Electrolysis: processes – compositions used therein – and methods – Electrolytic synthesis – Preparing inorganic compound
Patent
1998-06-05
2000-06-27
Phasge, Arun S.
Electrolysis: processes, compositions used therein, and methods
Electrolytic synthesis
Preparing inorganic compound
205550, 204258, 117 99, 438935, C25B 100, C25D 1700, C30B 2814
Patent
active
060802979
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates generally to electrochemical synthesis methods for producing high purity hydride gases for semiconductor fabrication and doping. The invention relates more particularly to the electrochemical synthesis and production of Group IV and V volatile hydrides such as phosphine, arsine, stibine, and germane.
As further background, high purity gases are required for semiconductor fabrication and doping. Often these gases are extremely toxic and hazardous. Hence, centralized production, transportation and storage of these materials presents a hazard to those working with them. On-site electrochemical synthesis of these gases provides an alternative means to provide such gases to the semiconductor industry in a safe manner. The process described below allows the gas to be generated as needed thereby minimizing the amount of gas present prior to use in a semiconductor fabrication reactor. This provides a substantial advantage over the use of compressed gas in cylinders. Commercial compressed gas cylinders store gas at several thousand pounds per square inch pressure and contain one to ten pounds of gas. Hence, gas cylinders present a major chemical release hazard. On-site electrochemical generation of the gas eliminates this hazard.
The following references disclose processes for producing these gases by chemical methods. Cotton and Wilkinson, "Advanced Inorganic Chemistry", Wiley Interscience, Fourth Ed. (1980) and Brauer, "Preparative Inorganic Chemistry", Academic Press (1963) teach that the Group IV and V hydrides can be produced by chemical reduction of electropositive compounds of the desired product gas element with acids or the reduction of the halides with LiAlH.sub.4 or NaBH.sub.4. For example:
These gases can also be prepared by the electrochemical reductions:
In addition, dissolved ionic precursors can be used such as:
Salzberg, J. Electrochem. Soc., 101:528 (1964) discloses the electrochemical formation of stibine at an antimony cathode. Lloyd, Trans. Faraday Soc., 26:15 (1930) and Salzberg, J. Electrochem. Soc., 107:348 (1960) disclose the preparation of high purity arsine at an arsenic cathode. Spasic, Glas. Hem. Drus. Beograd., 28:205 (1963) discloses the electrochemical production of germanium hydride.
E. W. Haycock and P. R. Rhodes (U.S. Pat. No. 3,404,076) disclose a method for the electrolytic preparation of volatile hydrides. Gordon and Miller (U.S. Pat. Nos. 3,109,785 and 3,109,795), Miller and Steingart (U.S. Pat. No. 3,262,871) and Miller (U.S. Pat. No. 3,337,443) disclose electrolytic methods for the production of phosphine.
Porter, in U.S. Pat. No. 4,178,224, discloses an electrochemical method for the synthesis of arsine gas. His method utilizes a dissolved arsenic salt with an oxygen evolving anode. With this method, the arsine concentration was limited to less than 25%. Another limitation of Porter's method was the need to balance pressures and liquid levels in the divided anode and cathode sections of the electrochemical cell. This requires an inert gas supply to the cell.
W. M. Ayers, in U.S. Pat. No. 5,158,656, describes an electrochemical apparatus and method for supplying volatile hydrides at the proper pressure for introduction into a chemical vapor deposition reactor.
While efforts have continued to provide effective means for producing and delivering hydride gases, needs still exist related to the quality and consistency of delivered product streams including hydride gases. The present invention addresses these needs.
SUMMARY OF THE INVENTION
Briefly describing one preferred embodiment of the invention, provided is a method for consistent composition delivery of a product gas stream including a hydride gas. The method includes the steps of: gas, said first gas feed stream having a varying level of hydride gas over time; gas, to form a product gas stream including the diluent gas and the hydride gas; stream; and hydride gas to said diluent gas in said product stream over time, the execution of said control software causin
REFERENCES:
patent: 3109785 (1963-11-01), Gordon
patent: 3109795 (1963-11-01), Gordon
patent: 3262871 (1966-07-01), Miller et al.
patent: 3337443 (1967-08-01), Raetzsch et al.
patent: 3404076 (1968-10-01), Haycock et al.
patent: 4178224 (1979-12-01), Porter
patent: 5158656 (1992-10-01), Ayers
patent: 5425857 (1995-06-01), Bouard et al.
patent: 5573334 (1996-11-01), Anderson
patent: 5925232 (1999-07-01), Ayers
W.V. Lloyd, "The Overpotential Of Arsenic And The Yields Of Arsine At An Arsenic Cathode In Acid Solutions," Transactions of the Faraday Society, vol. XXVI, pp. 15-18 (1930). No Month Available.
H.W. Slazberg and B. Goldschmidt, "Arsine Evolution And Water Reduction At An Arsenic Cathode," J. Electrom. Soc., vol. 107, No. 4, pp. 348-353 (1960). No Month Available.
M. Spasic, D. Vucurovic,. R. Vracar and I. Ilic, "A Contribution On The Hydrometallurgical Production Of Mercury From Mercury Ores Of The Suplja Stena Area--Avala," Glasnik Hemijskog Drustva, vol. 28, Nos. 3-4, pp. 212-222 (1963. No Month Available.
Electron Transfer Technologies, Inc.
Phasge Arun S,.
Wong Edna
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