Crystal growth crucible capable of accurately controlling temperature of Cd source

Abstract

The utility model belongs to the technical field of tellurium-zinc-cadmium single crystal growth process, and particularly relates to a crystal growth crucible capable of accurately controlling the temperature of a Cd source, which comprises a crystal growth crucible body, the bottom of the crystal growth crucible body is of an inward concave structure, and the inward concave structure enables the bottom of an inner cavity of the crystal growth crucible body to form first accommodating cavities positioned on two sides of the inward concave structure; the first containing cavity is filled with a Cd source. The Cd source liquid level temperature can be accurately controlled, the difference between different devices or different positions of the same device is avoided, the repeatability is completely controllable, and accurate control over cadmium zinc telluride inclusions can be achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of cadmium zinc telluride single crystal growth process, and in particular relates to a crystal growth crucible for accurately controlling the temperature of a Cd source. Background Art

[0002] CdZnTe single crystal is used as the material for making detectors or HgCdTe epitaxial substrates. The single crystal growth conditions are high temperature and high pressure. The crystal growth process commonly used in density space is: during the high-temperature growth process, the evaporation of the element causes the CdZnTe melt to deviate from the stoichiometric ratio, resulting in a tellurium-rich or cadmium-rich state of the melt, forming inclusions. The presence of inclusions seriously affects the performance of the detector or HgCdTe epitaxial substrate. Therefore, it is necessary to avoid or reduce the formation of inclusions during the growth process of CdZnTe single crystals as much as possible.

[0003] At present, the following methods are mainly used to reduce and control inclusions: use a separate Cd source, control the vapor pressure by independently controlling the temperature at the Cd source, and maintain the positive chemical balance of the melt: in this method, the Cd source temperature is independently controlled, and the stoichiometric ratio of the melt is accurately controlled by controlling the Cd source temperature during the growth process; during the cooling process, the Cd source temperature is controlled to anneal the ingot in a Cd atmosphere, which can better control inclusions, but in the production process, there are large differences in Cd source temperature between different equipment; there are obvious differences in inclusions at different positions of the ingot during the growth process of the same equipment; there are abnormal ingots with inclusions during the growth process (same process), and the repeatability reliability needs to be improved.

[0004] For example, Figure 1 and Figure 2 As shown, in the traditional crucible structure, the temperature control thermocouple 8 of the heating module 13 is located at the bottom of the crystal growth crucible body 1. According to the temperature feedback of the temperature control thermocouple 8, the Eurometer controls the power change of the heating module 13 to keep the temperature at the temperature control thermocouple 8 stable. In the vertical gradient solidification crystal growth process (VGF), the furnace (the whole composed of the heating module 22, the heating module 13 and the heat dissipation zone 4) and the crystal growth crucible (the whole composed of the crystal growth crucible body 1, the support rod 5 and the ceramic rod 7) are both stationary, and the single crystal growth is achieved by the temperature change of the heating module 22; in the vertical Bridgman crystal growth process (VB), the temperature field remains unchanged, and the furnace or the crystal growth crucible is moved. In the process of moving the furnace or the crystal growth crucible, the temperature control thermocouple 8 and the crystal growth crucible body 1 remain relatively stationary but are not in contact with the heating module The position of the heating module -3 moves, and the bottom temperature of the crystal growth crucible controlled by the temperature-controlling thermocouple 8 remains constant (i.e., the connection point of the temperature-controlling thermocouple 8). However, during the movement, the temperature-controlling thermocouple 8 at the Cd source 6 is relatively located at different positions of the heating module -3. The temperature at the connection point of the temperature-controlling thermocouple 8 is stable, but the liquid surface temperature of the Cd source 6 changes, breaking the relative balance between the liquid surface temperature of the Cd source 6 and the melt. The high temperature causes Cd to enter the melt, and the low temperature causes the melt to release Cd outward. The change in temperature at the Cd source 6 causes differences in the control of inclusions.

[0005] Secondly, the test data show that: when the temperature of the temperature-controlling thermocouple 8 is kept unchanged, the liquid surface temperature of the Cd source 6 presents a parabolic change of first decreasing and then increasing during the process of the temperature-controlling thermocouple 8 moving from the upper position to the bottom position of the heating module 3. The change in the temperature of the Cd source 6 is manifested in the appearance of abnormal inclusions in certain areas of the ingot.

