A gallium antimonide single crystal with electrically conductive performance precisely regulated by tellurium doping and a preparation method thereof

Abstract

The present application relates to a kind of by tellurium doped accurately regulated conduction performance gallium antimonide single crystal and its preparation method, the preparation method includes the following steps: Sb powder, Ga liquid and dopant Te powder are mixed and vacuum sealed, calcination, cooling, grinding, obtain polycrystalline powder;Self-fluxing Ga liquid is added to the polycrystalline powder, vacuum sealed, calcination, temperature reduction, centrifugal, obtain by tellurium doped accurately regulated conduction performance gallium antimonide single crystal.The present application uses gallium (Ga) as self-fluxing to grow Te-doped GaSb single crystal, the thermal stress of grown GaSb crystal is smaller, more uniform, by doping different content of Te element, can accurately regulate GaSb single crystal conduction type, carrier concentration and conduction performance, to improve the mobility of GaSb single crystal, to meet the application demand.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials technology, and in particular to a gallium antimonide single crystal with precisely controlled conductivity through tellurium doping and its preparation method. Background Technology

[0002] III-V compound semiconductor materials have attracted widespread attention due to their advantages in optoelectronic device applications. Antimonide infrared optoelectronic devices, with their excellent performance, show great application potential in infrared imaging, medical diagnostics, resource exploration, gas detection, optical communication, and thermophotovoltaics, becoming a current research hotspot. Gallium antimonide (GaSb) is an important III-V compound semiconductor material with a zincblende crystal structure, a lattice constant of 0.60959 nm, and a melting point as high as 710℃. It exhibits excellent electrical properties such as electron mobility, minority carrier lifetime, and bandgap. Furthermore, GaSb's direct bandgap characteristic makes it widely applicable in infrared detectors, solar cells, and high-speed electronic devices. However, due to the inherent physical properties of GaSb, undoped GaSb crystals typically exhibit p-type semiconductor characteristics, which limits its application in n-type conductivity applications. Therefore, how to effectively control the conductivity of GaSb single crystals through doping has become a current research hotspot. Studies have shown that Te-doped GaSb single crystals have the highest electron mobility among all GaSb-doped crystals to date, with an electron mobility reaching up to 5000 cm⁻¹. 2 With a doping density of / Vs, GaSb exhibits a significantly lower room-temperature resistivity compared to its parent material, resulting in enhanced conductivity. Doping introduces impurity energy levels into the GaSb crystal, effectively reducing the band gap of the doped system and making it easier for electrons to be excited from the valence band to the conduction band, thus altering its conductivity. However, the doping concentration is crucial to the material's properties; too much or too little doping can prevent achieving the desired conductivity, thereby affecting its application in devices. Therefore, precisely controlling the conductivity type and optimizing the conductivity of GaSb through doping techniques is of great significance.

[0003] Through continuous research, current studies on GaSb single crystal doping growth mainly focus on the Czochralski method, the Bridgman method, and vertically oriented gradient solidification. The Czochralski method can produce high-quality, large-size single crystals and is currently the main growth method for large-scale production. However, the Czochralski process is relatively complex, requiring precise control of the melt temperature and pulling speed, placing high demands on equipment, including high-quality seed crystals and a precise temperature control system. Compared to the Czochralski method, the Bridgman method is simpler, easier to control, and has a faster growth rate. However, during crystal growth, the crystal nucleates directly in contact with the crucible wall, which can easily lead to the formation of complex polycrystalline phases, affecting crystal quality. Vertically oriented gradient solidification can grow high-quality single crystals with fewer defects and uniform density. Compared to the Czochralski and Bridgman methods, vertically oriented gradient solidification is more technically challenging and costly, requiring specialized equipment to achieve vertically oriented solidification, increasing process complexity. The main problems with doping GaSb crystals using these methods are uneven doping concentration, failure to achieve the target conductivity, and low yield rates. For example, in the Czochralski method, if the pulling speed is too fast or too slow, it can lead to uneven distribution of dopant elements in the crystal. Furthermore, since the Czochralski method requires seed crystal growth, the crystal growth direction also affects the axial and radial distribution of the dopant concentration. For example, in... <100> The radial distribution of the physical properties of directionally grown crystals is not axisymmetric. Therefore, the doped ingots have a concentration gradient distribution, and the concentration distribution at the head and tail of the ingot is uneven, resulting in different conductivity types and capabilities. Only a portion of the region can be utilized. Summary of the Invention

