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Method of Increasing the Flammability of Silane

IP.com Disclosure Number: IPCOM000121234D
Original Publication Date: 1991-Aug-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 39K

Publishing Venue

IBM

Related People

Beach, DB: AUTHOR

Abstract

A technique is described whereby the addition of higher silane compounds to silane compounds increases the flammability of silane gas mixtures when exposed to air. The concept provides significantly safer storage and handling of silane by rendering spontaneous flammable concentrations below the level where explosive detonation occurs.

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Method of Increasing the Flammability of Silane

      A technique is described whereby the addition of higher
silane compounds to silane compounds increases the flammability of
silane gas mixtures when exposed to air. The concept provides
significantly safer storage and handling of silane by rendering
spontaneous flammable concentrations below the level where explosive
detonation occurs.

      The use and storage of monosilane, SiH4, is made increasingly
hazardous by the unpredictability of the reaction when the compound
is combined with oxygen.  When exposed to air, the compound may burn
immediately, or it may accumulate in enclosed areas and detonate
explosively. Studies have shown [1] that oxidation mixtures of
SiH4/O2 of up to fifty percent SiH4, at atmospheric pressure and
ambient temperatures, did not explode.  The studies also found that
very pure silane, as used in semiconductor fabrication, was
considerably less flammable than silane contaminated with traces of
higher molecular weight silanes.

      In subsequent studies [2], the oxidation of disilane (Si2H6)
and trisilane (Si3H8) showed that the three hydrides form a graded
series, in which the flammability increases with the molecular
weight.

      Therefore, the concept implements the addition of the higher
silanes in the final steps of the manufacture of SiH4, or perhaps
generated "in situ" by passing purified SiH4 through an electric
discharge [3].  This enables the silane to be made reli...