[0006] In addition, during the crystal growth process, the ceramic rod 7 that fixes the temperature-control thermocouple 8 is tilted to a certain extent, resulting in abnormal liquid surface temperature of the Cd source 6, failure of control of the Cd source 6, and abnormal inclusions. Summary of the invention

[0007] The technical problem to be solved by the utility model is to provide a crystal growth crucible for accurately controlling the temperature of a Cd source in view of the deficiencies in the prior art. The utility model can accurately control the temperature of the Cd source liquid surface, avoid differences between different devices or different positions of the same device, and is fully controllable in terms of repeatability, thereby achieving accurate control of cadmium zinc telluride inclusions.

[0008] The present solution is achieved through the following technical measures: a crystal growth crucible for accurately controlling the temperature of a Cd source, comprising a crystal growth crucible body, the bottom of the crystal growth crucible body being a concave structure, the concave structure forming a accommodating cavity one at the bottom of the inner cavity of the crystal growth crucible body, the accommodating cavity one being located on both sides of the concave structure, the accommodating cavity one being filled with a Cd source.

[0009] Preferably, the concave structure forms a second accommodating cavity at the outer bottom of the crystal growth crucible body, and the upper end of the temperature control rod extends into the second accommodating cavity.

[0010] Preferably, the liquid levels of the Cd sources in the two accommodating chambers on both sides of the concave structure are equal.

[0011] Preferably, the top of the temperature control rod is substantially flush with the liquid surface of the Cd source.

[0012] Preferably, a gap is left between the upper end of the temperature control rod and the side wall of the second accommodating chamber.

[0013] Preferably, the temperature control rod comprises a ceramic rod and a temperature control thermocouple, the temperature control thermocouple penetrates the ceramic rod, and the upper end of the temperature control thermocouple extends out of the upper end of the ceramic rod.

[0014] Preferably, a heating module is provided on the outer side of the crystal growth crucible body.

[0015] Preferably, the heating module comprises a heating module 1 and a heating module 2, and a heat dissipation area is arranged between opposite ends of the heating module 1 and the heating module 2.

[0016] Preferably, a stopper is installed at the upper end of the crystal growth crucible body.

[0017] Beneficial effects of the utility model:

[0018] 1. The design of the concave structure at the Cd source in the utility model avoids the difference between different devices or different positions of the same device, and achieves accurate control of the Cd source liquid surface temperature between different devices or different positions of the same device, avoiding the difference between different devices or different positions of the same device, and the repeatability is fully controllable, realizing the precise control of cadmium zinc telluride inclusions;

[0019] 2. The design of the concave structure at the Cd source in the utility model enables the upper end of the temperature control rod to be located inside the crystal growth crucible, thereby avoiding the temperature abnormality at the Cd source caused by the temperature control rod tilting and leaving the Cd source position during the growth process, thereby avoiding the existence of Cd source temperature instability.

[0020] It can be seen that compared with the prior art, the utility model has substantial characteristics and progress, and the beneficial effects of its implementation are also obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of a crystal growth crucible in the prior art.

[0022] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0023] Figure 3 It is a structural schematic diagram of the medium crystal growth crucible of the utility model.

[0024] Figure 4 for Figure 3 Enlarged view of point B.

[0025] In the figure, 1-crystal growth crucible body, 2-heating module 2, 3-heating module 1, 4-heating area, 5-support rod, 6-Cd source, 7-ceramic rod, 8-temperature-controlled thermocouple, 9-plug, 10-temperature-controlling rod, 11-accommodating chamber 1, 12-accommodating chamber 2, 13-concave structure. DETAILED DESCRIPTION

[0026] In order to clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods and in conjunction with the accompanying drawings.

[0027] A crystal growth crucible for precisely controlling the temperature of a Cd source comprises a crystal growth crucible body 1, a plug 9 is installed at the upper end of the crystal growth crucible body 1, the bottom of the crystal growth crucible body 1 is a concave structure 13, the concave structure 13 forms a receiving cavity 11 located on both sides of the concave structure 13 at the bottom of the inner cavity of the crystal growth crucible body 1, the receiving cavity 11 is filled with a Cd source 6, and the liquid levels of the Cd source 6 in the two receiving cavities 11 located on both sides of the concave structure 13 are equal. After the crystal growth crucible body 1 adopts the above-mentioned concave structure, the liquid level temperature of the Cd source 6 can be kept stable in the VB or VGF crystal growth process, avoiding the difference between different equipment or different positions of the same equipment (liquid level temperature of the Cd source 6), and realizing precise control of cadmium zinc telluride inclusions.

