05-12-2013 дата публикации
Номер: US20130320275A1
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In a crystal growth apparatus and method, polycrystalline source material and a seed crystal are introduced into a growth ambient comprised of a growth crucible disposed inside of a furnace chamber. In the presence of a first sublimation growth pressure, a single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a first gas that includes a reactive component that reacts with and removes donor and/or acceptor background impurities from the growth ambient during said sublimation growth. Then, in the presence of a second sublimation growth pressure, the single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a second gas that includes dopant vapors, but which does not include the reactive component. 1. A crystal growth method comprising:(a) providing a SiC single crystal seed and a polycrystalline SiC source material in spaced relation inside of a growth crucible that is disposed inside of a furnace chamber, the growth crucible disposed inside of a furnace chamber defining a growth ambient; and(b) sublimation growing a SiC single crystal on the SiC seed crystal via precipitation of sublimated SiC source material on the SiC seed crystal in the presence of a reactive atmosphere in the growth ambient that removes donor and/or acceptor background impurities from the growth ambient.2. The method of claim 1 , wherein the reactive atmosphere includes a halide vapor compound and one or more gases.3. The method of claim 2 , wherein:the halide vapor compound is comprised of (1) fluorine or chlorine, and (2) tantalum or niobium; andthe one or more gases includes argon, hydrogen, or a mixture of argon+hydrogen.4. The method of claim 2 , further including:(c) following step (b), changing the atmosphere in the growth ambient to a non-reactive atmosphere; and(d) following step (c), introducing ...
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