Controllable atmosphere heat treatment device for tellurium-zinc-cadmium crystal square sheet

Abstract

The utility model relates to the field of tellurium-zinc-cadmium crystal heat treatment, and discloses a controllable atmosphere heat treatment device for tellurium-zinc-cadmium crystal square pieces, which comprises a quartz tube body, a quartz tube cavity is arranged in the quartz tube body, a workbench is arranged in the quartz tube cavity, a stainless steel water-cooling jacket is arranged on the outer wall of the quartz tube body, and the stainless steel water-cooling jacket is arranged on the outer wall of the quartz tube body. And the top surface of the upper sealing flange is communicated with a Te / Ar mixed gas pipeline. According to the utility model, the quartz tube body, the quartz tube cavity, the stainless steel water cooling jacket, the sealing flange and the Te / Ar mixed gas pipeline are matched for use, so that the problem of volatilization of tellurium element at high temperature can be effectively solved, the stability of the stoichiometric ratio of the CZT wafer is ensured, and the uniformity and the performance of the wafer are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of heat treatment of cadmium zinc telluride crystals, in particular to a controllable atmosphere heat treatment device for cadmium zinc telluride crystal square pieces. Background Art

[0002] Cadmium zinc telluride (CZT) crystals, as an important semiconductor material, are widely used in radiation detection, medical imaging, X-ray imaging, nuclear medicine, radiation metrology, and other fields. They are particularly valuable in high-energy physics, environmental monitoring, and security. The core advantages of CZT crystals in these applications include their high atomic number, strong photoelectric conversion efficiency, and excellent radiation detection capabilities. CZT crystals typically require heat treatment to improve their properties.

[0003] Currently, most CdZnTe crystal wafers are heat-treated without optimizing the sealing and atmosphere control to address the high volatility of tellurium. Consequently, the following disadvantages exist: tellurium easily evaporates at high temperatures, making it impossible to ensure the stoichiometric stability of the CZT wafer, resulting in reduced wafer uniformity and performance. Utility Model Content

[0004] The purpose of the utility model is to provide a controlled atmosphere heat treatment device for cadmium zinc telluride crystal square pieces, so as to solve the problem that tellurium element is easy to volatilize at high temperature, thereby failing to ensure the stoichiometric ratio stability of CZT wafers, resulting in reduced wafer uniformity and performance.

[0005] In order to achieve the above-mentioned purpose of the utility model, the utility model adopts the following technical solution: a controlled atmosphere heat treatment device for a square piece of cadmium zinc telluride crystal, comprising a quartz tube body, the interior of the quartz tube body being a quartz tube cavity, a workbench being provided inside the quartz tube cavity, a support rod being fixed to the bottom surface of the workbench, a stainless steel water-cooling jacket being provided on the outer wall of the quartz tube body, the top and bottom ends of the quartz tube body being connected to sealing flanges, the top surface of the upper sealing flange being connected to a Te / Ar mixed gas pipeline, and a first metal gallium being provided at the top interface of the Te / Ar mixed gas pipeline.

[0006] Preferably, the top surface of the upper sealing flange is connected to a zinc vapor injection pipeline, and a second metal gallium is provided at the top interface of the zinc vapor injection pipeline.

[0007] Preferably, the interior of the quartz tube cavity is divided into an upper temperature zone, a middle temperature zone and a lower temperature zone, and a heater is provided between the quartz tube body and the stainless steel water-cooling jacket.

[0008] Preferably, the bottom surface of the lower sealing flange is connected to an air outlet pipeline, and a third metal gallium is provided at the bottom interface of the air outlet pipeline.

[0009] Preferably, the Te / Ar mixed gas pipeline is used to connect to a tellurium saturated vapor compensation device, and the zinc vapor injection pipeline is used to connect to a zinc vapor injection module. Preferably, sealing rings are provided inside the two sealing flanges.