[0028] The concave structure 13 forms a second accommodating chamber 12 at the outer bottom of the crystal growth crucible body 1, and the upper end of the temperature control rod 10 extends into the second accommodating chamber 12. The top of the temperature control rod 10 is substantially flush with the liquid surface of the Cd source 6, and a gap is left between the upper end of the temperature control rod 10 and the side wall of the second accommodating chamber 12. After adopting this structural form, the upper end of the temperature control rod 10 is located inside the crystal growth crucible, avoiding the situation where the temperature of the Cd source 6 is abnormal due to the tilt of the temperature control rod 10. The temperature control rod 10 includes a ceramic rod 7 and a temperature control thermocouple 8, and the temperature control thermocouple 8 passes through the ceramic rod 7, and the upper end of the temperature control thermocouple 8 extends out of the upper end of the ceramic rod 7.

[0029] A heating module is arranged outside the crystal growth crucible body 1. The heating module comprises a heating module 1 3 and a heating module 2 2. A heat dissipation area 4 is arranged between the opposite ends of the heating module 1 3 and the heating module 2 2.

[0030] In the present invention, the Eurotherm meter controls the operation of the heating module 3 through the temperature feedback of the temperature-controlling thermocouple 8, so that the temperature at the vertex of the temperature-controlling thermocouple 8 (i.e., the liquid level position of the Cd source 6) remains stable. The temperature controlled by the temperature-controlling thermocouple 8 is Figure 4 The temperature at point P in the middle, that is, keep the temperature of point P stable. If the temperature of point P is lower than the set value, the Eurotherm meter controls heating module 3 to heat up. If the temperature of point P is lower than the set value, the Eurotherm meter controls heating module 3 to cool down.

[0031] The technical features not described in the present invention can be realized by existing technologies and will not be described here. The present invention is not limited to the above specific implementation methods, and changes, modifications, additions or substitutions made by ordinary technicians in the field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A crystal growth crucible for accurately controlling the temperature of a Cd source, comprising a crystal growth crucible body, characterized in that: The bottom of the crystal growth crucible body is a concave structure, and the concave structure enables the bottom of the inner cavity of the crystal growth crucible body to form a first accommodating cavity located on both sides of the concave structure, and the first accommodating cavity is filled with a Cd source.

2. The crystal growth crucible for accurately controlling the temperature of the Cd source according to claim 1, characterized in that: The concave structure forms a second accommodating cavity at the outer bottom of the crystal growth crucible body, and the upper end of the temperature control rod extends into the second accommodating cavity.

3. The crystal growth crucible for accurately controlling the temperature of the Cd source according to claim 2, characterized in that: The liquid levels of the Cd sources in the two accommodating chambers on both sides of the concave structure are equal.

4. The crystal growth crucible for accurately controlling the temperature of the Cd source according to claim 3, characterized in that: The top of the temperature control rod is substantially flush with the liquid surface of the Cd source.

5. The crystal growth crucible for accurately controlling the temperature of the Cd source according to claim 4, characterized in that: A gap is left between the upper end of the temperature control rod and the side wall of the second accommodating chamber.

6. The crystal growth crucible for accurately controlling the temperature of the Cd source according to claim 5, characterized in that: The temperature control rod comprises a ceramic rod and a temperature control thermocouple, the temperature control thermocouple penetrates the ceramic rod, and the upper end of the temperature control thermocouple extends out of the upper end of the ceramic rod.

7. The crystal growth crucible for accurately controlling the temperature of the Cd source according to claim 6, characterized in that: A heating module is arranged on the outer side of the crystal growth crucible body.

8. The crystal growth crucible for accurately controlling the temperature of the Cd source according to claim 7, characterized in that: The heating module comprises a heating module 1 and a heating module 2, and a heat dissipation area is arranged between opposite ends of the heating module 1 and the heating module 2.

9. The crystal growth crucible for accurately controlling the temperature of a Cd source according to any one of claims 1 to 8, characterized in that: A stopper is installed on the upper end of the crystal growth crucible body.

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