With the development of solid-state technology industrialization, solid-state thin films are more widely used in high-tech fields
Circuit manufacturing, magnetic recording materials and devices, solid light emitting materials and flat panel display devices
Thin film manufacturing technology. Thin film manufacturing technology is diverse, of which one is the most common and widely used thin film
The film manufacturing technology is a vacuum evaporation technology. Its main applications include various packaging materials, capacitor manufacturing and imaging
Tubes, high-precision flat panel display technology, superlattice quantum trap materials, etc., have a huge market capacity. In vacuum
In the evaporation technology, the evaporation source is the key to affect the film quality and manufacturing cost. In general, metal evaporation line
The industry has put forward many requirements for evaporation source boat materials: suitable resistivity range and resistance temperature system
Number; Excellent heat shock resistance; Excellent corrosion resistance to molten metal; Good wetting with molten metal at high temperature
Sex; Easy machinability, sufficient strength, etc.
In the early metal evaporation industry, the evaporation material used for evaporation of metals (such as aluminum) was carbon stone
Ink material. This evaporation source boat material has some difficult problems in the use process, such as poor quality
Stable, low service life. The main reason is that for most metals, carbon. Graphite evaporation
The boat can react with many metals at high temperatures to form carbides, causing flowering, blistering and complete destruction
This has affected the service life of the evaporation boat. In order to prevent the reaction between carbon and metal and improve the use performance of crucibles, domestic and foreign
Researchers have done a lot of work.
In 1994, Huang Jianhua [17] studied the carbon graphite material evaporation boat with respect to the relevant characteristics of graphite materials and the coating process
This paper summarizes and discusses the main technical requirements of and the problems existing in the operation of users at that time
Amorphous carbon with high purity, large specific gravity, low porosity and good conductivity is selected as the base material
The carbon graphite evaporation boat with good performance and long service life was prepared with proper ratio.

In 1996, Wang Minghua [I 8] developed the method of impregnating aluminum nitrate to improve graphite steaming through a series of experiments
New technology for improving the service life of launch boats. The basic principle is to press the filler into the air hole by vacuum pressurization and other methods
Since aluminum nitrate is easily soluble in water, after immersion, the aluminum nitrate remaining in the pores of the product is heated,
The alumina produced by the decomposition reaction fills the pores of the crucible, hindering the reaction between the molten aluminum and carbon, thus prolonging the
Service life of graphite evaporation boat. The test results show that the service life of graphite evaporation boat can be improved after treatment with this method
Life increased by about 30%.
In 1996, in order to improve the corrosion resistance of graphite crucibles to molten aluminum, foreign researchers [19] vapor deposited molten gold
Graphite crucible with long service life for vapor deposition was prepared by modifying the surface of graphite crucible
Pot. The crucible is characterized by forming a silicon carbide film on part or the whole surface of the crucible surface, and then
A layer of silicon carbide film is deposited and coated on the surface of the silicon carbide, thus forming a double-layer structure
Silicon carbide. Wherein the silicon carbide formed is mainly composed of B-type silicon carbide. At 1450 ℃,
1 o-5toit under vacuum. After melting the metal aluminum and repeating the evaporation operation for 2 hours, it was found that no
The service life of the carbon crucible for metal evaporation after forming B-type silicon carbide is 42 times
The lifetime of the CVD crucible is 70 and 75 times, while the lifetime of the crucible with a double-layer structure is 90 times. can
It can be seen that its corrosion resistance to molten aluminum has been greatly improved.
Because graphite crucible is easy to be oxidized, many people have modified it. In 1999, Chen Jian [2 prefectures in
Add about 14% and 16% antioxidant additives (silicon powder, ferrosilicon powder, glass
The antioxidant activity was increased by 43.7% and 79%. In 2001, Xiao Yunfeng [21] et al
Heat resistant coatings were prepared by plasma spraying Nb, Mo, cazr03, Zr02 (V203) powders on the surface of graphite, and the properties of graphite were tested
The thermal shock stability of the ink coating was analyzed by X-ray diffraction and scanning electron microscopy. The results show that stone
Cazros (Y203) and Mo / Zr02 (Y203) composite coatings were found on the surface of ink by thermal shock at 1600 ℃
The adhesion strength of the layer is higher than the fracture strength of the graphite matrix, and the carbon blocking effect is obvious.
As an early evaporation boat material, graphite has many unsolvable problems in its use. as
Graphite can react with many metals at high temperatures to form carbides, especially when evaporating metal aluminum
The reaction produces aluminum carbide with volume expansion, which leads to cracking of the crucible and finally brittle fracture. Later generations
It was found that BN has good corrosion resistance to molten aluminum, minimal heat shock resistance, and easy machining,
The wetting angle of molten aluminum at high temperature decreases with the increase of temperature. So BN is an ideal boat material.
However, BN has high-temperature electrical insulation, if it is used as an evaporator, it must be added with a heat source. It's easy to think
To put a graphite container outside BN, but this double crucible system has a fatal disadvantage, when
When the system is heated to 1100, - 1700 ℃, the molten aluminum overflows from the BN crucible inside and joins the graphite outside
The crucible contact reaction generates aluminum carbide, which causes the outer crucible to burst and affects the service life.
Because boron nitride itself cannot conduct electricity, people turn their attention to a kind of material that can generate heat, conduct electricity and have high resistance
Warm corrosion composite materials. According to the requirements of the evaporation industry, various conductive ceramics are screened and tested
TiB2 in boride is the most promising conductive phase. TiB2 and BN were prepared into multiphase ceramics,

According to the additivity of the composite, the multiphase ceramics can maintain the common properties of the single-phase ceramics, so BN. TiB,

Multiphase ceramics can maintain their common excellent properties: good wettability to molten metal at high temperature, excellent
Corrosion resistance of molten metal and excellent heat resistance. TiB2 has conductivity comparable to that of metal, and
The resistivity range is 9-30uflcm, and BN is an excellent insulator. By controlling the ratio between the two
The composite conductive ceramics with the required resistivity can be obtained by the particle size ratio and the temperature system at the time of firing, and can be prepared into vapor deposition industry
According to different requirements, the resistivity of the evaporation boat in can be in the range of 100 ~ 1500uf! Cm or wider
Ask questions and choices. TiB2 and BN are used to prepare multiphase ceramics. Because of the existence of BN, its machinability is ten
Excellent quality, which is very important when processing into an evaporation boat. At the same time, bn.tib2 is polyphase due to the presence of BN
Conductive ceramics have excellent thermal shock resistance. The difference between the thermal expansion coefficients of the two is small, and in the rise of the evaporation boat
The thermal stress during cooling is small.
In 1999, Chen Shuquan et al. [23] added a certain amount of Si3N4 to bn.tib2-based conductive evaporation boat to study
The effect of Si3N4 on the electrical properties and corrosion resistance of the conductive evaporation boat was studied. It was found that adding an appropriate amount of Si3N4
It can form Simon material with A1203 and a in the material on the basis of ensuring good electrical performance
Tib2-a1n.bn composite. The corrosion damage of materials is caused by the erosion reaction of sampans to BN. Since Simon
The existence of the material effectively prevents the corrosion of BN particles by the molten aluminum, thus greatly improving the resistance of the evaporation boat
Aluminum corrosion ability, extended service life.