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CN-121976289-A - Crystal growth apparatus and method

CN121976289ACN 121976289 ACN121976289 ACN 121976289ACN-121976289-A

Abstract

A crystal growth device and method are provided, wherein a temperature measuring hole is formed in the center of the top of a heat preservation chamber, a crucible system is arranged in the heat preservation chamber, the crucible system comprises a crucible, an external auxiliary heat preservation cylinder is fixedly sleeved on the outer side of the upper end of the heat preservation chamber, and the upper end of the external auxiliary heat preservation cylinder is located above the upper end of the heat preservation chamber. In the crystal growth process, a vertical outer airflow circulation channel is formed through an outer auxiliary heat preservation cylinder, a vertical middle airflow circulation channel is formed through a middle auxiliary heat preservation cylinder, a vertical inner airflow circulation channel is formed through an inner auxiliary heat preservation component, and by means of the directional flow characteristic of gas phase, gas phase components escaping from a crucible system in the growth process are guided to be discharged out of a heat preservation chamber or deposited in the airflow circulation channel along the outer airflow circulation channel, the middle airflow circulation channel and the inner airflow circulation channel in a directional manner. The device and the method can effectively improve the accuracy of the temperature measurement result, can effectively reduce the corrosion rate to the heat preservation chamber, can ensure better controllability of the crystal growth process, and are beneficial to improving the repeatability between furnace times.

Inventors

  • LI YUANTIAN
  • HAN QIAN
  • YIN LIANGLIANG
  • WU ANNAN
  • HU JIALE

Assignees

  • 江苏集芯先进材料有限公司

Dates

Publication Date
20260505
Application Date
20260224

Claims (10)

  1. 1. A crystal growth apparatus, comprising: The temperature-measuring device comprises a temperature-preserving chamber (1), wherein a temperature-measuring hole (2) is formed in the center of the top of the temperature-preserving chamber (1); A crucible system (5), wherein the crucible system (5) is arranged in the heat preservation chamber (1), and the crucible system (5) comprises a crucible (3); The outer heat preservation section of thick bamboo (4) of assisting, outer heat preservation section of thick bamboo (4) of assisting is fixed the suit in the outside of heat preservation room (1) upper end, and its upper end is located the top of heat preservation room (1) upper end.
  2. 2. The crystal growth apparatus of claim 1, wherein the outer side of the upper end of the heat preservation chamber (1) is provided with an upper outer annular step (27), and the outer auxiliary heat preservation cylinder (4) is fixedly sleeved on the outer side of the upper outer annular step (27).
  3. 3. A crystal growth apparatus according to claim 1, further comprising: The inner auxiliary heat preservation assembly (6), the inner auxiliary heat preservation assembly (6) is of a cylindrical structure and is fixedly inserted into the temperature measuring hole (2), the upper end of the inner auxiliary heat preservation assembly is located above the upper end of the heat preservation chamber (1), the inner auxiliary heat preservation assembly (6) comprises a graphite cylinder (7) and an inner auxiliary heat preservation cylinder (8), and the inner auxiliary heat preservation cylinder (8) is fixedly sleeved on the outer side of the graphite cylinder (7).
  4. 4. The crystal growth device according to any one of claims 1 to 3, further comprising a middle auxiliary heat preservation cylinder (9), wherein the heat preservation chamber (1) comprises a main heat preservation cylinder (10) and a heat preservation cover plate (11), the upper end of the main heat preservation cylinder (10) is opened, an upper inner annular step (12) is arranged on the inner side of the upper end of the main heat preservation cylinder, the heat preservation cover plate (11) is covered at the upper inner annular step (12), an annular installation space is formed between the heat preservation cover plate (11) and the upper end of the main heat preservation cylinder (10), and the temperature measuring hole (2) is formed in the heat preservation cover plate (11); the middle and auxiliary heat preservation cylinder (9) is inserted in the annular installation space.
  5. 5. A crystal growth apparatus according to claim 4, further comprising a cushion layer (15), the cushion layer (15) being disposed between the heat insulating cover plate (11) and the upper inner annular step (12).
  6. 6. The crystal growth apparatus according to claim 5, wherein an annular concave table (28) is provided on the outer side of the lower end of the heat-insulating cover plate (11), the height of the annular concave table (28) is the same as the thickness of the cushion layer (15), and the lower end of the heat-insulating cover plate (11) is lapped on the cushion layer (15) through the annular concave table (28).
  7. 7. A crystal growth apparatus according to claim 1, wherein the outer auxiliary insulating cylinder (4) is made of graphite soft felt.
  8. 8. A crystal growth apparatus according to claim 3, wherein the inner auxiliary insulating cylinder (8) is made of graphite felt.
  9. 9. A crystal growth apparatus according to claim 5, wherein the secondary insulating cylinder (9) is made of graphite soft felt, and the cushion layer (15) is made of graphite soft felt.
  10. 10. A crystal growth method using a crystal growth apparatus according to claim 6, comprising the steps of: In the crystal growth process, a vertical outer airflow circulation channel is formed through an outer auxiliary heat preservation cylinder (4), a vertical middle airflow circulation channel is formed through a middle auxiliary heat preservation cylinder (9), a vertical inner airflow circulation channel is formed through an inner auxiliary heat preservation assembly (6), and by means of the directional flow characteristic of gas phase, gas phase components escaping from a crucible system (5) in the growth process are guided to be directionally discharged out of the heat preservation chamber (1) along the outer airflow circulation channel, the middle airflow circulation channel and the inner airflow circulation channel or deposited in the airflow circulation channel.

