Sustained release device for growing of SiC single crystals with PVT (physical vapor transport) method

Abstract

The invention discloses a slow-release device for growing silicon carbide single crystal by PVT method. The device comprises a crucible, a crucible cover is fastened on the crucible, a seed crystal is fixed on the inner side of the crucible cover, and silicon carbide powder is installed in the crucible The crucible is provided with a partition, which separates the silicon carbide powder source into upper and lower layers, and the partition is provided with several holes connecting the upper and lower layers of the silicon carbide powder source. The invention divides the straight-through crucible inner cavity into upper and lower layers, reduces the gas transmission rate from the wall to the seed crystal, effectively solves the problem of Si loss, and at the same time does not change the temperature field distribution in the crucible, and improves the crystal growth quality. Increase the utilization rate of raw materials, reduce the cost of raw materials, and bring benefits to the enterprise.

Description

technical field [0001] The invention relates to the technical field of semiconductor growth, in particular to a slow-release device for growing silicon carbide single crystal by PVT (Physical Vapor Deposition) method. Background technique [0002] The basic process of PVT (physical vapor deposition) silicon carbide (SiC) single crystal growth includes three processes of raw material decomposition and sublimation, mass transport and crystallization on the seed crystal. When heated to a certain temperature, the raw material is mainly decomposed into Si, Si 2 C. SiC 2 gas. When the distance from the raw material to the seed crystal is small (below about 10 mm), the direct sublimation from the raw material surface to the seed crystal is mainly; when the distance is large, the growth is mainly by the gas transport from the wall to the seed crystal. [0003] During the growth process, the first thing to solve is the uniform distribution of the temperature field to ensure the un...

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Problems solved by technology

Another problem is the loss of Si. The vapor pressure of Si is high and the boiling point is low, so it sublimates from the material very early and overflows the crucible.

[0004] Usually, the crucible designed according to the temperature field distribution is a straight-through structure. In the early stage of growth, the raw material far away from the seed crystal will complete a large amount of gas transmission from the wall to the seed crystal, but it will not form a silicon carbide single crystal. , because the vapor pressure of Si is higher than that of other components, the gas Si will react with the graphite wall of the crucible to form Si 2 C. SiC 2 , and overflow the crucible, resulting in the loss of Si, and finally cause the imbalance of Si / C ratio to affect the growth components and temperature field stability

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