TWI628141B - 坩埚 release agent material - Google Patents

Abstract

The present invention provides a bismuth release agent material, which is mainly composed of tantalum nitride having a weight percentage of 0.5 to 30% and a particle size of less than 100 nm. In the present invention, the nanometer-sized tantalum nitride powder can be coated between a generally larger particle size tantalum nitride and a void which is filled in a generally larger particle size tantalum nitride stack, so that the crystal growth process In the middle, the nano-cerium nitride can produce micro-sintering and enhance the bonding force between the tantalum nitrides of the bismuth release agent, so as to solve the problem that the bismuth release agent in the prior art is peeled off or powdered during use, and is not added. The increase in the process and cost caused by the adhesive and the problem of pollution.

Description

坩埚 release agent material

The present invention provides a bismuth release agent material, and more particularly to a bismuth release agent material comprising a proportion of nano-sized cerium nitride particles.

With the development of green energy, polycrystalline germanium is the most widely used material on solar cells. In the preparation of polycrystalline germanium ingots, the raw material blocks of higher purity polycrystalline germanium are first placed in high temperature resistant quartz crucibles for melting, crystal growth, annealing and cooling. After that, the polycrystalline germanium ingot is taken out from the quartz crucible and the cutting operation is performed.

However, in the process of melting the polycrystalline germanium material block, the quartz crucible is in contact with each other for a long time, and the two will react with each other, and the impurities in the quartz crucible will also melt into the polycrystalline crucible, causing pollution, which not only leads to a decrease in the quality of the cast polycrystalline ingot, The viscous condition also occurs, and when cooling, the expansion coefficients of the polycrystalline bismuth ingot are increased due to the different expansion coefficients of the two, and the residual rupture chance is also relatively increased due to the residual stress. In order to solve such problems, tantalum nitride is generally coated on the inner surface of the quartz crucible as a barrier material to isolate the polycrystalline germanium material block from directly contacting the crucible surface during the melting process, thereby not only reducing the viscosity state but also reducing the chance of impurity contamination.

1 is a schematic view showing the combination and distribution of tantalum nitride particles coated with tantalum nitride on the inner surface of a quartz crucible without additional adhesive added in the prior art. The conventional tantalum nitride 11 coated on the inner surface of the crucible has a particle diameter D10. Generally it is between 0.7~1.5μm, D50 is generally between 1.0~3.5μm, D90 is generally between 3.5~6.5μm, when applied to quartz crucible internal table The surface is a natural stack of mechanical occlusion, physically adsorbed on the inner surface of the quartz crucible. If the coating is only mixed with tantalum nitride and water, the sintering temperature is still greater than the highest temperature during the growth of the crystal growth. In the crystal process, peeling or falling powder is prone to occur, which causes the tantalum melted soup to be contaminated by the tantalum nitride particles and affects the effect of blocking impurities. Therefore, in order to solve this problem, in the prior art, an organic or inorganic adhesive is added to increase the bonding strength between the tantalum nitride particles. However, the addition of an adhesive not only increases the cost and process time of the process, but at high temperatures, the adhesive releases oxygen atoms, causing oxygen to diffuse into the molten soup, causing pollution and affecting the quality of the polycrystalline ingot, so these problems It is still our urgent need to improve and solve.

In order to solve the above problems, the present invention provides a bismuth release agent material having a certain proportion of nano cerium nitride.

The ruthenium release agent material provided by the present invention is mainly composed of tantalum nitride having a weight percentage of 0.5 to 30% and a particle size of less than 100 nm.

The preferred particle size of the nanonitride lanthanum of the release agent material is between 10 and 50 nm.

The tantalum nitride accounts for 99% by weight of the release agent material.

The D50 of the tantalum nitride is between 1.0 and 3.5 μm, and the ratio of the β phase or the α phase is between 51 and 99%.

