Gallium antimonide single crystal capable of accurately regulating and controlling conductivity through tellurium doping and preparation method of gallium antimonide single crystal

Abstract

The invention relates to a gallium antimonide single crystal capable of accurately regulating and controlling conductivity through tellurium doping and a preparation method thereof, and the preparation method comprises the following steps: mixing Sb powder, Ga liquid and dopant Te powder, and carrying out vacuum sealing, calcining, cooling and grinding to obtain polycrystalline powder; and adding a self-fluxing agent Ga liquid into the polycrystalline powder, and carrying out vacuum sealing, calcination, cooling and centrifugation to obtain the gallium antimonide single crystal with the conductivity accurately regulated and controlled through tellurium doping. Gallium (Ga) is adopted as a self-fluxing agent to grow the Te-doped GaSb single crystal, the thermal stress of the grown GaSb crystal is smaller and more uniform, and the conductivity type, the carrier concentration and the conductivity of the GaSb single crystal can be accurately regulated and controlled by doping Te elements with different contents, so that the mobility of the GaSb single crystal is improved, and the application requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor materials, and in particular to a gallium antimonide single crystal whose electrical conductivity can be precisely regulated by tellurium doping and a preparation method thereof. Background Art

[0002] III-V compound semiconductor materials have attracted extensive attention due to their advantages in the application of optoelectronic devices. Antimonide infrared optoelectronic devices have shown great application prospects in infrared imaging, medical diagnosis, resource exploration, gas detection, optical communication, thermophotovoltaics and other fields with their excellent performance, and have become a current research hotspot. Gallium antimonide is an important III-V compound semiconductor material with a zinc blende crystal structure, a lattice constant of 0.60959nm, and a melting point of up to 710℃. It has excellent electrical properties such as electron mobility, minority carrier lifetime and energy gap. In addition, the direct band gap characteristics of GaSb make it widely used in infrared detectors, solar cells and high-speed electronic devices. However, due to the inherent physical properties of gallium antimonide, undoped GaSb crystals usually exhibit p-type semiconductor characteristics, which limits its application in n-type conductive needs. Therefore, how to regulate the conductive properties of GaSb single crystals through effective doping methods has become a current research hotspot. Studies have shown that Te-doped GaSb single crystals have the highest mobility among GaSb-doped crystals, with an electron mobility of up to 5000 cm 2 / Vs, its room temperature resistivity is greatly reduced compared with the parent material, and its conductivity is enhanced. By doping, impurity energy levels are introduced into GaSb crystals, which effectively reduces the bandgap width of the doping system, making it easier for electrons to be excited from the valence band to the conduction band, changing its conductivity. However, the size of the doping content has a crucial impact on the material properties. Too much or too little doping content will result in the inability to obtain the target conductivity, thus affecting its application in devices. Therefore, it is of great significance to accurately control the conductivity type of GaSb and optimize its conductivity through doping technology.

[0003] After continuous research, the current research on the doping growth of GaSb single crystals is mainly focused on the Czochralski method, the Bridgman method and the vertical directional gradient solidification method. The Czochralski method can produce high-quality, large-sized single crystals and is the main growth method for large-scale production. However, the operation process of the Czochralski method is relatively complicated, requiring precise control of the temperature and pulling speed of the melt, and has high requirements for equipment, requiring high-quality seed crystals and precise temperature control systems. Compared with the Czochralski method, the Bridgman method is simpler, easier to control, and has a faster growth rate, but during its crystal growth process, it directly contacts the crucible wall for nucleation, and it is easy to form a complex polycrystalline phase during the growth process, which affects the crystal quality. The vertical directional solidification method can grow high-quality single crystals with fewer crystal defects and uniform density. Compared with the Czochralski method and the Bridgman method, the vertical directional gradient solidification method has higher technical difficulty and cost, and requires special equipment to achieve directional solidification in the vertical direction, which increases the complexity of the process. The main problem of doping GaSb crystals by the above methods is that the doping concentration is uneven, the target conductivity cannot be obtained, and the qualified rate is low. For example, in the Czochralski method, if the pulling speed is too fast or too slow, it may lead to uneven distribution of doping elements in the crystal. In addition, since the Czochralski method requires seed crystal growth, the growth direction of the crystal will also affect the axial and radial distribution of doping concentration. <100> The radial distribution of the physical properties of crystals grown in the same direction is not axisymmetric, so the ingot obtained by doping has a concentration gradient distribution. The concentration distribution at the head and tail of the ingot is uneven, which leads to different conductivity types and capabilities, and only part of the area can be utilized. Summary of the invention