[0004] Based on this, the purpose of this invention is to provide a gallium antimonide single crystal with precisely controlled conductivity through tellurium doping and its preparation method. Gallium (Ga) is used as a self-fluxing flux to grow Te-doped GaSb single crystals. The grown GaSb crystals have lower and more uniform thermal stress. By doping with different amounts of Te, the conductivity type, carrier concentration and conductivity of the GaSb single crystal can be precisely controlled, thereby improving the mobility of the GaSb single crystal to meet application requirements.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention first provides a gallium antimonide single crystal with precisely controlled conductivity through tellurium doping and its preparation method, which includes the following steps: S1. Mix Sb powder, Ga liquid and dopant Te powder and vacuum seal, calcine, cool and grind to obtain polycrystalline powder; S2. Add self-fluxing Ga liquid to the polycrystalline powder, vacuum seal, calcine, cool, and centrifuge to obtain gallium antimonide single crystal with its conductivity precisely controlled by tellurium doping.

[0006] As a further improvement to the above-described scheme of the present invention, in step S1, the molar ratio of Sb powder, Ga liquid, and Te powder is 1:1:x, where 0.000001≤x≤0.001. Since the saturated vapor pressure of antimony increases significantly with increasing temperature, leading to a faster volatilization rate, a slight excess of Sb is added during the preparation process to compensate for the Sb loss due to volatilization, thereby ensuring normal crystal growth and quality.

[0007] As a further improvement to the above-mentioned scheme of the present invention, in step S1, the calcination is carried out at 1000-1100℃ for 10-48h; and / or, the particle size of the polycrystalline powder is 10-40μm.

[0008] As a further improvement to the above-mentioned solution of the present invention, step S1, the mixing and vacuum sealing of Sb powder, Ga liquid and Te powder includes the following steps: in an argon-protected glove box, Sb powder, Ga liquid and Te powder are placed into a pretreated quartz crucible, and then the quartz crucible is placed in a quartz tube and vacuum sealed.

[0009] As a further improvement to the above-mentioned solution of the present invention, the pretreatment method of the quartz crucible is as follows: the quartz crucible is ultrasonically cleaned with deionized water, then cleaned with HNO3 solution with a concentration of 6%-8%, rinsed with deionized water, dried, and then kept at 800-1000℃ for 10-24 hours. It is then taken out with the furnace cooling process.

[0010] As a further improvement to the above-mentioned scheme of the present invention, in step S2, the molar ratio of the polycrystalline powder to the self-fluxing Ga liquid is 1:2-3.

[0011] As a further improvement to the above-mentioned solution of the present invention, in step S2, the calcination is carried out at 850-1000℃ for 10-24 hours.

[0012] As a further improvement to the above-mentioned solution of the present invention, in step S2, the cooling is carried out at a rate of 2-2.5℃ / h to 480-520℃.

[0013] As a further improvement to the above-mentioned scheme of the present invention, in step S2, the centrifugation speed is 1800-2000 r / min and the centrifugation time is 6-10 min.

[0014] The present invention also provides a gallium antimonide single crystal with precisely controlled conductivity through tellurium doping, which is prepared by the preparation method described above.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. In this invention, Sb powder, Ga liquid, and dopant Te powder are first mixed to synthesize polycrystalline powder, and then gallium is used as a self-fluxing flux for single crystal growth. During the polycrystalline synthesis stage, the various raw materials are fully mixed in the form of powder, which enables the dopant Te to be distributed relatively uniformly in the raw materials on a macroscopic scale. The synthesized polycrystalline ingot will form certain defects such as dislocations and impurities. By grinding it into powder, the original structure of the polycrystalline ingot can be broken, reducing the accumulation of impurities and defects. Then, based on the uniformly doped polycrystalline raw materials, single crystal growth can be carried out, which can ensure that the transfer of dopant from polycrystalline raw materials to single crystal is relatively uniform during the single crystal growth process, which is conducive to growing a single crystal with uniform doping and a more complete crystal structure.

[0016] 2. This invention uses gallium (Ga) as a self-fluxing flux to grow Te-doped GaSb single crystals. The self-fluxing flux method does not introduce other impurities and can overcome the problems of uneven composition during growth by methods such as the Czochralski method. The grown GaSb crystals have lower and more uniform thermal stress. This method can ensure the uniformity of the crystal when growing Te-doped GaSb single crystals. Furthermore, by doping with different amounts of Te, the conductivity type, carrier concentration, and conductivity of the GaSb single crystal can be precisely controlled, thereby improving the mobility of the GaSb single crystal to meet application requirements.

