Purifying method of semi-conductor gas

Abstract

This invention is directed to a method for purifying an impure gas to produce an ultra-high purity gas comprising the steps of a) passing the impure liquefied gas through a first absorption means to remove impurities from the liquid phase therein to produce a first purified fluid; b) passing the first purified fluid through an evaporation means to remove impurities therein to produce a second purified gas; and c) passing the second purified gas through a second absorption means to remove impurities from the vapor phase therein to produce the ultra-high purity gas.

Description

technical field [0001] The present invention relates generally to the purification of gases and, more particularly, to a method of producing purified semiconductor gases free of impurities using absorption and evaporation techniques. Background technique [0002] In the fabrication of semiconductor chips, ammonia is used as a source gas in chemical vapor deposition (CVD) of nitride films. Typical nitrides are silicon nitride formed by the reaction of silane and ammonia, and titanium nitride formed by the reaction of titanium tetrachloride and ammonia. Water vapor levels from 1 to 3000 ppb from ammonia cylinders will lead to a decrease in the performance parameters of the nitride layer. More recently, new GaN CVD technologies have shown that they require lower water content in the ammonia source than silicon nitride and titanium nitride technologies require. To prevent performance problems, the water content must be reduced below 200 ppb. [0003] At present, the specifica...

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Problems solved by technology

Because of these limitations, the concept of using an in-line purifier cannot be used for large-scale purification on the order of thousands of pounds per day

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