Description

Crystal growth apparatus and method Technical Field The invention belongs to the technical field of semiconductors, and particularly relates to a crystal growth device and a crystal growth method. Background Currently, when a physical vapor transport method (Physical Vapor Transport, PVT method) is adopted to grow silicon carbide (SiC) crystals, the whole temperature regulation is generally realized by monitoring the temperature at the top of a thermal field. The core principle of PVT method growth is that by constructing a significant temperature difference between the top seed crystal and the bottom powder, a temperature gradient required by crystal growth and physical substance transportation is formed, so that SiC crystal growth is driven. The monitoring of the crystal growth temperature (namely the temperature of the position of the top seed crystal) is mainly realized by temperature measuring equipment such as an infrared thermometer, and the infrared thermometer is used as a non-contact type temperature measuring instrument, and the working principle of the non-contact type temperature measuring instrument is that a balance comparison method is adopted to detect the radiant energy of a measured object, and the radiant energy signal is converted into a corresponding temperature value, so that the non-contact type temperature measurement is realized. However, during the growth of SiC crystals, an extremely high temperature environment is maintained within the reaction chamber, wherein the temperature required to stably grow a single crystal form of 4H-SiC is above 2100 ℃. Under the high-temperature growth scene, particularly when a large axial temperature gradient exists in a thermal field, irregular movement of gaseous substances (Si mCn) generated after powder sublimation can occur, and the process can cause significant interference to the temperature monitoring in the whole growth process of the silicon carbide crystal. Although the measured value of the infrared thermometer only reflects the relative temperature of the region to be measured, the infrared thermometer has irreplaceable important significance for stable monitoring and accurate regulation of high temperature above 2100 ℃ in the silicon carbide crystal growth process. In addition, the silicon carbide crystal growth process has the characteristics of high temperature, long growth period, large bottom volatile migration from bottom to top and the like, and the factors cause the problems that a temperature measurement window and a temperature measurement channel are extremely easy to be polluted and interfered by volatile substances, so that unstable temperature measurement and even temperature measurement failure are caused. Once the temperature monitoring fails, the silicon carbide crystal growth process is in a blind state which cannot be controlled in real time, a worker cannot timely sense the temperature variation in the growth process, and cannot pertinently make process adjustment, so that the crystal growth failure or the substandard crystal quality can be finally caused. Meanwhile, silicon carbide consists of two elements of carbon (C) and silicon (Si), and the difference of key physical parameters such as melting points of the carbon and the silicon is remarkable. With the rise of the growth temperature of the silicon carbide crystal and the extension of the growth time, the silicon carbide powder at the bottom can generate a silicon-rich gas phase component after being heated and decomposed in the middle and early stages of growth, and the part of the silicon-rich gas phase component which does not participate in the crystal growth and escapes from a crucible or a thermal field can chemically react with graphite felt (carbon felt) in the thermal field in the upper half area of the thermal field with relatively low temperature and form crystals after being volatilized upwards. On one hand, the crystallization product can further shield a temperature measuring channel and interfere with a temperature measuring signal to reduce the accuracy of temperature measurement, and on the other hand, the crystallization product can cause serious corrosion to a thermal field structure. Along with repeated multiplexing of the thermal field, severe corrosion of the areas, such as the top of the thermal field, which are easy to react with escaping gas phase components can be obviously observed. The corrosion loss of the thermal field not only can reduce the reuse times and increase the production cost, but also can obviously influence the core performance (especially the heat preservation performance) of the upper half part of the thermal field, so that the growth process parameters among different heat levels have larger fluctuation, and further the consistency and the stability of the growth of the silicon carbide crystal are influenced. Aiming at the technical pain points of insufficient temperature measurement accuracy, temperature measurem