JPH0218380A - Device for pulling up semiconductor single crystal - Google Patents

Abstract

PURPOSE:To obtain the title pulling up device especially capable of preventing the pulled-up single crystal semiconductor from being adversely affected by a carbon member by providing a freely rotatable crucible, a heater outside the crucible, and a heat-insulating material formed by an SiC porous body outside the heater in a vessel. CONSTITUTION:A crucible consisting of a quartz crucible 10 formed with a high-purity split body and a carbon crucible 12 holding the crucible 10 is provided in the vessel 19 of the device 1 for pulling up a semiconductor single crystal. A carbon heater 14 is provided outside the crucible, and a heat-insulating cylinder 16 formed with an SiC porous body is furnished around the heater 14. An Si seed crystal 18' is rotated in direction of the arrow D to pull up an Si single crystal 18 in direction of the arrow C by a lifting means 17 provided above the crucible. By this pulling up device, the contamination with the gaseous impurities, heavy metals, etc., is reduced at the time of pulling up the Si single crystal, hence the yield is drastically improved, and a remarkable effect is produced.

Description

[Detailed description of the invention]

− of The present invention relates to a semiconductor single crystal pulling apparatus.

[1111 Semiconductor single crystal used as a substrate for semiconductor devices (
In particular, silicon single crystals are mainly manufactured by the C7 method. Here, the CZ 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 silicon melt, and pulled up to produce a silicon single 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 moisturizing 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 medium crystal pulling apparatuses have usually been configured as described above. As mentioned above, the crucibles, heaters, and heat-insulating cylinders used in such semiconductor single crystal pulling equipment 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 corroded by the silicon melt (Equation 0), and the oxygen concentration in the silicon melt decreases. 5i02+Si→2Si O...0 Formula A part of the oxygen in the silicon melt is released outside the melt as SiO due to the difference in vapor pressure between oxygen and silicon. In addition, it is incorporated into the pulled silicon single crystal,
Causes micro defects in silicon single crystals. 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. However, neither the C7 method nor the MCZ method solves the following problem. That is, 3i0 released from the silicon melt reacts with carbon in the carbon crucible and carbon heater, and CO is generated (second equation sto+c→S++CO...
......Formula 0 This CO is taken into the silicon melt again, increasing the carbon concentration in the pulled silicon single crystal and causing micro defects. F is a method for reducing the carbon concentration in silicon single crystals.
The Z method can be considered. 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, the carbon member, especially the heat insulating material located outside the carbon heater, is used in combination with carbon felt or the like to improve the heat insulation properties. Therefore, the surface area is large,
Moreover, it 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, etc. 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. For this reason, it has the disadvantage of poor thermal performance. Furthermore, since the inside of the apparatus is heated by a heater and reaches a high temperature state, 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. SUMMARY OF THE INVENTION The present invention aims to solve the various problems mentioned above, and particularly aims to provide a semiconductor single crystal pulling apparatus that eliminates the adverse effects of a carbon member on a pulled single crystal semiconductor. 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 a seed suspended rotatably. Semiconductor single crystal pulling e*, which is configured to produce a single crystal semiconductor by pulling a crystal, is characterized in that the heat insulating material is made of a SiC porous body. 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. Furthermore, in order to prevent the generation of Co gas, it is preferable that the heater and crucible be made of a material other than carbon, such as M or W. A heat insulating material made of a one-plate SiC porous material does not easily react with SiO gas even at a temperature of a when pulling a silicon single crystal, and smoothly exhausts SiO gas. Therefore, Co gas, which is a problem when using carbon-based heat insulating materials, 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 crystal A is also 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 heat insulating materials made of carbon. Therefore, there is almost no adsorption of impurities such as [e]. Support 11 FIG. 1 shows an embodiment of a semiconductor single crystal pulling apparatus according to the present invention. A crucible is provided in the container 19 of the semiconductor single crystal pulling apparatus 1 . The container is composed of a chamber main body 19a, a chamber upper part +419c, and a chamber lower member 19b. The crucible t is composed of a quartz crucible 10 made of high-purity divided bodies and a carbon crucible 12 that holds the quartz crucible 10. The crucible is rotatable in the direction of arrow B and can be moved up and down in the direction of the arrow. A carbon heater 14 is provided outside the crucible. Around the heater 14 is a heat insulating cylinder 1 made of porous SiC material.
6 is the step. 5i-C porous body @16 was created as follows. First, 7-enol resin was added to high-purity SiC powder with pure Jff 99.8% and average particle size 20-5μ, cross-wire granulated, dried, and then molded with an assostatic press to an external diameter of 666.
A molded body having an inner diameter of 5471 mm, a height of 562 mm, and a height of 562 mm was obtained. Next, this was heated at 200°C to harden the phenol resin. Thereafter, it was heated and fired at 100° C., and then purified with HC9 gas to produce a heat-retaining cylinder made of a porous SiC body with a porosity of 45%. Seed crystal pulling means 17 is provided above the crucible. The pulling means 17 pulls up the silicon hardened product 18' in the direction of arrow C while rotating it in the direction of arrow C. Using this semiconductor single crystal pulling apparatus, 35 kV of high purity silicon was pulled under conditions of about 11 n+/min to obtain a silicon single crystal 18 with a crystal orientation of (100) and a diameter of 5 inches. [Comparative Example] A silicon single crystal was grown in the same manner as in the example using a conventional silicon single crystal pulling apparatus that uses a carbon heater and a carbon heat insulation cylinder, using a carbon heat insulation cylinder with the same dimensions as the SiC porous body of the example. was raised. Table 1 shows the lifetime and O8F density of silicon single crystals pulled in Examples and Comparative Examples. Note that the characteristics of a silicon single crystal pulled by MCZ are also described as a reference example. According to Table 1, in the example, a silicon single crystal with a longer lifetime than in the conventional example was obtained. This is because the SiO, Co gases generated during the pulling of the silicon single crystal are smoothly exhausted, and the m
This means that the atmosphere was clean. In addition, since the adsorption of impurities such as Fe and Qu and the generation of particles are completely eliminated, the atmosphere becomes clean, so 08F
A good crystal in silicon with a low molecular weight of 15a was obtained. Furthermore, in the example, since the generation of crystal defects can be suppressed during pulling of silicon single crystal, Dis+ocatton (
(dislocations) are less likely to occur, resulting in a significant improvement in yield. As detailed above, according to the semiconductor single crystal pulling apparatus of the present invention, contamination by impurity gases, heavy metals, etc. is reduced during pulling of silicon crystals, so that significant effects such as significantly improved yield can be achieved. It is something.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing an embodiment of the semiconductor single crystal pulling he according to the present invention. 1...Semiconductor single crystal pulling device 10...Quartz crucible 12...Carbon crucible 14...Carbon heater 16...Heat retaining cylinder 17...Seed crystal pulling means 18...Silicon Single crystal 19...Reduced pressure container Figure 1 Table 1

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. 1. A semiconductor single crystal pulling apparatus characterized in that the heat insulating material is made of a porous SiC material.