Integrated pouring type heating body with stable indium phosphide single crystal thermal field

Abstract

The utility model discloses an integrated pouring type heating body with a stable indium phosphide single crystal thermal field, and relates to a semiconductor material. The heating furnace comprises a heat preservation wall, heating furnace wires and porcelain heads, the heat preservation wall is cylindrical, the heating furnace wires are horizontally embedded in the inner wall of the heat preservation wall, the porcelain heads are arranged at the ends of the heating furnace wires, and thermocouple fixing holes are designed in the porcelain heads. The heating body is formed by integrally pouring zirconium-containing ceramic fiber cotton in a wet vacuum manner, naturally curing and then drying, and in the repeated high-low temperature recycling process, the shrinkage rate is extremely low, obvious size shrinkage does not exist, and the problem of sand leakage of heat preservation sand is solved; a high-temperature-resistant porcelain head is preset on the heating body corresponding to the temperature area, and a thermocouple fixing hole is reserved in the porcelain head to fix the position of a thermocouple; the thermal insulation layer is less in attenuation, free of sand leakage and consistent in thermal insulation property; the temperature measuring thermocouple is fixed, temperature measuring data are accurate, consistency and stability of different heating bodies and single crystal rate furnace thermal fields can be achieved, and the temperature deviation of the same position between different rounds is smaller than or equal to 3.

Description

Technical Field

[0001] The utility model relates to semiconductor materials, in particular to an integrated cast heating element with a stable thermal field of an indium phosphide single crystal. Background Art

[0002] Indium phosphide (InP) is an important III-V compound semiconductor material with excellent properties such as high electron mobility, high photoelectric conversion efficiency, high electron drift velocity, strong radiation resistance and good thermal conductivity. It is widely used in integrated circuits, solar cells, sensors and optical module devices, especially in fiber optic communications, millimeter wave and wireless applications.

[0003] Currently, the main methods for growing InP single crystals include the Liquid Encapsulated Czochralski (LEC), Vertical Bridgeman (VB), and Vertical Gradient Freeze (VGF). VB and VGF are the most widely used in industrial production. The InP single crystal growth process is essentially a temperature-controlled phase transition. First, the InP polycrystal is heated to melt, transforming from a solid phase to a liquid phase. The temperature is then lowered to solidify into an InP single crystal, transforming from a liquid phase to a solid phase. A stable thermal field during InP single crystal growth is a crucial prerequisite.

[0004] At present, the thermal field fluctuation of the indium phosphide single crystal furnace is comprehensively affected by the heating element, furnace tube, furnace core, insulation sand, etc. Among them, by controlling the technical parameters of the furnace tube, furnace core, and insulation sand, the fluctuation influence of the three is within the controllable range; the significant influencing factor of the fluctuation of the thermal field of the indium phosphide single crystal comes from the defects of the insulation layer and insulation structure of the heating element, which causes shrinkage deformation, and then causes changes in the filling amount and distribution differences of the insulation sand. The existing heating element insulation layer is mainly composed of a multi-layer filling and coating molding consisting of an inner layer of wet felt, a middle layer of zirconium-containing fiber felt, and an outer layer of zirconium-containing fiber felt. In the continuous cycle of high-temperature growth of indium phosphide single crystals and cooling to room temperature, the inner layer of wet felt and the middle layer of zirconium-containing fiber felt are non-uniform materials. There are differences in their material composition, bulk density, and water content. Due to thermal expansion and contraction, they shrink and deform, forming gaps, and insulating sand leaks from the gaps. Although the thermal fields of different single crystal growth rounds of the same heating element are greatly different, the differences between different heating elements are even more obvious. The difference in thermal field brings adverse effects on stable temperature control in production; at the same time, due to the shrinkage of the insulation layer, the position of the temperature measuring thermocouple moves, and the temperature measurement data of the thermocouple also changes due to the movement of the temperature measurement position, and the temperature measurement data loses its reference value.

[0005] In summary, the defects of the existing heating element insulation technology and insulation layer structure cause the insulation layer to attenuate and leak sand, resulting in insulation fluctuations, and the insulation layer shrinkage leads to distortion of temperature measurement data, which in turn leads to fluctuations in the thermal field of indium phosphide single crystal growth. Production mainly relies on experienced temperature control engineers to manually judge and compensate for temperature. The qualified rate of indium phosphide single crystals is affected by artificial temperature control, which has become an important problem restricting the stable growth of indium phosphide single crystals. Summary of the Invention

[0006] The utility model aims to solve the defects of the existing heat preservation technology and heat preservation layer structure of the heating element, and provides an integral cast heating element with a stable heat field of the indium phosphide single crystal.

[0007] The utility model is an integrated cast heating element with a stable indium phosphide single crystal thermal field, characterized in that the heating element comprises an insulation wall, a heating furnace wire and a porcelain head, the insulation wall is cylindrical, a plurality of heating furnace wires are horizontally embedded on the inner wall of the insulation wall, a porcelain head is provided at the end of the heating furnace wire, and a thermocouple fixing hole is designed on the porcelain head.