[0017] 3. This invention enables the growth of high-purity, low-defect-density GaSb single crystals via a self-flush method, which is crucial for improving device performance and reliability. By adjusting the Te doping concentration, the bandgap width of GaSb can be effectively controlled, thereby affecting its optoelectronic properties. As an N-type dopant, Te can significantly alter the conductivity of GaSb, transforming it from P-type to N-type, which is significant for specific applications such as infrared detectors. Furthermore, the equipment for the self-flush method is relatively simple; the crucible, heating element of the single-crystal furnace, and temperature measurement and control are all easily solved, facilitating implementation in both laboratory and industrial production. This is particularly important for guiding research into the intrinsic reasons for the improvement in GaSb crystal mobility caused by doping. Attached Figure Description

[0018] Figure 1 This is a photograph of a gallium antimonide single crystal obtained in Example 1, whose conductivity was precisely controlled by tellurium doping. Figure 2 This is a physical image of a gallium antimonide single crystal obtained in Example 2, whose conductivity was precisely controlled by tellurium doping. Figure 3 This is a physical image of a gallium antimonide single crystal obtained in Example 3, whose conductivity was precisely controlled by tellurium doping. Figure 4 This is a physical image of a gallium antimonide single crystal obtained in Example 4, whose conductivity was precisely controlled by tellurium doping. Figure 5This is a physical image of a gallium antimonide single crystal obtained in Example 5, whose conductivity was precisely controlled by tellurium doping. Figure 6 The images show the XRD patterns of gallium antimonide single crystals with precisely controlled conductivity through tellurium doping obtained in Examples 1-5. Figure 7 The XRD pattern of the polycrystalline powder obtained in step S3 of Examples 1-5; Figure 8 Gallium antimonide single crystals with precisely controlled conductivity via tellurium doping, as shown in Examples 1-2. ρ -T curve; Figure 9 This refers to the gallium antimonide single crystal prepared in Example 3, whose conductivity was precisely controlled by tellurium doping. ρ -T curve; Figure 10 Gallium antimonide single crystals with precisely controlled conductivity via tellurium doping, as shown in Examples 4-5. ρ -T curve; Figure 11 The Hall resistivity of gallium antimonide single crystals prepared in Examples 1-5, whose conductivity was precisely controlled by tellurium doping, is shown as a function of magnetic field strength. Detailed Implementation

[0019] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0021] Example 1 This embodiment proposes a method for preparing gallium antimonide single crystals with precisely controlled conductivity through tellurium doping, which includes the following steps: S1. Treatment of quartz crucible: Ultrasonically clean the crucible with deionized water for 10 minutes, then add 6%-8% HNO3 for cleaning, rinse with deionized water, dry the crucible, put it in a box furnace, heat to 1000℃ and keep it at that temperature for 10 hours, then remove it from the furnace and remove the moisture.

[0022] In actual operation, quartz crucibles may be contaminated in various ways, so they need to be cleaned in order to remove impurities and improve the accuracy of the experiment.

[0023] S2. Raw material ratio and packaging: In a glove box protected by high-purity argon (water content <0.1ppm and oxygen content <0.1ppm), weigh Ga liquid (purity: 99.9999%), Sb powder (purity: 99.9999%) and dopant Te powder (purity: 99.9999%) in a molar ratio of Ga:Sb:Te=1:1:0.000001, and place them into a pre-treated quartz crucible. Then, place the crucible filled with materials, filter gasket, inverted empty crucible and column head into a quartz tube with broken glass fragments at the bottom in sequence, and vacuum seal.

[0024] S3. Polycrystalline synthesis: The quartz tube is placed in a high-temperature box furnace and heated from room temperature to 1000℃ over 10 hours. The temperature is then maintained for 10 hours to allow the raw materials to mix thoroughly and react. The tube is then removed from the furnace and ground to obtain polycrystalline powder.

[0025] S4. Single crystal growth: Add 2 mol of Ga liquid (purity: 99.9999%) to the synthesized polycrystalline powder, seal under vacuum, raise the temperature from room temperature to 850 ℃ after 10 h, hold at that temperature for 10 h, and then lower the temperature to 520 ℃ at a rate of 2 ℃ / h, and wait for centrifugation.