The invention provides a bismuth release agent material with a certain proportion of nanometer cerium nitride. The sintering temperature of the nano cerium nitride through the nano cerium nitride is lower than that of the generally larger cerium nitride and the nano cerium nitride can be coated in the general Large particle size tantalum nitride and filled with a generally larger particle size tantalum nitride stack The characteristics between the voids enable the nano-sintering of the nano-cerium nitride to increase the bonding force between the tantalum nitrides of the bismuth release agent during the crystal growth process, so as to solve the prior art hydrazine release agent during use. The problem of spalling or falling off is caused, and the increase in the number of processes and costs caused by the addition of the adhesive and the problem of contamination are eliminated.

11‧‧‧larger size tantalum nitride

12‧‧‧Nano-nitride

Fig. 1 is a schematic view showing a natural packing arrangement of general tantalum nitride.

Figure 2 is a photograph of the present invention taken at SEM.

Fig. 3 is a schematic view showing that nano-rhenium nitride is coated in a most densely packed manner to coat a general tantalum nitride.

Fig. 4 is a schematic view showing the filling of nanometer tantalum nitride in a general tantalum nitride.

Fig. 5 is a photograph taken after a scratch test of a conventional general tantalum nitride coating.

Figure 6 is a photograph taken after the scratch test of the nanoparticle-coated tantalum nitride coating of the present invention.

The specific embodiment of the release agent material of the present invention will be described below with reference to the drawings.

Please refer to FIG. 2 to FIG. 4 . FIG. 2 is a photograph taken by the SEM according to the present invention. It can be seen that the nano-rhenium nitride 12 is randomly filled and coated on the gap and surface between the generally larger particles of tantalum nitride 11 . Figure 3 is a schematic diagram of the nano-tantalum nitride 12 in the most densely packed arrangement, which is coated with a generally larger particle size of tantalum nitride 11; Figure 4 is a nano-tantalum nitride 12 filled in a generally larger particle size tantalum nitride 11 Schematic diagram. The release agent material of the present invention comprises 99% by weight or more of lanthanum nitride (Si ₃ N ₄ ) and other less than 1% by weight such as iron (Fe), calcium (Ca), nickel (Ni), copper (Cu), yttrium (Y) , titanium (T), chromium (Cr), tungsten (W) or manganese (Mn) and other substances, wherein the proportion of β in the tantalum nitride (Si ₃ N ₄ ) is between 51% and 99%, Others are one or both of the alpha phase or the gamma phase. In other embodiments, the ratio of the α phase of tantalum nitride (Si3N4) is between 51% and 99%, and the others are one or both of the β phase or the γ phase.

The cerium nitride particle size range of the bismuth release agent material provided by the invention is substantially normal distribution, and contains a certain proportion of nano cerium nitride particles, and the nano nitrogen is applied when the release agent is coated on the inner surface of the crucible. The bismuth-removing granules can be coated on the generally larger-sized cerium nitride particles, and can also be filled in the gap formed between the larger-sized cerium nitride particles, because the nano-sized cerium nitride particles have a lower sintering temperature. Therefore, when the crystal is grown, the sintering effect can be produced at the melting temperature of the raw material, and the sintering effect can be strengthened to strengthen the bonding force between the tantalum nitride particles in the coating to form a stable structure, thereby effectively preventing the coating from peeling off or falling off. In the case of powder, the contact between the enamel and the enamel soup can be effectively reduced and the viscous condition between the ingot and the ingot can be effectively improved, and the rupture of the polycrystalline bismuth ingot is well improved.

The release agent material of the present invention is mainly characterized in that the cerium nitride component has a certain proportion of nanometer cerium nitride particles having a particle diameter of less than 100 nm. In order to optimize the bonding force of the release agent coating, the present invention is calculated in the most densely packed arrangement, and the closest packed arrangement refers to the manner in which the most overlapping spheres are placed within a certain range. To achieve the best stacking effect, calculate the weight percentage range of nano-nitride, and verify the specific effect by experiment.

