PRODUCTION OF HIGHER SILANE

PURPOSE:To safely obtain high purity higher silanes at a low cost by allowing monosilane to react while circulating under conditions of specified heating temp. range and parameters expressed by specified formula. CONSTITUTION:Monosilane is diluted with inert gas such as N2 so as to obtain 10-80vol.% of monosilane, heated at 350-550 deg.C to produce higher silanes. The unreacted monosilane separated from the higher silanes is circulated to be used again as the source material. Thus, higher silanes can be obtained at high yield at a low cost under the following condition. The condition is that the variable K expressed by the formula is required to be 13-18. By this method, such problems as deposition of solid Si and production of nonvolatile higher silanes above tetrasilane can be suppressed. Moreover, impurities such as oxygen, carbon, etc., can be prevented from intruding into the products by using high purity monosilane as the source material.