The preparation, purification, and thermal decomposition of silane, , were investigated for the purpose of preparing high‐purity silicon. Quantitative yields of silane were obtained by the reduction of silicon tetrachloride with lithium aluminum hydride. Variables in the thermal decomposition of silane were evaluated with regard to purity of the elemental silicon produced and the efficiency of dissociation and deposition rate. Silane was dissociated on an inductively heated single crystal silicon substrate to yield high‐purity silicon. Neutron activation analyses for microcrystalline high‐purity silicon as deposited are given.