Since the number of nano-sized cerium nitride 11 coated with nano-cerium nitride 12 is larger than that of nano-sized cerium nitride 12 filled with larger particles of tantalum nitride 11, the densest packing is larger. The amount of barium nitride nitride is used as the basis for the maximum range, and the basis for filling the gap between the larger particles of tantalum nitride is the minimum range. Calculating the amount of nano-cerium nitride coating on the surface of the larger particle tantalum nitride is the ratio of the projected area of the nano-sized tantalum nitride 12 in the most densely packed manner to the surface area of the larger particle size of the tantalum nitride. equation , where N is the number of nano-cerium nitrides 12 required to coat the larger particles of tantalum nitride 11, R is the radius of the larger particles of tantalum nitride, r is the radius of the nano-cerium nitride, nanonitriding The content of cerium varies depending on the particle size of the larger particle cerium nitride coated. For example, a 50 nm nano-n-nitride is arranged in the closest packing, and a larger particle of cerium nitride having a D50 of 3 μm is completely coated. According to the above equation, the number of particles of N=14884 is determined. Then, by multiplying the volume and the density, the weight of the nanometer tantalum nitride can be obtained, and the maximum weight percentage is 6.45 wt%.

Generally, the sintering temperature of the powder is below the melting point temperature, about 0.9 times the melting point, and the general particle size of the tantalum nitride has a sintering temperature of more than 2073 K, which is higher than the highest temperature in the crystal growth process, so the nitrogen in the crystal growth process Huayu can not produce sintering. In the prior art, in order to strengthen the bonding force of the tantalum nitride coating, generally other additives are added, but this will increase the cost of the crystal growth process, increase the process, and increase the oxygen diffusion opportunity, thus the polycrystalline silicon. The quality of the ingot can have serious adverse effects. The invention utilizes the thermal properties of the nanometer size of nano-n-nitride 12 in the release agent material, and the sintering temperature of the nano-cerium nitride 12 is lower than the sintering temperature of the general-purpose tantalum nitride 11 according to the surface specific effect. About 300~400K, so the nano-melting layer 12 coated in the tantalum nitride release coating on the inner surface of the crucible during the crystal growth process will have a micro-melting state, and has a sintering effect, so that the tantalum nitride coating The bonding strength of the layer is significantly increased.

The body-to-body ratio effect causes the sintering temperature of tantalum nitride. At the nanometer size, the sintering temperature drops by 300-400K because the solid material changes optical, mechanical, thermal and electrical properties at the nanometer size, when the total volume is fixed. The smaller the particle size, the larger the total surface area and the larger the total surface area. The proportion of atoms exposed to the outer layer becomes larger, which causes the internal energy required for sintering and melting to become smaller, lowering the sintering temperature and melting point, and when the tantalum nitride is less than 100 nm in nanometer size, the surface specific effect has a sintering temperature. Obvious influence. The effect of different materials will also be different. For example, if the particle size of gold particles is 10 nm, the melting point will decrease by about 27K, and 2nm will decrease by about 300K.

According to the literature [Semicond. Sci. Technol. 16 (2001) L33-L35], a simulation formula for the influence of nanoparticle on the melting point is obtained: r and r0 are the particle diameters, Tr and T0 are the melting points of the particle diameters r and r0, respectively, and σr and σ0 are the mean square displacement of the particle size r and the mean square displacement of r0, respectively, and α is the particle surface. The ratio of the square displacement to the internal mean square displacement. According to the above formula, when the temperature reaches 1773K, the sintering effect is obtained when the tantalum nitride particles are less than 100 nm, and the sintering effect is less obvious when the temperature is above 100 nm.