[0004] Based on this, the purpose of the present invention is to provide a gallium antimonide single crystal with conductive properties precisely controlled by tellurium doping and a preparation method thereof, wherein gallium (Ga) is used as a self-flux to grow Te-doped GaSb single crystals, and the grown GaSb crystals have smaller thermal stress and are more uniform. By doping with different contents of Te elements, the conductive type, carrier concentration and conductive properties 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 object, the present invention adopts the following technical solutions: The present invention first provides a gallium antimonide single crystal with conductive properties precisely controlled by tellurium doping and a preparation method thereof, which comprises the following steps: S1. Sb powder, Ga solution and dopant Te powder are mixed and vacuum sealed, calcined, cooled and ground to obtain polycrystalline powder; S2. Adding a self-fluxing agent Ga liquid to the polycrystalline powder, vacuum sealing, calcining, cooling, and centrifuging to obtain a gallium antimonide single crystal whose conductive properties are precisely controlled by tellurium doping.

[0006] As a further improvement of the above scheme of the present invention, in step S1, the molar ratio of Sb powder, Ga liquid and Te powder is 1:1:x, 0.000001≤x≤0.001. Since the saturated vapor pressure of Sb will increase significantly with the increase of temperature, resulting in its volatilization speed to accelerate, Sb is slightly excessive during the batching to compensate for the Sb lost due to volatilization, thereby ensuring the normal growth and quality of the crystal.

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

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

[0009] As a further improvement of the above scheme of the present invention, the pretreatment method of the quartz crucible is: the quartz crucible is ultrasonically cleaned with deionized water, then cleaned with a HNO3 solution with a concentration of 6%-8%, then rinsed with deionized water, wiped dry, and then placed at 800-1000°C for 10-24h, and then taken out with the furnace cooling.

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

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

[0012] As a further improvement of the above solution of the present invention, in step S2, the temperature is lowered to 480-520°C at a rate of 2-2.5°C / h.

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

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

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention first mixes Sb powder, Ga liquid and dopant Te powder to synthesize polycrystalline powder, and then uses gallium as a self-flux agent to grow single crystals; in the polycrystalline synthesis stage, various raw materials are fully mixed in the form of powder, etc., so that the dopant Te can be distributed more evenly in the raw materials on a macroscopic level. The synthesized polycrystalline ingot will form certain defects such as dislocations and impurities. By grinding into powder, the original structure of the polycrystalline ingot can be broken, and the aggregation of impurities and defects can be reduced. Single crystal growth is then carried out based on the uniformly doped polycrystalline raw materials, which can ensure that during the single crystal growth process, the transfer of dopants from the polycrystalline raw materials to the single crystals is relatively uniform, which is conducive to the growth of single crystals with uniform doping and more complete crystal structures.

[0016] 2. The present invention uses gallium (Ga) as a self-flux to grow Te-doped GaSb single crystals. The self-flux method does not introduce other impurities and can overcome the problems of uneven components during the growth process of methods such as the Czochralski method. The grown GaSb crystals have smaller thermal stress and are more uniform. Growing Te-doped GaSb single crystals in this way can ensure the uniformity of the crystals, and by doping different contents of Te elements, the conductivity type, carrier concentration and conductivity of the GaSb single crystal can be accurately controlled, thereby improving the mobility of the GaSb single crystal to meet application requirements.

[0017] 3. The present invention can grow high-purity, low-defect density GaSb single crystals through the self-fluxing method, which is crucial to improving the performance and reliability of the device. By adjusting the doping concentration of Te, the band gap width of GaSb can be effectively regulated, thereby affecting its photoelectric performance. Te, as an N-type dopant, can significantly change the conductivity of GaSb, making it change from P-type to N-type, which is of great significance for specific applications such as infrared detectors. In addition, the equipment of the self-fluxing method is relatively simple, and the crucible and single crystal furnace heating element, temperature measurement and temperature control are easy to solve, which is helpful for implementation in laboratories and industrial production, especially for studying the intrinsic reasons for the improvement of GaSb crystal mobility by doping. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a physical picture of the gallium antimonide single crystal whose electrical conductivity is precisely controlled by tellurium doping obtained in Example 1; Figure 2 This is a physical picture of the gallium antimonide single crystal whose electrical conductivity is precisely controlled by tellurium doping obtained in Example 2; Figure 3 This is a physical picture of the gallium antimonide single crystal whose electrical conductivity is precisely controlled by tellurium doping obtained in Example 3; Figure 4 This is a physical picture of the gallium antimonide single crystal whose electrical conductivity is precisely controlled by tellurium doping obtained in Example 4; Figure 5This is a physical picture of the gallium antimonide single crystal whose electrical conductivity is precisely controlled by tellurium doping obtained in Example 5; Figure 6 The XRD diagram of the gallium antimonide single crystal whose electrical conductivity is precisely controlled by tellurium doping obtained in Example 1-5; Figure 7 is the XRD pattern of the polycrystalline powder obtained in step S3 of Example 1-5; Figure 8 The GaSb single crystal obtained in Example 1-2 with its conductive properties precisely controlled by tellurium doping ρ -T curve graph; Fig. 9 The GaSb single crystal obtained in Example 3, whose electrical conductivity is precisely controlled by tellurium doping, ρ -T curve graph; Fig.10 The GaSb single crystal obtained in Example 4-5 with its conductive properties precisely controlled by tellurium doping ρ -T curve graph; Fig.11 This is a graph showing the variation of the Hall resistivity of the gallium antimonide single crystal obtained in Examples 1-5 with the magnetic field strength, the conductivity of which is precisely controlled by tellurium doping. DETAILED DESCRIPTION

