Process for removing gaseous contaminating compounds from carrier gases containing halosilane compounds
AssigneeWacker-Chemitronic Gesellschaft fur Elektronik-Grundstoffe mbH
InventorsHelene Prigge, Robert Rurlander, Harald Hoffman, Hans-Peter Bortner
Life of this patent
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Abstract
A process for removing contaminants, particularly dopant, from halosilane-containing carrier gases, such as those which are produced in the production of high-purity silicon. The process of the invention is perferably carried out with aid of zeolites which has a low proportion of aluminum and are used in the anhydrous state by bringing the zeolites into contact with the carrier gases. Zeolites, after use, can be regenerated and re-used by increasing the temperature and/or decreasing the pressure of the procedure.
Claims12
A process for removing gaseous contamination selected from the group consisting of n-type doping impurities, p-type doping impurities, hydrocarbons, halogenated hydrocarbons, volatile metal halides, from a carrier gas selected from the group consisting of noble gases and hydrogen, containing halosilane compounds, comprising the steps of:
- bringing the carrier gas into contact with a zeolite of the composition M.sub.2/n O.Al.sub.2 O.sub.3.x SiO.sub.2.y H.sub.2 O wherein,
- M represents an element from Group I or Group II of the Mendeleyev Periodic Table of elements, or represents NH.sub.4 ;
- n corresponds to the valency of M;
- x in which the molar ratio x=SiO.sub.2 /Al.sub.2 O.sub.3 is at least 2;
- and,
- y has a value tending toward zero,
- said zeolite having an unobstructed pore size of 4-20 .ANG.;
- said zeolite being a member selected from the group consisting of zeolite X, zeolite Y, chabazite, pentasil and a combination thereof;
- adsorbing, at least partially, the said contamination to the said zeolite;
- and
- recovering the said carrier gas containing halosilane compounds.
A process for removing gaseous contamination selected from the group consisting of n-type doping impurities, p-type doping impurities, hydrocarbons, halogenated hydrocarbons, volatile metal halides, from a carrier gas selected from the group consisting of noble gases and hydrogen, containing halosilane compounds, comprising the steps of:
- bringing the carrier gas into contact with a zeolite of the composition M.sub.2/n O.Al.sub.2 O.sub.3.x SiO.sub.2.y H.sub.2 O wherein,
- M represents an element from the Group I or Group II of the Mendeleyev Periodic Table of elements, or represents NH.sub.4 ;
- n corresponds to the valency of M;
- x in which the molar ratio x=SiO.sub.2 /Al.sub.2 O.sub.3 is between 2.4 and 120, and
- y has a value tending toward zero,
- said zeolite being a member selected from the group consisting of zeolite X, zeolite Y, chabazite, pentasil and a combination thereof;
- said zeolite having an unobstructed pore size of 5.5-20 .ANG., said bringing into contact step is carried out at a temperature of 0.degree. to 50.degree. C., said bringing into contact step is carried out at a pressure of 0.5 to 10 bar;
- adsorbing, at least partially, the said contamination to the said zeolite;
- and
- recovering the said carrier gas containing the halosilane compounds.
Dependencies are inferred from the claim text.