High purity tungsten hexachloride and method for making same
View Patent ↗Condensable metal halide materials, such as but not limited to tungsten chloride (WCl 6 ), can be used to deposit metal films or metal containing films in a chemical vapor deposition (CVD) or atomic layer deposition process. Described herein are high purity compositions comprising condensable materials and methods to purify condensable materials. In one aspect, there is provided a composition comprising: tungsten hexachloride which is substantially free of at least one impurity and wherein the tungsten hexachloride comprises at least 90%, preferably 95% and more preferably 99% by weight or greater of a β-WCl 6 and 5% by weight or less of the α-WCl 6 as measured by X-ray diffraction.
1. A composition for depositing a tungsten film or tungsten-containing film by a chemical vapor deposition or atomic layer deposition process, the composition comprising:
at least 99% by weight or greater of β-WCl 6 .
2. The composition of claim 1 , wherein the composition further comprises 1% by weight or less of WOCl 4 .
3. The composition of claim 1 , wherein the composition comprises 1% by weight or less of α-WCl 6 .
4. The composition of claim 3 , wherein the composition comprises at least 99.9% by weight or greater of β-WCl 6 .
5. A delivery system for depositing a tungsten film or tungsten-containing film comprising:
a composition comprising at least 90% by weight or greater of β-WCl 6 ;
a vessel; and
wherein the composition is inside the vessel and the vessel is maintained at a temperature ranging from 140° C. to 200° C.
6. The delivery system of claim 5 , wherein the composition comprises at least 95% by weight or greater of β-WCl 6 and 5% by weight or less of α-WCl 6 .
7. The delivery system of claim 5 , wherein the composition comprises at least 99.9% by weight or greater of β-WCl 6 and 1% by weight or less of α-WCl 6 .
8. The delivery system of claim 5 , wherein the composition comprises at least 99.9% by weight or greater of β-WCl 6 .
9. A process of preparing a delivery system for depositing a tungsten film or tungsten-containing film comprising:
providing a vessel;
providing a composition comprising at least 90% by weight of WCl 6 wherein the composition is inside the vessel; and
heating and maintaining the vessel to have at least 90.0% by weight of WCl 6 is β-WCl 6 .
10. The process of claim 9 , wherein the heating is performed until 95.0% by weight of WCl 6 is β-WCl 6 .
11. The process of claim 9 , wherein the heating is performed until 99.0% by weight of WCl 6 is β-WCl 6 .
12. The process of claim 9 , wherein the heating is performed until 99.9% by weight of WCl 6 is β-WCl 6 .
13. The process of claim 9 , wherein the vessel is heated and maintained at a temperature of 140° C. to 200° C.
14. A system for purifying a crude material comprising WCl 6 and at least one impurity comprising:
(a) at least one boiler;
(b) a condenser;
(c) a connector in fluid communication with the boiler and the condenser;
(d) a carrier gas in fluid communication with the boiler; and
(e) a fluidizing gas in fluid communication with the connector and the condenser;
wherein
the at least one impurity comprising at least one of trace metals, tungsten oxytetrachloride (WOCl 4 ), and tungsten pentachloride (WCl 5 );
the at least one boiler is maintained at a temperature above the boiling point of WCl 6 to convert filled crude material to gaseous phase mixing with the carrier gas to obtain boiler vapor stream;
the connector is filled with the boiler vapor stream;
the condenser containing the fluidizing gas mixing with the boiler vapor stream to obtain a condenser vapor containing purified material comprising WCl 6 at the bottom of the condenser while the fluidizing gas carrying the at least one impurity to the top of the condenser;
the carrier gas and the fluidizing gas are not react with WCl 6 ; and
the fluidizing gas is cooler than the boiler vapor stream.
15. The system of claim 14 , wherein the at least one boiler is maintained at >300° C.; and the condenser vapor is maintained at one or more temperatures ranging from about 100 to about 180° C.
16. The system of claim 14 ; wherein a molar ratio of the fluidizing gas and the boiler vapor stream is <200:1; and a molar ratio of the carrier gas to the crude material in the boiler vapor stream is <10:1.
17. The system of claim 14 ; wherein the condenser further comprises a dip tube in fluid communication with a vacuum pump to withdraw the purified material comprising WCl 6 from the bottom of the condenser.
18. The system of claim 14 ; wherein the purified material comprising WCl 6 comprises at least 90% by weight or greater of β-WCl 6 .
19. The system of claim 14 ; wherein the purified material comprising WCl 6 comprises at least 99% by weight or greater of β-WCl 6 .
20. The system of claim 14 ; wherein the system further comprises a vessel in fluid communication with the dip tube for housing the purified material comprising WCl 6 wherein the purified material comprising WCl 6 comprises at least 90% or 99% by weight or greater of β-WCl 6 .