JPH0218379A - Device for pulling up semiconductor single crystal - Google Patents

Abstract

PURPOSE:To obtain the title pulling up device capable of preventing a pulled-up single crystal semiconductor from being adversely affected by the impurities of a carbon member, etc., by forming a crucible with a quartz glass crucible and a crucible made of high-purity Mo or W and holding the quartz glass crucible, and making a heater from high-purity Mo or W. CONSTITUTION:A quartz crucible 20 consisting of a high-purity split body and a high-purity Mo crucible 22 holding the crucible 20 are provided in a high- purity opaque quartz glass vessel 29 of the device 2 for pulling up a semiconductor single crystal. An Mo heater 24 coated with high-purity Mo is provided outside the crucible 22. A heat-insulating cylinder 26 consisting of an SiC porous body is furnished around the heater 24, and a reflector 25 with the surface coated with an SiO2 film is provided inside the cylinder 26. An Si seed crystal 28' is rotated in direction of the arrow D, and pulled up in direction of the arrow C by a lifting means 27. By this method, an excellent Si single crystal 28 having a long lifetime and low OSE density can be obtained.

Description

[Detailed description of the invention] ・No.1 The present invention relates to a semiconductor single crystal pulling apparatus.

Juju and medicine - Semiconductor single crystals used as substrates for semiconductor devices (
In particular, silicon single crystals are mainly manufactured by the CZ method.

Here, the C7 method will be briefly explained. First, a polycrystalline silicon raw material, for example, is loaded into a crucible, and the polycrystalline silicon raw material is melted by heating from the surroundings. Next, a seed crystal is suspended from above, immersed in a silicon melt, and then pulled up to produce a silicon-in-crystal ingot.

The crucible is generally made of quartz glass. A carbon crucible is used to support this quartz glass crucible, and a carbon heater and a carbon heat insulating material are provided roughly outside the crucible. Further, the semiconductor single crystal pulling device is surrounded by a metal container (also referred to as a chamber), and this container is cooled with water. Conventional semiconductor single crystal pulling apparatuses have usually been configured as described above.

As mentioned above, the crucibles, heaters, and heat-insulating tubes used for pulling and placing semiconductor single crystals are made of carbon. Therefore, when used in combination with a silica glass crucible, there are various drawbacks as follows.

That is, when pulling a silicon single crystal, the quartz glass crucible is eroded by the silicon melt (Equation 0), and the oxygen content in the silicon melt increases.

5i02→-8i→2Si O・・・・・・・・・0 formula Some of the oxygen in this silicon melt is released outside the melt as SiO due to the difference in vapor pressure between oxygen and silicon. be done. Moreover, it is incorporated into the silicon single crystal being pulled, causing micro defects in the silicon single crystal.

On the other hand, the MCZ method has recently attracted attention for the purpose of reducing the oxygen concentration in such silicon single crystals. According to the MCZ method, convection of silicon melt in a silica glass crucible is suppressed by a magnetic field. Therefore, the erosion of the quartz glass crucible by the silicon melt is reduced, and the oxygen concentration in the silicon single crystal is reduced by 111 degrees. However, C7 method, MC
None of the Z-methods solves the following problem.

That is, SiO released from the silicon melt reacts with carbon in the carbon crucible and carbon heater, and CO is generated (second equation sto+c→Si+GO...
......Formula 0 This Co is taken into the silicon melt again, and the carbon concentration in the pulled silicon single crystal increases, causing micro defects. In particular, the carbon heater reaches the highest temperature among all carbon members, so
When pulling a silicon single crystal, there is a strong reaction with 8i0,
It becomes the largest source of carbon.

The FZ method can be considered as a method for reducing carbon-11 carbon content in silicon single crystals. However, the FZ method requires considerable cost, and it is difficult to increase the diameter of the silicon single crystal to be pulled.

For this reason, the FZ method is used only for special purposes.

Furthermore, heat insulating materials such as carbon crucibles, carbon heaters, and carbon materials tend to adsorb impurity gases. In particular, the heat insulating material located outside the carbon heater is used in combination with carbon felt or the like to improve heat insulation. Therefore, it has a large surface area and easily adsorbs gas. Impurities adsorbed on the carbon member are released into the semiconductor single crystal pulling apparatus again at high temperatures, causing contamination. When impurities are mixed into the silicon melt, dislocations and the like are likely to occur in the silicon single crystal, causing a decrease in yield.

Furthermore, the heat insulating material made of carbon placed outside the carbon heater has poor insulation properties, and the metal container covering the semiconductor single crystal pulling device must be cooled with water. This has the disadvantage of poor thermal efficiency.

On the other hand, crucibles, heaters, and heat insulating tubes made of carbon have poor insulation properties, which also has a negative impact on thermal efficiency.

Furthermore, since the inside of the device is heated by a heater and reaches a high temperature, particles containing impurities are likely to be generated from the carbon felt, etc., and have an adverse effect on the silicon single crystal to be pulled.