[0008] The thermal insulation wall comprises zirconium-containing ceramic fiber wool and composite high-temperature cement. The thermal insulation density of the zirconium-containing ceramic fiber wool is ≥300kg / m³. The zirconium-containing ceramic fiber wool is crushed and evenly mixed with the composite high-temperature cement before being cast into an integral shape.

[0009] The several heating wires are divided into several sections from top to bottom, each section is a temperature control zone, each temperature control zone is temperature controlled separately, a thermocouple is installed in each temperature control zone, and the thermocouple is installed in the thermocouple fixing hole of the porcelain head at the corresponding position to improve the temperature control accuracy.

[0010] The application process steps of this heating element are:

[0011] (1) Insert the thermocouples into the holes of the porcelain heads and fix the thermocouples;

[0012] (2) Assembling the heating element into an indium phosphide single crystal furnace and completing wiring;

[0013] (3) Assembling furnace tubes;

[0014] (4) Fill the gap between the furnace tube and the heating element with insulating sand.

[0015] Compared with the existing technology, this heating element has the following beneficial effects:

[0016] (1) The heating element is made of zirconium-containing ceramic fiber cotton wet vacuum casting, natural curing and then drying. It is an integrated ring structure. During repeated high and low temperature cycles, the shrinkage rate is extremely low and there is no obvious dimensional shrinkage, which solves the problem of sand leakage in thermal insulation sand.

[0017] (2) The heating element is preset with a high-temperature resistant ceramic head in the corresponding temperature zone, and the ceramic head is designed with a thermocouple fixing hole to fix the position of the thermocouple;

[0018] (3) The insulation layer has less attenuation, no sand leakage, and consistent thermal insulation; the temperature measuring thermocouple is fixed, the temperature measurement data is accurate, and the consistency and stability of the thermal field of different heating elements and single crystal furnaces can be achieved, and the temperature deviation at the same position between different rounds can be ≤3%;

[0019] (4) The technical advantages of fixed thermocouple position and stable thermal conductivity can be achieved, and the temperature deviation at the same position between different rounds can be ≤0.3%, which effectively solves the problems of unstable thermal field and fluctuation of single crystal yield in the existing indium phosphide single crystal growth process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the cross-sectional structure of the utility model.

[0021] Among them, there are insulation wall 1, heating wire 2, and porcelain head 3. DETAILED DESCRIPTION

[0022] Example 1: An integral cast heating element with a stable indium phosphide single crystal thermal field, comprising an insulation wall, a heating furnace wire and a porcelain head. The insulation wall is cylindrical, and several heating furnace wires are horizontally embedded on the inner wall of the insulation wall. A porcelain head is provided at the end of the heating furnace wire, and a thermocouple fixing hole is designed on the porcelain head. The insulation wall contains zirconium-containing ceramic fiber wool and composite high-temperature cement. The zirconium-containing ceramic fiber wool is crushed and evenly mixed with the composite high-temperature cement and then cast into an integral shape. The composite high-temperature cement adopts the commercially available coating cement of Wuhan Dashan Thermal Ceramics Co., Ltd., and the product model is 634-AS-LV200CPS. Several heating furnace wires are divided into several sections from top to bottom, each section is a temperature control zone, and each temperature control zone is temperature-controlled separately. A thermocouple is installed in each temperature control zone, and the thermocouple is installed in the thermocouple fixing hole of the porcelain head at the corresponding position to improve the temperature control accuracy. The thermal insulation density of zirconium-containing ceramic fiber wool is preferably 350kg / m³-480kg / m³.

Claims

1. An integral cast heating element with a stable thermal field of indium phosphide single crystal, characterized in that The heating element includes an insulation wall, heating furnace wires and a porcelain head. The insulation wall is cylindrical, and several heating furnace wires are horizontally embedded on the inner wall of the insulation wall. A porcelain head is provided at the end of the heating furnace wire, and a thermocouple fixing hole is designed on the porcelain head.

2. The integral cast heating element with a stable thermal field of indium phosphide single crystal according to claim 1, characterized in that The thermal insulation wall comprises zirconium-containing ceramic fiber wool and composite high-temperature cement. The thermal insulation density of the zirconium-containing ceramic fiber wool is ≥300kg / m³. The zirconium-containing ceramic fiber wool is crushed and evenly mixed with the composite high-temperature cement before being cast into an integral shape.

3. The integral cast heating element with a stable thermal field of indium phosphide single crystal according to claim 1, characterized in that The heating wires are divided into several sections from top to bottom, each section is a temperature control zone, each temperature control zone is temperature controlled separately, a thermocouple is installed in each temperature control zone, and the thermocouple is installed in the thermocouple fixing hole of the porcelain head at the corresponding position.

Images