Bonding method of silicon carbide seed crystals and preparation method of silicon carbide single-crystal ingot

Abstract

The invention discloses a bonding method of silicon carbide seed crystals and a preparation method of silicon carbide single-crystal ingot. The bonding method of the silicon carbide seed crystal comprises the following steps: mixing silicon carbide powder, carbon powder and silicon powder, adding a binder, uniformly carrying out mixing to obtain mixed powder, coating a silicon carbide wafer with the mixed powder, placing the silicon carbide seed crystals on the mixed powder, and enabling the seed crystals to be tightly bonded with the silicon carbide wafer under an inert atmosphere at a temperature of 1500-2000 DEG C to obtain the silicon carbide bonded seed crystals, wherein no impurities are introduced. When the silicon carbide bonded seed crystals obtained through the method is used ingrowing the silicon carbide single-crystal ingot through a physical vapor transport (PVT) method in a silicon carbide crystal growth furnace, heat conduction is rapid, heat transfer is uniform, and the high-quality silicon carbide single-crystal ingot can be obtained. According to the method, the feeding space and the feeding amount of the raw materials are increased, so that the size of a singlecrystal ingot is increased, the wafer output of a single crystal ingot is increased, and operation cost of the silicon carbide crystal growth furnace is reduced.

Description

technical field [0001] The invention belongs to the technical field of semiconductor material preparation, and in particular relates to a method for bonding a silicon carbide seed crystal and a method for preparing a silicon carbide single crystal ingot. Background technique [0002] Silicon carbide is a new type of wide-bandgap semiconductor material, which has received more and more attention recently. In some extreme application scenarios, such as high temperature, high frequency and high power applications, it is better than traditional sapphire and silicon. The characteristics of silicon carbide mainly include high melting point, high electrical conductivity, high thermal conductivity and high voltage resistance. Therefore, It has become an important material for high-frequency and high-power devices, and is widely used in important fields such as aviation, aerospace, rockets, and geological drilling. [0003] At present, in the process of preparing silicon carbide sin...

AI Technical Summary

Problems solved by technology

Although all of them can realize the preparation of silicon carbide single crystal ingots, the quality of the obtained ingots is poor and the cost is high

Usually, during the growth process of silicon carbide single crystal ingot, the heat transfer mode has two heat transfer modes: heat conduction and heat radiation. With graphite plate as the heat transfer medium, its heat conduction is not as fast as silicon carbide single crystal, and graphite plate is opaque. , so most of the energy of thermal radiation will be reflected back and forth between the graphite plate and the heating body and dissipated, resulting in low heat utilization efficiency, which in turn affects the temperature field of the grown crystal, resulting in poor quality of the grown single crystal ingot

In addition, the traditional seed crystal bonding method has uneven heating of the seed crystal, which will also affect the quality of crystal growth.

[0004] The traditional silicon carbide bonding seed crystal method is to directly bond the seed crystal to the graphite crucible cover. The disadvantage is that there are many residues on the surface of the used crucible cover, resulting in uneven surface of the graphite crucible cover, which cannot be used many times.

The traditional single crystal ingot preparation method of graphite induction ring is complicated in mechanical design and difficult to process. In addition, the design of its hollow structure limits the amount of raw material input, which is not conducive to mass production of large crystal ingots.

For a fixed silicon carbide crystal growth furnace, the external magnetic induction coil is fixed, and the height of the crucible is also fixed. When the height of the crucible is fixed and the distance between the seed crystal and the raw material is fixed, the position of the seed crystal is closer to the raw material feeding area. Proximity means that the amount of raw material input can only be reduced, which will limit the size of a single crystal ingot, resulting in a decrease in the wafer output of a single crystal ingot, and increasing the operating cost of the silicon carbide crystal growth furnace

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