Silicon carbide single crystal, substrate and preparation method thereof

Abstract

The invention discloses a silicon carbide single crystal, a substrate and a preparation method thereof, which belongs to the field of semiconductor materials. The preparation method of the silicon carbide single crystal comprises the following steps: forming a low-temperature region and a high-temperature region in a crucible by virtue of a temperature measuring hole formed in an upper thermal insulation layer group outside the crucible, and transmitting a raw material gas phase in the low-temperature region to the surface of a seed crystal in the high-temperature region by virtue of a physical gas phase transmission method to grow the crystal; wherein the upper heat preservation layer set comprises a second heat preservation layer and a first heat preservation layer which are sequentiallyarranged in the seed crystal direction of raw materials. The first heat preservation layer is provided with a first opening, the second heat preservation layer is provided with a second opening, anda rotary adjusting mechanism rotates the first heat preservation layer and / or the second heat preservation layer to adjust the cross sectional area of a temperature measuring hole formed by the firstopening and the second opening, so that the axial and radial temperature gradient in the crucible in the crystal growth process is adjusted. According to the preparation method of the silicon carbidesingle crystal, the radial temperature gradient in a growth cavity for growing the single crystal can be adjusted; and while the radial temperature gradient is reduced, a certain axial temperature gradient is ensured, and the high-quality silicon carbide single crystal is efficiently prepared.

Description

technical field [0001] The application relates to a silicon carbide single crystal, a substrate and a preparation method thereof, belonging to the field of semiconductor materials. Background technique [0002] Silicon carbide single crystal is one of the most important third-generation semiconductor materials. It is widely used in power electronics, RF devices, optoelectronic devices and other fields. [0003] At present, the main preparation method of silicon carbide single crystal is physical vapor transport (PVT) method. In the process of preparing single crystal by PVT method, there are radial temperature gradient and axial temperature gradient in the growth chamber of growing single crystal. In the stable growth stage of single crystal, a larger axial temperature gradient has a faster single crystal growth rate, and a smaller radial temperature gradient can reduce the introduction of stress and dislocation. However, it is difficult to simultaneously achieve a large ...

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Problems solved by technology

The existing induction coil heating method, on the one hand, is difficult to increase the axial temperature gradient of the growth chamber without affecting the radial temperature gradient and ensure a small radial temperature gradient; on the other hand, when reducing the radial temperature gradient , the axial temperature gradient also has a large drop, and the growth rate cannot be guaranteed

In addition, it is difficult to control the radial temperature gradient in a large range during the growth process of silicon carbide single crystal in the current equipment, and it is difficult to realize the change of radial temperature gradient required in the growth of silicon carbide single crystal

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