Further, impurities such as Fe and Cu are generated from the gold irI container. When these are adsorbed to heat insulating materials and released again at high temperatures, they contaminate the inside of semiconductor single crystal devices. Therefore, dislocations and the like are likely to occur in the semiconductor single crystal.

11 to 11 The present invention aims to solve the various problems mentioned above, and in particular eliminates the adverse effects that a pulled single crystal semiconductor receives from impurities such as carbon members or F (41CLI), and improves thermal efficiency. The purpose is to provide a semiconductor single crystal pulling device.

The single crystal pulling device of the present invention includes a crucible rotatably provided in a container, a heater provided outside the crucible, and a heat insulating material provided outside the heater, and is suspended rotatably. In a semiconductor single crystal pulling apparatus configured to produce a single crystal semiconductor by pulling a seed crystal, the crucible is composed of a quartz glass crucible and a high-purity Mo or W crucible that holds the quartz glass crucible, and the heater is a high-purity crucible. composed of Mo or W,
A reflector is installed outside the heater, the heat insulating material is made of SiC porous material, and the container is made of quartz glass or S
t-S; Characterized by being composed of C.

At least the inner surface of this high-purity Mo or W crucible contains high-purity Mol! LMo compound film, high purity W film or W
A compound film may also be coated. The coating of the film is performed, for example, by the CVD method.

Preferably, this reflector is made of Mo or W. Furthermore, in order to prevent the influence of impurities contained in the reflector, it is advantageous to coat at least the inner surface of the reflector with a layer of high purity SiO2. The reflector may be placed in close contact with the inner surface of the heat insulating material.

This high-purity Mo or W heater may be coated with a high-purity Mo film, a Mo compound film, a high-purity W film, or a W compound film. The coating of the film is performed, for example, by the CVD method.

It is advantageous for the porous SiC body to have a porosity of 15 to 60%.

The reason for limiting the porosity is that if the porosity is 15% or less, the heat insulation properties will be poor, and if the porosity is 60% or more, the strength will decrease.

When the container is constructed from a plurality of components, some of the components may be made of quartz glass or 5-St C. Of course, the container can also be made of quartz glass or gas-impermeable material.

1-''L [Crucible made of Mo or W] A crucible made of Mo or W hardly reacts with a silica glass crucible even at high temperatures when pulling a silicon single crystal.

In addition, it does not easily react with the generated SiO gas, and the SiO gas can be smoothly exhausted.

Since no CO gas is generated in this way, the carbon concentration in the silicon single crystal to be pulled can be significantly reduced. Furthermore, since the generated SiO can be smoothly exhausted, the oxygen concentration can be reduced.

Furthermore, the Mo crucible of the present invention has almost no adsorption of impurities such as Fe and Cu compared to a carbon crucible.

[Reflector 1 During single crystal pulling, the reflector blocks radiant heat emitted from the heater, so thermal efficiency is greatly improved.

Further, by placing the reflector at Wa, the temperature of the heat insulating material does not become high even when pulling a single crystal. Therefore, the impurities adsorbed on the heat insulating material are prevented from being released into the semiconductor single crystal pulling apparatus again and contaminating the inside of the apparatus or being mixed into the melt. Furthermore, for the same reason, particles containing impurities are suppressed from being generated from carbon felt or the like in the heat insulating material.

[Heater made of Mo or W] A heater made of Mo or WFJ is difficult to react with SiO gas generated at high temperatures during pulling of a silicon single crystal, and can smoothly exhaust SiO gas.

Therefore, since CO gas, which is a problem when using a carbon heater, is not generated, the carbon concentration in the single crystal to be pulled is significantly reduced. Furthermore, since the generated SiO can be smoothly exhausted, the oxygen S degree is also reduced.

Furthermore, Mo or Wl! The J heater hardly adsorbs impurities such as FO9Cu compared to the carbon heater.

[Heat Insulating Material Made of SiC Porous Body] A heat insulating material made of a porous SiC body hardly reacts with SiO gas even at high temperatures during pulling of a silicon single crystal, and smoothly exhausts SiO gas.

Therefore, CO gas, which is a problem when using a carbon moisturizer, is not generated from the SiC porous body, and the carbon concentration in the silicon single crystal to be pulled is reduced. In addition, the generated Si
Since O can be smoothly exhausted, the amount of oxygen in the single crystal is reduced.

Furthermore, the heat insulating material made of the SiC porous body of the present invention has a smaller specific surface area and a smoother surface than a heat insulating material made of carbon. Therefore, there is almost no adsorption of impurities such as FO.

[Container made of quartz glass or st-st c] The quartz glass container or the Si-SiC container of the present invention has higher heat resistance than a metal container. Therefore, it can be used without water cooling, and thermal efficiency is greatly improved.

