Vanadium doped SiC single crystals and method thereof
View Patent ↗A sublimation grown SiC single crystal includes vanadium dopant incorporated into the SiC single crystal structure via introduction of a gaseous vanadium compound into a growth environment of the SiC single crystal during growth of the SiC single crystal.
1. A method of growing a vanadium-doped SiC single crystal by sublimation comprising:
(a) providing a growth crucible having SiC source material and a SiC single crystal seed in spaced relation therein;
(b) heating the growth crucible of step (a) to a temperature between 2000° C. and 2400° C. causing the SiC source material to sublime;
(c) forming a temperature gradient between the SiC source material and the SiC single crystal seed that causes the sublimated SiC source material to be transported to and precipitate on the SiC single crystal seed thereby growing a SiC crystal on the SiC single crystal seed; and
(d) concurrent with step (c), introducing into the growth crucible from a location outside the growth crucible a doping gas mixture that includes a gaseous vanadium chemical compound that, in response to entering the growth crucible heated to the temperature between 2000° C. and 2400° C., undergoes thermal dissociation, chemical reduction, or both, releasing into the growth crucible gaseous dissociation products, reduction products, or both which are absorbed on a growth interface of the growing SiC crystal thereby doping the growing SiC crystal with vanadium.
2. The method of claim 1 , wherein the gaseous vanadium chemical compound includes a halogen.
3. The method of claim 2 , wherein the gaseous vanadium chemical compound is vanadium chloride (VCl n ), where n=2, 3, or 4.
4. The method of claim 1 , wherein the doping gas mixture includes a carrier gas.
5. The method of claim 4 , wherein the carrier gas includes an inert gas, hydrogen, or both.
6. The method of claim 4 , wherein the carrier gas includes a halogen additive selected from the group of chlorine and fluorine.
7. The method of claim 4 , wherein:
the gaseous vanadium chemical compound is vapors of the VCl n ; and
the doping gas mixture is comprised of the VCl n vapors mixed with the carrier gas.
8. The method of claim 7 , wherein the VCl n vapors are mixed with the carrier gas by passage of the carrier gas through a pool of liquid VCl n .
9. The method of claim 7 , wherein the VCl n vapors are mixed with the carrier gas by passage of the carrier gas that includes chlorine over the surface of a heated solid vanadium source located outside the growth crucible.