[0019] For ease of understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] Example 1 This embodiment provides a method for preparing a gallium antimonide single crystal with precise control of the conductive properties by tellurium doping, which comprises the following steps: S1. Treatment of quartz crucible: ultrasonically clean the crucible with deionized water for 10 minutes, then add HNO3 with a concentration of 6%-8% for cleaning, and then rinse with deionized water. Then wipe the crucible dry, put it in a box furnace, heat it to 1000℃ and keep it warm for 10 hours, take it out with the furnace cooling, and remove moisture.

[0022] During actual operation, the quartz crucible may be contaminated by various factors, so it needs to be cleaned to remove impurities and improve experimental accuracy.

[0023] S2. Raw material ratio and packaging: In a glove box protected by high-purity argon gas (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 put them into a pretreated quartz crucible. Then put the loaded crucible, filter gasket, inverted empty crucible and column head into a quartz tube with broken glass slag at the bottom in turn, and seal it in vacuum.

[0024] S3. Polycrystalline synthesis: Place the quartz tube in a high-temperature box furnace, first raise the temperature from room temperature to 1000°C over 10 hours, and keep it at this temperature for 10 hours to allow the raw materials to be fully mixed and react. Then, cool it down and take it out of the furnace, grind it, and obtain polycrystalline powder.

[0025] S4. Single crystal growth: Add 2 mol of Ga liquid (purity: 99.9999%) to the synthesized polycrystalline powder. After vacuum sealing, heat it from room temperature to 850 °C over 10 h. After keeping it at this temperature for 10 h, cool it down to 520 °C at a rate of 2 °C / h and wait for centrifugation.

[0026] S5. Centrifugation: The quartz tube in the high-temperature box furnace is quickly taken out and placed in a centrifuge. The crystal is separated from the flux by high-speed centrifugation (speed 2000 r / min, centrifugation time 6 min), thereby obtaining a gallium antimonide single crystal GaSb with precise control of conductive properties by tellurium doping. 0.999999 Te 0.000001 The GaSb single crystal obtained in this embodiment has a conductive property that is precisely controlled by tellurium doping. 0.999999 Te 0.000001 Actual picture Figure 1 shown.

[0027] Example 2 This embodiment adopts the same implementation method as that of Embodiment 1, and the difference from Embodiment 1 is that in this embodiment, 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 a gallium antimonide single crystal GaSb with conductive properties precisely controlled by tellurium doping. 0.999996 Te 0.000004 The GaSb single crystal obtained in this embodiment has a conductive property that is precisely controlled by tellurium doping. 0.999996 Te 0.000004 Actual picture Figure 2 shown.

[0028] Example 3 This embodiment adopts the same implementation as that of the embodiment 1, and the difference from the embodiment 1 is that in the present embodiment, 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 a gallium antimonide single crystal GaSb with conductive properties precisely controlled by tellurium doping. 0.99999 Te 0.00001 The GaSb single crystal obtained in this embodiment has a conductive property that is precisely controlled by tellurium doping. 0.99999 Te 0.00001 Actual picture Figure 3 shown.

[0029] Example 4 This embodiment adopts the same implementation as that of the embodiment 1, and the difference from the embodiment 1 is that in this embodiment, 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 a gallium antimonide single crystal GaSb with conductive properties precisely controlled by tellurium doping. 0.9999 Te 0.00001 The GaSb single crystal obtained in this embodiment has a conductive property that is precisely controlled by tellurium doping. 0.9999 Te 0.00001 Actual picture Figure 4 shown.

[0030] Example 5 This embodiment adopts the same implementation as that of the embodiment 1, and the difference from the embodiment 1 is that in this embodiment, 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, so as to obtain a gallium antimonide single crystal GaSb with conductive properties precisely controlled by tellurium doping. 0.999 Te 0.001 The GaSb single crystal obtained in this embodiment has a conductive property that is precisely controlled by tellurium doping. 0.999 Te 0.001 Actual picture Figure 5 shown.

