Removal of moisture from hydrazine
AssigneeMatheson Tri-Gas, Inc.
InventorsHideharu Shimizu, Mark Raynor, Daniel Tempel, Robin Gardiner, Daniel Alvarez, Jr.
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Abstract
The present invention generally relates to the field of gas and liquid phase desiccation. In particular, the present invention relates to methods for removing moisture (and hence oxygen precursors) from hydrazine, thereby providing a high purity source gas suitable for use in vapor deposition processes, such as but not limited to, chemical vapor deposition (CVD) or an atomic layer deposition (ALD).
Claims25
A process for removing moisture from hydrazine in either in a vaporous or aqueous state, comprising:
- contacting hydrazine containing moisture with a scavenger wherein the scavenger comprises a support having associated therewith an active scavenging moiety selected from one of more members of the group consisting of:
- alkali metal compounds, alkaline earth metal compounds, metal oxide or hydroxide compounds and silica-based material wherein after contacting said hydrazine containing moisture with said scavenger the moisture in said hydrazine is removed to a level of less than 2440 ppm.
A method of removing trace amount of moisture from a water contaminated hydrazine, comprising:
- (a) providing a purifying material having an alkali metal compound dispersed on a support;
- and (b) flowing said contaminated hydrazine through said purifying material wherein after flowing is completed the moisture is removed from the contaminated hydrazine to a level below about 0.5 parts per million.
A method of removing trace amount of moisture from a water contaminated hydrazine, comprising:
- (a) providing a purifying material having a metal oxide compound having the formula MxOy wherein M is selected from the group consisting Na, K, Li, Rb, Cs, Mg, Ca, Sr and Ba dispersed on a support, and wherein x is an integer from 1-6 and y is an integer of 1-12;
- and (b) flowing said contaminated hydrazine through said purifying material wherein after flowing is completed the moisture is removed from the contaminated hydrazine to a level below about 1 parts per million.
A method of removing trace amount of moisture from a water contaminated hydrazine, comprising:
- (a) providing a silica-based material comprising silica and alumina with a silica to alumina mole ratio greater than 800;
- and (b) flowing said contaminated hydrazine through said silica-based material wherein after flowing is completed the moisture is removed from the contaminated hydrazine to a level below about 1 parts per million.
A method of drying hydrazine to water levels below 5 ppb, comprising:
- mixing hydrazine with an ionic liquid and storing said mixture in a vessel;
- releasing from said mixture a hydrazine gas;
- and
- directing said hydrazine gas through a purifier material wherein said purifier material comprises a support having associated therewith an active scavenging moiety selected from one of more members of the group consisting of:
- alkali metal compounds, metal oxide or hydroxide compounds and silica-based material.
A method of drying hydrazine to water levels below 1 ppb, comprising contacting hydrazine with an ionic liquid thereby forming a hydrazine/ionic liquid mixture;
- suppressing the gas phase moisture levels in said hydrazine/ionic liquid mixture by changing the partitioning of water between the gas and liquid phase of said hydrazine/ionic liquid mixture.
Dependencies are inferred from the claim text.