[0026] S5. Centrifugation: Quickly remove the quartz tube from the high-temperature box furnace and place it in a centrifuge. Separate the crystal from the flux by high-speed centrifugation (2000 r / min, centrifugation time 6 min), thereby obtaining gallium antimonide single crystal GaSb with its conductivity precisely controlled by tellurium doping. 0.999999 Te 0.000001 The gallium antimonide single-crystal GaSb obtained in this embodiment has its conductivity precisely controlled through tellurium doping. 0.999999 Te 0.000001 Actual product image as shown Figure 1 As shown.

[0027] Example 2 This embodiment uses the same implementation method as Embodiment 1, except that in step S2, high-purity Sb powder (purity: 99.9999%), Ga liquid (purity: 99.9999%), and Te powder (purity: 99.9999%) are weighed in a molar ratio of Ga:Sb:Te = 1:1:0.000004, thereby obtaining gallium antimonide single crystal GaSb with precisely controlled conductivity through tellurium doping. 0.999996 Te 0.000004 The gallium antimonide single-crystal GaSb obtained in this embodiment has its conductivity precisely controlled through tellurium doping. 0.999996 Te 0.000004 Actual product image as shown Figure 2 As shown.

[0028] Example 3 This embodiment uses the same implementation method as Embodiment 1, except that in step S2, high-purity Sb powder (purity: 99.9999%), Ga liquid (purity: 99.9999%), and dopant Te powder (purity: 99.9999%) are weighed in a molar ratio of Ga:Sb:Te = 1:1:0.00001, thereby obtaining gallium antimonide single crystal GaSb with precisely controlled conductivity through tellurium doping. 0.99999 Te 0.00001 The gallium antimonide single-crystal GaSb obtained in this embodiment has its conductivity precisely controlled through tellurium doping. 0.99999 Te 0.00001 Actual product image as shown Figure 3 As shown.

[0029] Example 4 This embodiment uses the same implementation method as Embodiment 1, except that in step S2, high-purity Sb powder (purity: 99.9999%), Ga liquid (purity: 99.9999%), and dopant Te powder (purity: 99.9999%) are weighed in a molar ratio of Ga:Sb:Te = 1:1:0.0001, thereby obtaining gallium antimonide single crystal GaSb with precisely controlled conductivity through tellurium doping. 0.9999 Te 0.00001 The gallium antimonide single-crystal GaSb obtained in this embodiment has its conductivity precisely controlled through tellurium doping. 0.9999 Te 0.00001 Actual product image as shown Figure 4 As shown.

[0030] Example 5 This embodiment uses the same implementation method as Embodiment 1, except that in step S2, high-purity Sb powder (purity: 99.9999%), Ga liquid (purity: 99.9999%), and dopant Te powder (purity: 99.9999%) are weighed in a molar ratio of Ga:Sb:Te = 1:1:0.001, thereby obtaining gallium antimonide single crystal GaSb with precisely controlled conductivity through tellurium doping. 0.999 Te 0.001 The gallium antimonide single-crystal GaSb obtained in this embodiment has its conductivity precisely controlled through tellurium doping. 0.999 Te 0.001 Actual product image as shown Figure 5 As shown.

[0031] Test case 1. Structural characterization The concentration of gallium antimonide single crystals with precisely controlled conductivity through tellurium doping, prepared in Examples 1-5, was measured using inductively coupled plasma mass spectrometry (ICP). The actual contents of the dopant components in the gallium antimonide single crystals with precisely controlled conductivity through tellurium doping prepared in Examples 1-5 were x=8.75ppm, x=24.2ppm, x=137ppm, x=0.015%, and x=0.29%, respectively.

[0032] X-ray diffraction was performed on gallium antimonide single crystals with precisely controlled conductivity via tellurium doping obtained in Examples 1-5 and polycrystalline powders obtained in step S3, yielding the following results: Figure 6 The XRD pattern shown is of a gallium antimonide single crystal with precisely controlled conductivity through tellurium doping. Figure 7 The XRD pattern of the polycrystalline powder; compared with the standard PDF card (PDF#70-1918), the XRD of the polycrystalline powder shows that the doped sample has no impurities generated and is a pure phase; the XRD of the gallium antimonide single crystal whose conductivity is precisely controlled by tellurium doping shows that the doped sample is a single crystal and its natural growth surface is (111) plane.

[0033] 2. Electrical transmission test (1) ρ -T curve: ρ The -T curve can reflect the change of resistivity with temperature, thereby determining the basic physical properties of the sample (metal / semiconductor).