[0010] Compared with the prior art, the controlled atmosphere heat treatment device for a square piece of CdZnTe crystal using the above technical solution has the following beneficial effects:

[0011] 1. During use, the coordinated use of the quartz tube body, quartz tube cavity, stainless steel water-cooling jacket, sealing flange and Te / Ar mixed gas pipeline can effectively solve the volatilization problem of tellurium element at high temperature, ensure the stability of the stoichiometric ratio of the CZT wafer, and improve the uniformity and performance of the wafer;

[0012] 2. During use, during the zinc vapor injection phase, zinc vapor concentration is precisely regulated through zinc vapor injection line 6, effectively suppressing zinc segregation and ensuring the compositional stability of the CZT wafer during heat treatment. This not only improves wafer uniformity but also provides a strong guarantee for subsequent precision machining. Independent temperature control (ΔT ≤ 2°C / cm) is implemented in the upper, middle, and lower axial zones to ensure temperature uniformity during the heat treatment process. Furthermore, the radially added edge compensation heating module effectively eliminates the 10mm edge temperature difference, reducing the accumulation of thermal stress and, consequently, the proliferation of dislocations induced by thermal stress. This not only improves the wafer heat treatment effect but also provides a more stable wafer foundation for subsequent precision machining.

[0013] During operation, the exhaust pipe provides a convenient exhaust channel for the device. During the heat treatment process, the atmosphere within the chamber undergoes certain changes as the temperature rises and the atmosphere changes. The exhaust pipe allows for the timely removal of exhaust gases, maintaining the stability and purity of the chamber atmosphere. It also facilitates subsequent maintenance and cleaning. The Te / Ar mixed gas line and the zinc vapor injection line are connected to the tellurium saturated vapor compensation device and the zinc vapor injection module, respectively, establishing a dynamic atmosphere control system. PID control allows for precise adjustment of the zinc / tellurium partial pressure ratio to within ±0.5%. This not only improves the accuracy and stability of atmosphere control, but also provides a more stable and controllable environment for heat treatment of CZT wafers. The stainless steel water-cooling jacket activates when the temperature drops below 400°C. Combined with a helium jet (quenching rate ≥ 50°C / s), this allows the wafer to quickly pass through the brittle temperature range (400°C-200°C). This not only improves quenching efficiency but also ensures rapid cooling and stable performance of the CZT wafer. The sealing ring further improves the sealing performance of the quartz tube body. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is an overall cross-sectional schematic diagram of the embodiment.

[0015] 1. Quartz tube body; 2. Quartz tube cavity; 3. Workbench; 4. Stainless steel water-cooling jacket; 5. Te / Ar mixed gas pipeline; 6. Zinc vapor injection pipeline; 7. Upper temperature zone; 8. Middle temperature zone; 9. Lower temperature zone; 10. Heater; 11. Gas outlet pipeline; 12. Support rod; 13. Sealing flange; 14. Sealing ring; 15. First metal gallium; 16. Second metal gallium; 17. Third metal gallium. DETAILED DESCRIPTION

[0016] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0017] like Figure 1 As shown, a controlled atmosphere heat treatment device for a square piece of cadmium zinc telluride crystal includes a quartz tube body 1. The interior of the quartz tube body 1 is a quartz tube cavity 2. The interior of the quartz tube cavity 2 is provided with a workbench 3. A support rod 12 is fixed to the bottom surface of the workbench 3. The outer wall of the quartz tube body 1 is provided with a stainless steel water-cooling jacket 4. The top and bottom ends of the quartz tube body 1 are connected to sealing flanges 13. The top surface of the upper sealing flange 13 is connected to a Te / Ar mixed gas pipeline 5. A first metal gallium 15 is provided at the top interface of the Te / Ar mixed gas pipeline 5. The first metal gallium 15 is used to seal the connection between the Te / Ar mixed gas pipeline 5 and the pipeline.

[0018] In use, when processing a 50mm×50mm×1.2mm CZT wafer with x=0.1, the device has a quartz tube cavity 2 as the inner layer and a stainless steel water-cooling jacket 4 as the outer layer, and the Te / Ar mixed gas pipeline 5 is connected to the pipeline. The first metal gallium 15 utilizes its low melting point (29.8°C) and excellent wettability to form a liquid at room temperature or slightly heated conditions, filling the tiny gap between the Te / Ar mixed gas pipeline 5 and the pipeline. After cooling, a tight seal is formed, forming a double-sealed heat treatment chamber.

