Survey of the preparation, purity, and availability of silanes

Silane and disilane are currently available as prepared for the semiconductor market. Published or public information on preparative methods for monosilane and higher silanes are discussed. Purification techniques are reviewed. Data from current silane suppliers are tabulated. A short review of the silanes in Japan is given. Analytical procedures are not now perfected to determine group 3 or 5 elements in silane. All commercial silanes contain certain impurities. There is no simple one step purification technique for silane which a user could easily operate. Typical and actual analyses of commercial silane are given. Disilane is still in the development stage with only small quantities available at very high prices. The silane process developed in part under the DOE/JPL Flat Plate Solar Array project by Union Carbide is summarized. Higher purity silanes are now appearing on the market. These should be useful in the photovoltaic area.