[0034] The gallium antimonide single crystals prepared in Examples 1-5, whose conductivity was precisely controlled by tellurium doping, were subjected to precise electrical transport tests using a low-temperature physical property measurement system (PPMS-9T, 1.8K≤T≤400K, 0≤H≤9T) to characterize their conductivity. The results are as follows: Figure 8-10 shown ρ -T curve.

[0035] from Figure 8-10 It can be seen that when the doping concentration is below 137 ppm, the tellurium-doped gallium antimonide single crystal exhibits semiconductor behavior; when the doping concentration is above 137 ppm, the tellurium-doped gallium antimonide single crystal exhibits metallic behavior. As the doping concentration increases, the resistivity decreases, and its conductivity increases by several orders of magnitude. The band gap can be controlled from present to absent, indicating that the tellurium-doped gallium antimonide single crystal grown by the self-flux method in this application can achieve control over the conductivity of the crystal by changing the Te doping concentration.

[0036] (2) Hall test Hall resistivity can be obtained through Hall testing. ρ xy The information requires measuring the Hall signals under both forward and reverse fields, subtracting the transverse resistance, to obtain the intrinsic Hall resistivity. ρxy =( ρ xy (B)- ρ xy (-B)) / 2. Using the formula: The Hall coefficient can be calculated. R H According to the formula: The carrier concentration can be calculated. n According to the formula: The mobility μ can be calculated. R H The sign of the symbol can reflect the conductivity type of the sample. R H >0 It is a p-type conductor. R H <0 It is an n-type conductor.

[0037] Electrode leads were fabricated using the seven-lead method. Electrical transport was measured on the tellurium-doped gallium antimonide single crystal samples prepared in Examples 1-5 under conditions of T=300K and B=1T. The test results are as follows: Figure 11 As shown in Table 1.

[0038] Table 1. Electrical performance values ​​of tellurium-doped gallium antimonide single crystal samples prepared in Examples 1-5 at 300K.

[0039] according to Figure 11 As shown in Table 1, controlling the Te doping content can alter the crystal's conductivity type and carrier concentration, thereby improving mobility. Within a suitable doping concentration range, mobility increases with increasing carrier concentration. This is because higher carrier concentration enhances conductivity and reduces scattering during carrier movement, thus increasing mobility. However, excessively high doping concentrations can lead to increased lattice distortion and impurity scattering, which conversely reduces mobility. Therefore, precise control of the Te doping content and processing conditions is necessary to achieve optimal performance.

[0040] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0041] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing gallium antimonide single crystals with precisely controlled conductivity through tellurium doping, characterized in that, It includes the following steps: S1. Mix Sb powder, Ga liquid and dopant Te powder and vacuum seal, the molar ratio of Sb powder, Ga liquid and Te powder is 1:1:x, 0.000001≤x≤0.001, calcine at 1000-1100℃ for 10-48h, cool and grind to obtain polycrystalline powder, the particle size of the polycrystalline powder is 10-40μm; S2. Add self-fluxing Ga liquid to the polycrystalline powder, wherein the molar ratio of the polycrystalline powder to the self-fluxing Ga liquid is 1:2-3, vacuum seal, calcine at 850-1000℃ for 10-24h, cool to 480-520℃ at a rate of 2-2.5℃ / h, centrifuge, and obtain gallium antimonide single crystal with its conductivity precisely controlled by tellurium doping.

2. The method for preparing gallium antimonide single crystals with precisely controlled conductivity through tellurium doping according to claim 1, characterized in that, In step S1, mixing Sb powder, Ga liquid, and dopant Te powder and vacuum sealing includes the following steps: In an argon-protected glove box, Sb powder, Ga liquid, and dopant Te powder are placed into a pretreated quartz crucible, and then the quartz crucible is placed in a quartz tube and vacuum sealed.

3. The method for preparing gallium antimonide single crystals with precisely controlled conductivity through tellurium doping according to claim 2, characterized in that, The pretreatment method for the quartz crucible is as follows: ultrasonically clean the quartz crucible with deionized water, then clean it with a 6%-8% HNO3 solution, rinse it with deionized water, wipe it dry, and then keep it at 800-1000℃ for 10-24 hours. After cooling in the furnace, it can be taken out.

4. The method for preparing gallium antimonide single crystals with precisely controlled conductivity through tellurium doping according to claim 1, characterized in that, In step S2, the centrifugation speed is 1800-2000 r / min, and the centrifugation time is 6-10 min.

5. A gallium antimonide single crystal with precisely controlled conductivity through tellurium doping, characterized in that, It is prepared by the preparation method described in any one of claims 1-4.

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