Moreover, the container of the present invention is made of high purity SiO2 or Si-8
Since it is composed of i C, l”e like a metal container.
It does not become a source of 1Qu etc. Therefore, the interior of the semiconductor crystal pulling apparatus is kept clean. Therefore, a single crystal semiconductor with good quality can be obtained.

FIG. 1 shows an embodiment of an apparatus for pulling crystals in a semiconductor according to the present invention.

A crucible is provided in the container 29 of the semiconductor single crystal pulling apparatus 2. The container is pure 1! It is composed of a chamber main body 29a made of opaque quartz glass of f[99°995%, a chamber upper member 29C, and a chamber lower member 29b. The crucible is composed of a quartz crucible 20 made of high-purity divided bodies and a high-purity Mo crucible 22 that holds the quartz crucible 20. The crucible 22 made of Mo is coated with high-purity Mo. The coating is made of high purity Mo (
This was carried out using CVD method using Go) 6 as a raw material.

The crucible is rotatable in the direction of arrow B and can be moved up and down in the direction of arrow A.

A heater 24 made of Mo is provided outside the crucible.

The heater 24 is coated with high purity Mo. Coating is high NiN11(7)(Co)e
was used as a raw material, and the CVD method was used.

Around the heater 24 is a heat insulating cylinder 2 made of porous SiC material.
6 is a provision.

Mo! inside the heat insulation cylinder! A J-glue flaper 25 is provided. This surface is coated with 3i021! by CVD method. is covered.

Seed crystal pulling means 27 is provided above the crucible. The pulling means 27 pulls up the silicon seed crystal 28' in the direction of arrow C while rotating it in the direction of arrow C.

Using this semiconductor single crystal pulling apparatus, 35 kg of high-purity silicon was pulled under conditions of approximately 11111/l1lin to obtain a silicon single crystal 18 with a crystal orientation <100) and a diameter of 5 inches.

[Comparative Example 1] Using a carbon crucible with the same dimensions as the Mo crucible in Example 1, a silicon single crystal was grown in the same manner as in the example using a conventional semiconductor single crystal pulling apparatus that uses a carbon heater and a carbon heat-insulating cylinder. I pulled it up. Note that the reflector is not included in the configuration.

Table 1 shows the lifetime and O8F density of the silicon single crystals pulled in Example 1 and Comparative Example.

Note that the characteristics of a silicon single crystal pulled by the MCZ method are also described as Reference Example 1.

If J is shown in Table 1, in Example 1, a silicon single crystal with a longer lifetime was obtained compared to the conventional example. this is,
This means that the SiO, Co gas generated during pulling of the silicon single crystal was smoothly exhausted, less of it was taken into the silicon single crystal, and the atmosphere was clean.

In addition, since Mo and W crucibles are difficult to adsorb impurities such as Fe and Cu, contamination by heavy metals during single crystal pulling is greatly reduced and the atmosphere is clean, resulting in good silicon single crystals with low O8F density. Obtained.

Furthermore, in Example 1, since the generation of crystal defects can be suppressed during pulling of a silicon single crystal, Dislocation
(dislocations) are less likely to occur, resulting in a significant improvement in yield.

By the way, the present invention is not limited to the above-described embodiments. In the embodiment, the chamber main body 19a, chamber upper member 19C, and chamber lower member 19b as a container were formed of quartz glass or 5-8iC, but a part of the container,
For example, only the chamber body 19a may be made of quartz glass or
-st c may be formed. In this case, the chamber upper and lower members are made of metal.

It is also possible to form each member of the chamber using both quartz glass and 5i-stc materials. Further, the shape of the container, the configuration of the single crystal pulling device, etc. are not limited to the above-mentioned embodiments, and various conventionally used types can be adopted.

11 to 11 According to the semiconductor single crystal pulling apparatus according to the present invention, a good silicon single crystal with a long lifetime and a low O8F density can be obtained. Further, since the generation of crystal defects can be suppressed, the yield can be significantly improved. Furthermore, efficiency in pulling a single crystal semiconductor can be improved.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an embodiment of a semiconductor single crystal pulling apparatus according to the present invention. 2...Semiconductor single crystal pulling device 20...Quartz crucible 22...Carbon crucible 24...Carbon heater 25...Reflector 26...Moisturizing tube 27...Seed crystal pulling Means 28... Silicon single crystal 29... Container 29a... Chamber body 29b... Chamber lower member 29c... Chamber upper member Table 1, Figure

Claims (1)

[Claims] A configuration that includes a crucible that is rotatably installed in a container, a heater that is installed outside the crucible, and a heat insulating material that is installed outside the heater, and that pulls up a rotatably suspended seed crystal to produce a single crystal semiconductor. In the semiconductor single crystal pulling apparatus of A reflector is installed in the area, and the heat insulating material is made of SiC porous material.
Furthermore, a semiconductor single crystal pulling apparatus characterized in that the container is made of quartz glass or Si-SiC.