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

[0032] The GaSb single crystals whose conductivity is precisely controlled by tellurium doping and obtained in Examples 1-5 and the polycrystalline powder obtained in step S3 are subjected to X-ray diffraction using an X-ray diffractometer to obtain the following: Figure 6 The XRD pattern of GaSb single crystal with precise control of conductivity by tellurium doping is shown in 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 and is a pure phase; the XRD of the gallium antimonide single crystal whose conductive properties are precisely controlled by tellurium doping shows that the doped samples are all single crystals, and their natural growth surface is the (111) surface.

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

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

[0035] from Figure 8-10 It can be seen that: when the doping concentration is below 137ppm, the tellurium-doped gallium antimonide single crystal exhibits semiconductor behavior; when the doping concentration is above 137ppm, 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, and the band gap is regulated from existence to non-existence, indicating that the tellurium-doped gallium antimonide single crystal grown by the self-flux method in this application can achieve regulation of the crystal conductivity by changing the Te doping concentration.

[0036] (2) Hall test Hall test can get Hall resistivity ρ xy Information, it is necessary to measure the Hall signal under the positive and negative fields and deduct the lateral resistance to obtain the intrinsic Hall resistivity ρxy =( ρ xy (B)- ρ xy (-B)) / 2. By 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 positive or negative value of can reflect the conductivity type of the sample. R H >0 , is p-type conductivity, R H <0 , which is n-type conductivity.

[0037] The electrode leads were made by the seven-lead method, and the electrical transport of the tellurium-doped gallium antimonide single crystal samples prepared in Examples 1-5 was measured under the conditions of T=300K and B=1T. The test results are shown in FIG. Fig.11 , as shown in Table 1.

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

[0039] according to Fig.11 As shown in the results in Table 1, by controlling the Te doping content, the conductivity type and carrier concentration of the crystal can be changed, thereby improving the mobility. Within the appropriate doping concentration range, as the carrier concentration increases, the mobility increases accordingly. This is because a higher carrier concentration can enhance conductivity and reduce the scattering of carriers during movement, thereby improving mobility. However, if the doping concentration is too high, it may lead to problems such as increased lattice distortion and increased impurity scattering, which will reduce mobility. Therefore, it is necessary to precisely control the Te doping content and process conditions to obtain the best performance.

[0040] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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 above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping, characterized in that: It includes the following steps: S1. Sb powder, Ga solution and dopant Te powder are mixed and vacuum sealed, calcined, cooled and ground to obtain polycrystalline powder; S2. Adding a self-fluxing agent Ga liquid to the polycrystalline powder, vacuum sealing, calcining, cooling, and centrifuging to obtain a gallium antimonide single crystal whose conductive properties are precisely controlled by tellurium doping.

2. The method for preparing a gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping according to claim 1, characterized in that: In step S1, the molar ratio of Sb powder, Ga solution and Te powder is 1:1:x, 0.000001≤x≤0.

001.

3. The method for preparing a gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping according to claim 1, characterized in that: In step S1, the calcination is carried out at 1000-1100° C. for 10-48 hours; and / or the particle size of the polycrystalline powder is 10-40 μm.

4. The method for preparing a gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping according to claim 1, characterized in that: In step S1, the mixing of 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 in a pretreated quartz crucible, and then the quartz crucible is placed in a quartz tube and vacuum sealed.

5. The method for preparing a gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping according to claim 4, characterized in that: The pretreatment method of the quartz crucible is: ultrasonically clean the quartz crucible with deionized water, then clean it with a HNO3 solution with a concentration of 6%-8%, rinse it with deionized water, wipe it dry, and then place it at 800-1000°C for 10-24h, and then take it out from the furnace after cooling.

6. The method for preparing a gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping according to claim 1, characterized in that: In step S2, the molar ratio of the polycrystalline powder to the self-fluxing agent Ga liquid is 1:2-3.

7. The method for preparing a gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping according to claim 1, characterized in that: In step S2, the calcination is carried out at 850-1000°C for 10-24h.

8. The method for preparing a gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping according to claim 1, characterized in that: In step S2, the temperature is lowered to 480-520°C at a rate of 2-2.5°C / h.

9. The method for preparing a gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping according to claim 1, characterized in that: In step S2, the centrifugal speed is 1800-2000 r / min, and the centrifugal time is 6-10 min.

10. A gallium antimonide single crystal with precise control of electrical conductivity by tellurium doping, characterized in that: The invention is prepared by the preparation method described in any one of claims 1 to 9.

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