[0019] The inner quartz tube cavity 2 effectively reduces the reaction between the material and the cavity at high temperature, especially its resistance to Cd vapor corrosion, ensuring the purity of the processing environment. The outer stainless steel water-cooling jacket 4 provides rapid quenching capability. At the same time, the liquid seal of the first metal gallium 15 at the interface ensures the sealing of the entire system.

[0020] The staff can place the crystal on the workbench 3 and support it with the support rod 12, and then seal the top and bottom ends of the quartz tube 1 through the sealing flange 13. During the heating process, the temperature is first raised to 650℃ at a rate of 3℃ / min. At this time, the Te / Ar mixed gas pipeline 5 with a partial pressure ratio of 1:100 is introduced to replenish the tellurium element that may volatilize due to high temperature in real time, thereby maintaining the Cd-Te partial pressure balance and effectively avoiding the imbalance of the stoichiometric ratio. After keeping warm for 4 hours, the gradient cooling program is started, and the temperature is reduced at a rate of 0.5℃ / min from 650℃ to 400℃ to suppress the segregation of Zn. Below 400℃, the stainless steel water cooling jacket 4 is opened for rapid quenching. In this process, not only the stoichiometric ratio of the CZT chip is ensured to be stable, but also the quality of the chip is improved through precise temperature control. The coordinated use of the quartz tube body 1, the quartz tube cavity 2, the stainless steel water-cooling jacket 4 and the Te / Ar mixed gas pipeline 5 can effectively solve the volatilization problem of the tellurium element at high temperature, ensure the stability of the stoichiometric ratio of the CZT wafer, and improve the uniformity and performance of the wafer.

[0021] like Figure 1 As shown, the top surface of the upper sealing flange 13 is connected to the zinc vapor injection pipeline 6, and the top interface of the zinc vapor injection pipeline 6 is provided with a second metal gallium 16.

[0022] During use, during the zinc vapor injection stage, the zinc vapor concentration is precisely adjusted through the zinc vapor injection pipeline 6, effectively suppressing zinc segregation and ensuring the composition stability of the CZT wafer during the heat treatment process. This not only improves the uniformity of the wafer, but also provides a strong guarantee for subsequent precision processing. The second metal gallium 16 is used to fill the tiny gap between the zinc vapor injection pipeline 6 and the pipeline, forming a tight seal after cooling.

[0023] like Figure 1 As shown, the interior of the quartz tube cavity 2 is divided into an upper temperature zone 7, a middle temperature zone 8 and a lower temperature zone 9. A heater 10 is provided between the quartz tube body 1 and the stainless steel water-cooling jacket 4. The bottom surface of the sealing flange 13 below is connected to an outlet pipe 11, and a third metal gallium 17 is provided at the bottom interface of the outlet pipe 11.

[0024] During use, the axially divided upper, middle, and lower zones are independently temperature-controlled to a ΔT ≤ 2°C / cm, ensuring temperature uniformity of the wafer during heat treatment. Simultaneously, the radially added edge compensation heating module effectively eliminates the 10mm edge temperature difference, reducing the accumulation of thermal stress and, consequently, the proliferation of dislocations induced by thermal stress. This not only improves the heat treatment effect of the wafer but also provides a more stable wafer foundation for subsequent precision machining. The exhaust pipe 11 facilitates providing a convenient exhaust channel for the device. During the heat treatment process, as the temperature rises and the atmosphere changes, the gas in the chamber undergoes certain changes. The exhaust pipe 11 allows for timely exhaust of the exhaust gas from the chamber, maintaining the stability and purity of the atmosphere within the chamber and facilitating subsequent maintenance and cleaning.

[0025] To further ensure the sealing of the heat treatment chamber, a third metal, gallium 17, fills the tiny gap between the outlet pipe 11 and the tube. After cooling, a dense seal is formed. This design not only improves the overall sealing of the device but also effectively prevents the volatilization of tellurium during high-temperature treatment, improving the stoichiometric stability of the CZT wafer.