The invention adopts the most dense packing arrangement, generally the gap between the tantalum nitride and the tantalum nitride 11 is large, and the voids are minimized due to the filling of the nanometer tantalum nitride 12, and the sintering temperature of the nanometer tantalum nitride 12 Reduced, so when the temperature reaches 1673 ~ 1773K, the sintering effect can be achieved, which will promote the formation of a more stable barrier layer and strengthen the adhesion strength between tantalum nitride and tantalum nitride. Therefore, it is no longer necessary to use additives. In order to achieve the strengthening of the bonding strength of tantalum nitride, this not only reduces the chance of bismuth nitride flaking or falling powder, but also avoids the rutting caused by the reaction with bismuth melt in the process of crystal growth, which greatly reduces the cause. Adhesive is added, which causes contamination of oxygen diffusion.

The preferred weight percentage of nano-cerium nitride contained in the present invention is described below in the detailed description.

When the average particle diameter of the nanometer niobium nitride is 90 nm, and the tantalum nitride having a D50 of 1 μm is coated in the closest packing manner, the weight percentage of the nanometer niobium nitride can be calculated to be about 30%.

When the average particle diameter of the nanometer niobium nitride is 50 nm, and the tantalum nitride having a D50 of 1 μm is coated in the closest packing manner, the weight percentage of the nanometer niobium nitride can be calculated to be about 18%.

When the average particle diameter of the nanometer tantalum nitride is 10 nm, and the tantalum nitride having a D50 of 3.5 μm is coated in the closest packing manner, the weight percentage of the nanometer tantalum nitride can be calculated to be about 0.5%.

The weight percentage of nano-cerium nitride will vary proportionally with the relationship between the average particle diameter of nano-cerium nitride and the particle size of the general tantalum nitride coated, but it is not easy to be nitrided by nano-nitride. Production, when the proportion of nano-nitride is higher, the cost will increase. Therefore, the ideal particle size range of nano-cerium nitride is between 10 and 50 nm, which accounts for nitriding in the release agent material. The preferred range of weight percentage is between 1 and 20% by weight.

Figure 5 is a release agent material containing general tantalum nitride, which is applied to the coating after the crystallization of the ruthenium. After scraping, it can be seen that it is still in a powdery structure; Figure 6 shows that the invention has certain The ratio of the nano-tantalum nitride release agent material is coated on the coating after the crystallization process of the ruthenium, and after scraping, a sheet-like structure is formed, indicating that the release agent having nano-rhenium nitride is After the crystal growth process, the sintering effect is indeed produced, and the bonding strength of the tantalum nitride coating is remarkably enhanced.

The invention effectively strengthens the bonding strength between the tantalum nitrides by the characteristics of the tantalum nitride in the nanometer size, and can significantly reduce the sticking of the ingot and the crucible compared with the prior art, and avoid the flaw of the crucible caused by the sticking. Reducing the stress defects caused by sticking in the ingot, reducing the process cost, reducing the number of processes, reducing the oxygen diffusion rate in the crystal growth process, and greatly increasing the yield of the ingot by eliminating the need for an adhesive. The above is only a preferred embodiment for explaining the present invention, and is not intended to limit the invention in any way. Any modifications or alterations to the present invention in the spirit of the same invention should still be included. It is intended to be within the scope of the invention.

Claims (5)

A bismuth release agent material mainly composed of tantalum nitride, characterized in that: the D50 of the tantalum nitride is between 1.0 and 3.5 μm, and the weight percentage of the tantalum nitride component is between 0.5 and 0.5 30%, nanometer tantalum nitride having a particle diameter of less than 100 nm, and the nanometer tantalum nitride particles having a particle diameter of less than 100 nm may be filled in the gap between the larger tantalum nitride particles and coated on the larger tantalum nitride. Particles. The bismuth release agent material according to claim 1, wherein the nanometer cerium nitride has a particle diameter of between 10 and 50 nm. The bismuth release agent material according to claim 1, wherein the cerium nitride accounts for 99% by weight or more. The bismuth release agent material according to any one of claims 1-3, wherein the ratio of the β phase of the tantalum nitride is between 51% and 99%. The bismuth release agent material according to any one of claims 1-3, wherein the ratio of the α phase of the tantalum nitride is between 51% and 99%.