Device and method to producing single crystals by vapour deposition
AssigneeNorstel AB
InventorsErik Janzen, Peter Raback, Alexandre Ellison
Life of this patent
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Abstract
A method and a device to grow from the vapor phase, a single crystal of either SiC, a group III-nitride, or alloys thereof, at a growth rate and for a period of time sufficient to produce a crystal of preferably several centimeters length. The diameter of the growing crystal may be controlled. To prevent the formation of undesirable polycrystalline deposits on surfaces in the downstream vicinity of the single crystal growth area, the local supersaturation of at least one component of the material grown is lowered by introducing a separate gas flow comprising at least one halogen element or a combination of said halogen and hydrogen species.
Claims16
A method for growing large, single polytype, compound crystals of one of a) silicon carbide, b) a group III-nitride c) alloys thereof, the method comprising:
- providing, in a heated growth enclosure comprising a seed crystal, a mixture of vapor species containing at least the elements of the compound crystal, in such a way that, at least one of the elements is continuously fed into the enclosure through an opening upstream of a growth surface of said crystal,
- providing a separate opening downstream of the growth surface of said crystal to remove a continuous flow of remaining vapor species not having deposited under conditions yielding to growth of said crystal,
- providing an additional gas flow containing at least one halogen element, in such a way that, said gas flow is heated and decreases a deposition rate of solid phases downstream of the growth surface of said crystal.
A device for producing large, single polytype, compound crystals of one of a) silicon carbide, b) a group III-nitride c) alloys thereof, the device comprising:
- a susceptor having circumferential walls surrounding a room for receiving a seed crystal,
- means for continuously feeding in a vapor state or in a liquid state at least one of the elements of said crystal through one or several conducts upstream of a growth surface of said crystal,
- means for continuously removing from the room the flow of remaining vapor species not having deposited under conditions yielding to growth of said crystal, while maintaining a predefined pressure in the growth room,
- means for heating the susceptor and thereby the seed crystal to a predetermined process temperature
- the device further comprising one of more of:
- means to continuously feed and control an etching gas mixture comprising an halogen and hydrogen into a conduit of a rotating shaft supporting a seed crystal holder and said conduit communicating with a region downstream of the seed crystal,
- means to continuously feed and control an etching gas mixture comprising an halogen and hydrogen into conduits designed to open into a downstream room of the susceptor, said downstream room being in contact with an upstream room of the susceptor extending until the initial position of the seed holder,
- means to continuously feed and control an etching gas mixture comprising an halogen and hydrogen into a circumferential conduit delimited by the inner wall of the upstream room of the susceptor and the outer wall of an inner crucible, said inner crucible extending along a symmetry axis parallel to said crystal growth direction and terminating in the immediate upstream vicinity of the initial seed crystal position.
A device for producing large, single polytype, compound crystals of one of a) silicon carbide, b) a group III-nitride c) alloys thereof, the device comprising:
- a crucible having circumferential walls surrounding a room for receiving a seed crystal in its upper part and a solid source, for example a powder, containing the elements of the compound semiconductor to be grown,
- means for heating the susceptor and establishing a temperature between the source material and the seed crystal,
- effusion openings in the crucible, and
- means to feed or diffuse a continuous flow of a gas mixture containing at least one halogen element in the immediate vicinity of said effusion opening so as to maintain over a desired amount of time said opening free of solid deposits resulting from the condensation of any vapors sublimed from the source material.
Dependencies are inferred from the claim text.