45%, therefore, the annealed InSb wafer of Comparative Example 2 could not be used to fabricate an InSb detector.

[0124] Figure 9 This is a diagram showing the carrier concentration distribution of the InSb wafer in Comparative Example 3 after annealing. Figure 9 The annealing time of Comparative Example 3 was too long, resulting in a minimum carrier concentration distribution of 1.46E15 / cm. 3 This is greater than the required 1.4E15 / cm. 3 ,also, Figure 9 The carrier concentration non-uniformity of Comparative Example 3 was 11.58%, therefore, the annealed InSb wafer of Comparative Example 3 could not be used to fabricate an InSb detector.

[0125] Several exemplary embodiments have been described in detail above, but this document is not intended to limit itself to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined to form several other combinations, which are not shown for simplicity.

Claims

1. A method of annealing an indium antimonide wafer, characterized by, The method comprises the steps of: S1, Te-undoped InSb crystals with a carrier concentration of 2E14 / cm3 are grown by the Czochralski method 3 InSb crystals as follows; S2, cutting the InSb crystal into slices as InSb wafers; S3, grinding and polishing the InSb wafers; S4, adding a mixed solution of ethanol and tellurium tetrachloride into the flask through one grinding mouth of the flask, the mass fraction of the tellurium tetrachloride in the mixed solution being 1-5%, and the other grinding mouth of the flask being used for installing a recondensation device; S5, putting the InSb wafers after grinding and polishing into the mixed solution in the flask through one grinding mouth and completely immersing the InSb wafers in the mixed solution; S6, installing the recondensation device on the corresponding grinding mouth of the flask and blocking the other grinding mouth of the flask; S7, heating the mixed solution in the flask to 60-70℃ and annealing for 10-20 hours by recondensation to complete the annealing.

2. The annealing method of the InSb wafer according to claim 1, wherein, In step S1, the Czochralski method comprises the following sub-steps: S11, crushing the 7.5N InSb polycrystal material after zone refining, cleaning with aqua regia, rinsing with deionized water for more than 3 times, and drying in a vacuum oven for standby; S12, loading the InSb polycrystal material dried for standby into a quartz crucible; S13, vacuumizing, purging and leak testing the crystal growth equipment to achieve a vacuum in the crystal growth equipment, the pressure of the vacuum being less than 10 Pa, the vacuumizing and purging being alternately performed 2-3 times, the vacuumizing interface being arranged at the bottom of the crystal growth equipment, the purging being performed by nitrogen, and the nitrogen inlet being arranged at the top of the crystal growth equipment; S14, after the completion of the sub-step S13, locking the top cover and the middle cylinder by corresponding screws, locking the middle cylinder and the base by corresponding screws, and then closing the vacuumizing interface and the gas inlet; S15, opening the gas inlet again, filling the nitrogen-hydrogen mixed gas into the crystal growth equipment to make the pressure in the crystal growth equipment reach 0.1 MPa, and then closing the gas inlet; S16, opening the heating of the quartz crucible, and heating and melting the InSb polycrystal material in the quartz crucible, wherein the heater comprises a graphite heater, a graphite double-layer insulation cover and carbon felt, the graphite heater is arranged around the crucible, the graphite double-layer insulation cover is arranged around the graphite heater, and the carbon felt is filled between the inner layer and the outer layer of the graphite double-layer insulation cover, the heater for heating the quartz crucible being the only heating device in the crystal growth equipment; S17, maintaining the temperature of the quartz crucible unchanged when the pressure in the crystal growth equipment rises to 0.15 MPa after the InSb polycrystal material is completely melted to form a melt, and the formation of the melt is determined by observation through an observation window; S18, after the sub-step S17, moving the seed crystal into the quartz crucible by the pulling rod, immersing the seed crystal into the melt, and then performing crystal growth by the pulling rod to form a crystal rod, the quartz crucible and the pulling rod maintaining opposite rotating speeds during the crystal growth, the rotating speed of the crucible being 1 rpm and the rotating speed of the pulling rod being 3 rpm, the seed crystal being a 7.5N InSb single crystal, and the pulling speed being constant at 5 mm / h. S19, after the crystal growth is completed, stop heating, cooling, and again replacing the gas in the pulling crystal growth equipment with nitrogen through the vacuum pump via the vacuum interface and the gas inlet, then open the pulling crystal growth equipment, and cut the crystal rod from the crystal pulling rod.

3. The annealing method of the indium antimonide wafer according to claim 1, wherein, In step S2, the InSb crystal is sliced by using a diamond single-wire saw.

4. The annealing method of the indium antimonide wafer according to claim 1, wherein, In step S3, the grinding and polishing are performed by using a double-sided grinding machine.

5. The annealing method of the indium antimonide wafer according to claim 4, wherein, In step S3, the grinding and polishing are performed by using a polishing liquid prepared by mixing SiO2 sol and pure water at room temperature at a volume ratio of 1:1, and the grinding and polishing time is 30 s.

6. The annealing method of the indium antimonide wafer according to claim 1, wherein, In step S7, the temperature is raised by using a water bath.

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