[0026] like Figure 1 As shown, the Te / Ar mixed gas pipeline 5 is used to connect to the tellurium saturated vapor compensation device, the zinc vapor injection pipeline 6 is used to connect to the zinc vapor injection module, and the two sealing flanges 13 are both provided with sealing rings 14 inside.

[0027] During use, the Te / Ar mixed gas pipeline 5 and the zinc vapor injection pipeline 6 are connected to the tellurium saturated vapor compensation device and the zinc vapor injection module, respectively, realizing the construction of a dynamic atmosphere control system. Through PID control, the zinc / tellurium partial pressure ratio can be precisely adjusted, with its error controlled within ±0.5%. This not only improves the accuracy and stability of atmosphere control, but also provides a more stable and controllable environment for the heat treatment of CZT wafers. The stainless steel water-cooling jacket 4 is activated when the temperature drops below 400°C. Combined with the helium jet device with a quenching rate of ≥50°C / s, it allows the wafer to quickly pass through the brittle temperature range of 400°C to 200°C, not only improving quenching efficiency but also providing a strong guarantee for the rapid cooling and stable performance of the CZT wafer. The sealing ring 14 further improves the sealing performance of the quartz tube 1.

[0028] To control and measure Te concentration, the device precisely regulates Te vapor pressure through overall temperature control. Based on known vapor pressure equations, such as the Antoine equation or the Clausius-Clapeyron equation, Te concentration can be calculated at different temperatures.

[0029] Specifically, the relationship between the vapor pressure P of Te and the temperature T can be expressed as:

[0030] Log10 P(mmHg)=AB / T(K)

[0031] in:

[0032] A≈7.6-8.2;

[0033] B≈7000-8000;

[0034] This formula can be used as a basis for adjusting the pressure and Te concentration of Te / Ar mixed gas pipeline 5 to ensure a stable atmosphere during the heat treatment process.

[0035] The above description is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention within the technical scope disclosed by the present invention, and they should be covered by the protection scope of the present invention.

Claims

1. A controlled atmosphere heat treatment device for a square piece of cadmium zinc telluride crystal, comprising a quartz tube (1), characterized in that: The interior of the quartz tube body (1) is a quartz tube cavity (2), a workbench (3) is provided inside the quartz tube cavity (2), a support rod (12) is fixed to the bottom surface of the workbench (3), the outer wall of the quartz tube body (1) is provided with a stainless steel water-cooling jacket (4), the top and bottom ends of the quartz tube body (1) are connected to a sealing flange (13), the top surface of the upper sealing flange (13) is connected to a Te / Ar mixed gas pipeline (5), and a first metal gallium (15) is provided at the top interface of the Te / Ar mixed gas pipeline (5).

2. The controlled atmosphere heat treatment apparatus for a CdZnTe crystal wafer according to claim 1, characterized in that: The top surface of the upper sealing flange (13) is connected to a zinc vapor injection pipeline (6), and a second metal gallium (16) is provided at the top interface of the zinc vapor injection pipeline (6).

3. The controlled atmosphere heat treatment apparatus for a CdZnTe crystal wafer according to claim 2, characterized in that: The interior of the quartz tube cavity (2) is divided into an upper temperature zone (7), a middle temperature zone (8) and a lower temperature zone (9), and a heater (10) is provided between the quartz tube body (1) and the stainless steel water-cooling jacket (4).

4. The controlled atmosphere heat treatment apparatus for a CdZnTe crystal wafer according to claim 3, characterized in that: The bottom surface of the sealing flange (13) below is connected to an air outlet pipeline (11), and a third metal gallium (17) is provided at the bottom interface of the air outlet pipeline (11).

5. The controlled atmosphere heat treatment apparatus for a CdZnTe crystal square wafer according to claim 2, characterized in that: The Te / Ar mixed gas pipeline (5) is used to connect to the tellurium saturated vapor compensation device, and the zinc vapor injection pipeline (6) is used to connect to the zinc vapor injection module.

6. The controlled atmosphere heat treatment apparatus for a CdZnTe crystal wafer according to claim 5, characterized in that: A sealing ring (14) is provided inside each of the two sealing flanges (13).

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